Tuesday, 29 June 2010
Monday, 28 June 2010
Photographic technique: Light painting, how to design with the light
The photo that you see is not a Photomontage, is a picture made with the technique of light painting, for we can achieve we need a digital camera that allows to use the manual, a tripod and a torch.
Set the camera on a tripod, make totally dark the Room, adjust the opening time of the camera shutter, the Council for time to step up to 5 seconds, press the Shutter release button and at this point you can give free rein to your fantasy writing your name or using objects to create special effects.
A small tribute to the girl that I love.
A small tribute to the girl that I love.
Sunday, 27 June 2010
Photographic technique: the perspective linear and air
Linear perspective:
This is an extremely interesting and complicated to explain.
When we see the pictures of the Masters or simply of photographers ahead of us, we see now in their photos a sense of depth that usually in photos of a beginner rarely we see. This depends on the way in which it makes use of perspective linear and air.
This is an extremely interesting and complicated to explain.
When we see the pictures of the Masters or simply of photographers ahead of us, we see now in their photos a sense of depth that usually in photos of a beginner rarely we see. This depends on the way in which it makes use of perspective linear and air.
In a subject the prospect linear is created by lines that seem converge towards one or more points of escape.
To give a sense 3d to the photo you to unite these lines. The points of escape may be in the scene or you can also find in imaginary positions out of the camera.
Remember that an image can have one or more points of escape.
To give a sense 3d to the photo you to unite these lines. The points of escape may be in the scene or you can also find in imaginary positions out of the camera.
Remember that an image can have one or more points of escape.
Are to create two or more points of escape when in the image there are lines or areas to a right angle with each other and oblique to the plan of the image.
The lines of the walls of the building seem converge on two points of escape different located outside of the image.to highlight the linear perspective are important point and the angle of recovery, as well as the focal length of objective. If you photographer from short distance with a wide-angle lens will give a perspective accentuated, the horizontal lines which depart converge giving the impression that angles, walls and similar items located nearby devolve in the direction of the camera, while photographing from a distance with a long focal creates a perspective flattened.
The angle of the camera with respect to the main lines of the subject shall determine the areas that will be made more oblique with increase in the feeling of depth and those that will be made from the front, with the opposite effect.
Air prospective:
in a landscape objects located at distances different tend to appear progressively more clear and less controversial man hand that are furthest from the camera, these changes tonal create the prospect air.
In the photos to interiors is useful exploit the prospect air to make it appear an environment much bigger than what is in reality.
in a landscape objects located at distances different tend to appear progressively more clear and less controversial man hand that are furthest from the camera, these changes tonal create the prospect air.
In the photos to interiors is useful exploit the prospect air to make it appear an environment much bigger than what is in reality.
Saturday, 26 June 2010
Photographic technique: photograph with the times long
To begin we need to have a clear idea of what we want from a picture with long exposition, for this I mean from 1’’, even if in some cases you can have wonderful results with even less time, for example, a landscape with flowing water.
It is very important to consider the instruments you use, in this case you may need a trestle proportional to your camera (if you use a reflex with a tele, you need a trestle that is able to hold the weight of the camera and the tele) and have a camera that you can set the exposition manually. As digital cameras work only automatically, you can get good effects keeping the ISO value very low, even if you do not get the same result that you can get with a reflex.
Let's consider starting with a good economic compromise that also allows you to get good results: an average trestle (approx 50 euros) and a bridge digital camera from 250 to 400 euros are between a reflex and a compact camera. They allow you to take pictures to 30’’ or using the Bulb expo, even longer expo.
Let's consider starting with a good economic compromise that also allows you to get good results: an average trestle (approx 50 euros) and a bridge digital camera from 250 to 400 euros are between a reflex and a compact camera. They allow you to take pictures to 30’’ or using the Bulb expo, even longer expo.
I remind you that Bulb expo needs to be used with an outer button or a telecontrol, to avoid the moving effect that you can have pushing the button on the camera. Another method that I always keep the same for my shoots is the ISO value, except a few exceptions, like sport pictures at night, I always set it at a low value, a high value of the ISO can give you a shorter expo, but with a larger noise effect. The noise is represented by that ginned effect caused by a lack of light, where there is not enough light to impress the sensor, the software of the camera stains the pixel with the color of the closest pixel.
Most common applications for long expos are:
Night pictures, where there is enough time to adequately impress the sensor.
In this case if we snap something motionless and with any intrusion of moving subjects, we have to be careful with times to get a balanced picture.
Pictures where there are moving subjects photographed with a ghost effect, but keeping the shape of the subject around them. If we want to snap a square giving the idea of moving subjects, we can use a long expo but keeping the shapes.Pictures where we want to get the light wake of cars. In this case there's maximum space for creativity, but be careful not to make to many composition areas, overexposed or underexposed.
landscapes pictures or twilight sceneries,in this kind of pictures we will get very contrasted colors in skies due to long exposition.
Night pictures to get the stars motion. In this case you must use BULB mode and use a telecontrol. pay attention not to take pictures of the moon, or you will have a unpleasant overexposed wake. Unless this is what you were looking for! You can have astonishing pictures with a static subject and moving stars behind.
Pictures where we want to show the water flowing. In this case you need to set the time according to the light, to the speed of the water e to the result we want. I usually recommend long expo for this kind of shoots, do various tests.Landscapes pictures at sea or lake when we have a little reflux of the water. we can have a moving effect or a kind of blurred. This is a good choice in case of slow flowing of the water.
Long expo with programmed snaps to photograph thunderbolts. In this case you can program when to shoots, and the frequency you need. For example, in a storm you can set you camera in this way: 10" expo, shoot each 20". it may be very easy to shoot a thunderbolt!
If you want to shoot a static subject moving, you can even don't use the trestle.
Pictures with a moved effect, with a more particular subject, playing with the camera without the trestle.
Friday, 25 June 2010
Edith Shain is dead, The nurse of the famous kiss to Times Square
The kiss to Times Square of Alfred Eisenstaedt is probably the photo symbol of the end of the war and hopes for the future that brings with it peace.The photo was taken on 14 August 1945 to Times Square and portrays a sailor kissing passionately an Red Cross nurse . Almost 30 years later Edith Shain wrote the photographer revealing be you the girl of the picture.
Sunday June 20 is dead at age 91 years. It was never known who he was the sailor.
Thursday, 24 June 2010
Photographic technique: the composition of the image - Image Composition in Photography
In this article I'm going to talk about the image composition. I must foresay that many people are able to take good shoots since they have an inner sense of composition,many others learned it little by little. About this topic, I suggest you to read the tutorial on how to train and develop the photographic eye.
The camera, unlike human eye, records everything, so, what at first may elude our sight, will be very clear in the picture,with consequent disappointment of the photographer.
So, before shooting one must attentively examine both the main subject and the minor details,in order not to have unpleasant surprises afterwords (one of the main pros of the digital technique rather then the film one, is that disturbing elements can be easily removed)
I must say that there are no fixed rules that may be (overlooked) broken. In some of the best photos ever design rules are just neglected, but unless you have a inner genius, you had better follow the guidelines.
According to my experience there are 4 main rules that are to be respected
1) Center what you're interested in.this doesn't mean that the subject of the image must be at the center of it, indeed, it's a lot better if the main subject is not centered.
2) Never divide a photo through a vertical or horizontal line crossing its center, e.g. with a pole or a tree. Moreover, the horizon line should be set above or under the center.
For example if you want to take a picture of the sea, the horizon line should never be at the center of the photo, since more importance should be given to the sky or to the water
3) If you want to take a picture of a sunset pay attention to the horizon line not to be oblique, it's awful to see a picture going up or going down. I suggest to shoot many times, until you're sure to have at least a photo with a perfectly straight horizon line.
4) Before shooting, find the best viewpoint, try to frame with the camera in horizontal position, then do the same but rotate the camera of 90°, sometimes this can be enough to change the look of a picture.
You should look for the interesting spot of the scene you want to frame and emphasize it as much as you can, by using the cutting tool during the post-production, or by exploiting the colour range difference between the the subject and the background.
With a light-coloured subject and dark background (or viceversa) you may at once attract observers' attenion.
when you look in the viewfinder, hypotetically trace four equidistant lines: two vertical lines,and two horizontal ones.
Human eye is driven to pose itself on some specific spots,called ''strongest focal points of the image'', that are generated by two lines crossing. These lines will form nine squares.
By now the main subject of your photo should be positioned in one of the crossing points.
Portraying living creatures:
One of the most commonly made mistake is framing a subject by simply putting it at the center of the framing, and not portraying it entirely.
Try to look at a the picture of a persone whose feet were not framed, and whose head was partly cut out; you will perceive a sense of nuisance.
Many people think that all you have to do is portraying a scene that in a precise moment provokes a precise emotion,and then, through that image,make other people feel the same emotion.this couldn't be more wrong.Without study, technique and experience you'll be the only one to feel something when watching a photo, and those feelings are caused by the memories conneted to that image. Photography,as many other forms of art, has its own logic and a click is not enough to convey a message to the watcher.
Article translated by Lucia Piccioni
Tuesday, 22 June 2010
Professional techniques on the digital beauty and fashion retouching - Photoshop Tutorial
In this tutorial I teach you the most professional techniques on the digital beauty and fashion retouching!Sunday, 20 June 2010
Che Guevara effect - Photoshop Tutorial - Photomontage
Taking the picture, pose and frame:
An aspect that we should not underestimate is the framing and the pose you will use, take a look at the famous picture of Che Guevara. We notice:
Both eyes and nostrils are visible, it seems that the photographer stands in front of Che Guevara taking the shot, but it is not like that. Che Guevara is looking right and the photographer stands slightly on the left from the center of his face.
In front of this legendary image of Che Guevara I cite the saying that I like most of him:
“The life of a single man is million times more worth than all the proprieties of the richest man on the Earth” (Ernesto Che Guevara)
In order to take the shot place the camera initially in front of your face, concentrate on a far point to your left (not too much to your left), now move the camera slightly to your right and move the left shoulder forward.
This was my first photo in a “Che version”. The picture at the end of the post instead was my first attempt to create this effect and I used to understand how to imitate properly the picture of Ernesto Che Guevara; I don’t like indeed to pose and I didn’t follow precisely my own instructions. Stages of post-production:
1°) Convert your portrait in black and white.
2°) Use the white brush to delete everything that surrounds your face.
3°) Open your post-production software (Picasa, Corel Paint Shop, Photoshop) and regulate the shadows (to the maximum) and the clarity so that your picture will turn into something similar to a painting.
4°) Download the famous image of Che Guevara from this link.
5°) Open the downloaded image with the post-production software. At this point you have to resize the biggest image among the two so that both will have the same dimension.
6°) With the clone tool just take Che’s cap and hair and bring them on yours and you’re done. I hope your result will be better than mine at the end of the post. If you want to get the “classic” all red image of Che you should jump to the next point.
7°) Export the picture and open it with your post-production software. If you are using Picasa go to Effects - Progressive Tint and select the red color. At the end of the retouches export the picture with max quality and you are done. You can always use Photoshop if you are able to play with levels.
“Me in Che Guevara version, funny right? In post-production I did a mess with proportions though.”
Translation by Nina Kozul
Che Guevara Effect Photoshop Tutorial
How to make the cheguevara Effect
Drawing with the photography, effect Lapis - Corel paint shop pro photo x2
With digital photography can be images that seem design, a nice shot that unfortunately is moved can saved come transforming it into a design.
The photo that you see here above was moved and I decided to try one of the effects of Corel Paint Shop Pro photo x2.
To achieve this effect went on effects -- > design techniques -- > LapisSaturday, 19 June 2010
How to use the layers in Photoshop - Tutorial Photoshop
This is a tutorial for Photoshop. It explains what layers are and how they are useful when working on an image, and provides basic instructions on creating, moving, repositioning and naming layers.Post Production: The cutting, how to cut a photo
A very useful tool, wich the majority of unexperienced photographers underestimates is the cutting tool. A great deal of the photos we take need it in order to be transformed into a perfect image and emphasize the meaning to convey.When we photograph something attractive often we don't make it to frame perfectly the subject we're interested in, subsequently the photo will contain some disturbing elements that may divert our attention.
As you can see either in the photo at the beginning of the article "the wave hug" or in the following one "a revolutionary wall" before post production, the image contained some elements I didn't care about (sea and stones in the first one, pavement and plants in the second one). By cutting away those elements that diverted the attention from what is essential, the meaning I intended to provide the photo with is much clearer.
Article translated by Lucia Piccioni
Thursday, 17 June 2010
How to change the color of the eyes with Photoshop - Photoshop Tutorial
Photoshop tutorial on how to change the color of eyes.
Easily use Photoshop to change the color of someone's eye!
Tuesday, 15 June 2010
5200mm Canon Lens World's MOST powerful Super telephoto EF FD
Canon 5200mm F14 Prime Lens. The world's largest dedicated SLR Super Telephoto lens.Extremely rare. Made in Japan.
Most probably a government ordered cold war spy tool - it certainly wasn't designed to look at the stairs with the use of it's ND filters...
It uses a mirror & lens combination. The front lens is massive.
Rear drop-in filters can be used.
•Focal Length: 5150mm
•Exposure Control: Light quantity is controlled with the use of built-in ND filters, corresponding to f/14, f/16, f/22, f/32
•Minimum Object Distance: 120 meters (Approx 393 feet!)
•Size: 500mm(wide) x 600mm(high) x 1890mm(deep) [20x24x75.6]
•Weight: 100kg (220 lbs) without stand.
From a Canon Flyer:
"This is the only ultra-telephoto lens in the world capable of taking photographs of objects 18 to 32 miles away (30km to 52kms away). Having a focal length of 5200mm, Canon Mirror Lens 5200mm can obtain one hundred times as large an object image as that of a 50mm lens."
"For focusing this mounted or fixed lens on an extremely distant object, two aiming telescopes are set on the side of the lens barrel, and the entire lens is placed on a rigid stand which rotates smoothly. Minimizing the overall length had been a big problem in designing this lens. However, the Catadioptric system that is applied to the other two Canon mirror lenses (Canon 800mm f3.8 & 2000mm f11) has succeeded in reducing it down to one third of the nominal focal length. In general focal length and optical aberration increase with each other, however, our long and persistent research and development have succeeded in solving this problem. Canon mirror lens 5200mm composed of spherical main and secondary mirrors and a correction lens would assure you of clear images."
The magnification of this lens is truly staggering.
If mounted to a Canon XL HD series video camera for example, a reach of 1000x optical (at least) would be possible (approx 37,500mm).
If it was mounted on a DSLR with a crop factor the magnification would be larger still.
The video is a series of stills I took of the lens when I inspected it last year. I have also included video of the simulated magnification (35mm simulation) - all a bit of fun. In fact the maximum video telephoto simulation still just falls short of 3700mm in 35mm terms. So the 5200mm would be much closer & far sharper & distortion free. The video was shot with a Sony PDW 510 16x9 2/3 SD XDCAM disk camcorder with a TV video lens (18x1) using up to 3 optical (x2) extenders. If the 5200mm was hooked up to a video camera we'd be seeing a close up on an eye...
To make it clear - the video is simulated - not shot with the actual 5200mm lens - since it's a "Prime" - how could it be zooming anyhow??!! lol And of course there would be no CA.
Technical digital post production: edges brilliants
The effect of the edges brilliants to find in Corel Paint Shop Pro photo x2 in the effect section -- > Effects artistic -- > edges brilliants there should also be in Photoshop.
I use this effect with photographs that are sharp.
Of course after a readjustment of such will no longer define pictures but graphical work.
Here is other pictures with applied the effect of the edges brilliants:
Printing and Scanning: dots, pixels and DPI
To better understand what we are talking about when we take into consideration printing, scanning and treating of images it is necessary to have clear in mind some concepts about the representation of an image through an electronic device.
In every digital device (the local printer, a scanner, the pc monitor, a post processing software etc…) the image is always formed by a set of single points on a Cartesian coordinate system.
Beyond the spatial coordinates, these points are also characterized by the different color information deriving from the RGB scheme, where for every color cannel it is indicated the value that, mixed with the other channels, will give the final color of that point.
This image gives us a visible explanation of the concept: at the coordinates X=5,03 and Y=20,02 there is a dot with RGB values of R:150 G:141 B:198. In that point we see a clear violet color: indeed the blue value is the highest of the tern, followed by the red value that gives the violet shade tending to magenta.
When we display the single dot that we found (or that dot is acquired by a single photo diode of our camera) we call it pixel. The pixel is simply the base unity of displaying or acquiring of a digital image, together with its coordinates and RGB values.
In digital photography we are referring to the capacity of the sensor using the Megapixels as unit of measure, what does it mean? When we are referring to a particular Megapixel capacity of a digital camera we are stating how many pixel there are on the sensor of that digital camera, regardless of their disposal or geometry.
Be careful, a camera with a square sensor of 2450x2540 pixel is a 6 Mpix camera. Therefore the number of Megapixels will give us only a general description about the sensor.
The indication of the Megapixels of the sensor it is not to be confused with the size in Megabytes of the image: if the Megapixels tell us the number of points that constitute the image, the Megabytes indicates only how much space is needed to record the image on a memory device. This last information though depend very much from the way the image is recorded, the format, the color depth and the potential compression. These are all variables that can change much the size in Megabytes of the image: the same 6 Mpix image could be a 8/10 MB or 1 MB file if saved in uncompressed TIFF format or compressed Jpeg.
Now that we understand the concepts of point and pixel a new variable needs to be introduced: the resolution.
The resolution is a key parameter of the photographic representation and, starting from the concept of point and pixel, it adds the spatial component. The resolution indeed indicates how many points we find in the spatial unity. Now, we should define what the spatial unity is…
Commonly we refer to the resolution in terms of Megapixels assuming as spatial unity the sensor itself. Often indeed we hear that a camera (a compact or a DSLR it does not matter here) has a resolution of 8 Mpix; actually the definition is inaccurate, useful only as a simplification, as different sensors have very diverse physical dimensions. The other way round, when we talk about Dpi, we use a correct and complete unit of resolution since in the unit of measurement we introduce the inch as spatial dimension.
Dpi literally means “Dots per inch”, in other words how many image dots are there in a inch. In the metric-decimal system it indicates how many pixels are there every 2,54 cm since 1 inch = 2,54 cm.
Using a digital camera we should not give too much attention to the resolution taking it into consideration only at the end of the image’s optimization process, when we will print the image or publish it somewhere on the Web. Instead, when we are acquiring an image from a scanner, resolution is the first thing to worry about.
Sunday, 13 June 2010
Free online Photoshop - Adobe Photoshop online edition
Surfing on the web, I discovered a particular and pretty useful page, PHOTOSHOP ON-LINE. Obviously it is not as good as the retail Photoshop version, but you can find different features for the pictures post-production (contrast regulation, brightness, curves, cutting, imaging rotation, filters…).
Oddly it's also pretty fast for a webpage), and anyway i prefer to use it instead of other softwares (for example Picasa..). However it will not replace the retail version of Photoshop which is still an essential tool for everyone who really take photography seriously.
This is the link to use immediately Photoshop online: https://www.photoshop.com/
Translation by Alessandro Amante
Friday, 11 June 2010
Unsharp Mask - Tutorial Photoshop
Between all the filters for Photoshop the more essential is the Unsharp mask.1°) In the photos normal, used with a setting soft, helps to increase the feeling of sharpness of image.
2°) In photo slightly sharp, used with Settings more accentuated allows to recreate the feeling of focus exact.
Opening Photoshop, is situated in Filters > Contrasts > Unsharp Mask. All activation of the filter is it opens a dialog with three adjustable parameters: factor, radius and threshold. Let's see how it works in detail.
Physical principles
The eye perceives an image countered, more clear of a more soft. There is a significant difference between retail and contrast of a image. The detail is an intrinsic quality determined by the quality of the sensor and the goodness of objective. The contrast is a quality more linked to the capacity of observer to perceive better or worse the edges or the limits of an element.
The Unsharp Mask that is able to increase the contrast between the objects, creating a greater feeling of sharpness, but the level of detail will always remain the same. A greater contrast he manages to distinguish more clearly the details of a file, but we cannot increase it indiscriminately why would the alteration of tones and colors of the pictures.
The filter mask of contrast, applied to a file, affects only the demarcations between the difference in brightness in the details and in subjects.
Alter excessively the contrast to obtain images more sharp can be profitable side effects unpleasant. alter the contrast only in the edges of objects is useful to sharpness, without side effects evident on the tones.
In practice
It is difficult to of certain answers in areas where prevail the subjectivity and creativity. We feel in any case to advise all the use of the filter mask of contrast to their own photos. give what we could define a notional sharpness pictures, it in the right measure, which can be found in an appropriate by applying the three settings (factor, the radius and the threshold) that appear in the window of dialogue of Photoshop, going on filters > contrasts > Unsharp Mask.
The factor determining how much difference of contrast we apply within the edges of the objects of our image. greater the value of the factor, the greater the contrast peripheral applied. It is a good rule do experiments because the final result also depends on the initial image. A factor 100 is good for machines with 4-5-megapixel but may be insufficient for sensors with 4 Mpixels. to higher values could become visible effect grain that highlights the noise of digital image.
The radius, determined in pixels, is the parameter that influence the thickness of the line of demarcation between the subject. A line too thin prosecutor changes not visible to eye, exaggerations can create ruts on the whole picture. Also this parameter is affected by the capacity of our sensor. More pixels has our image, the greater the radius to apply to the mask of contrast to have an equal effect.
It is difficult to of certain answers in areas where prevail the subjectivity and creativity. We feel in any case to advise all the use of the filter mask of contrast to their own photos. give what we could define a notional sharpness pictures, it in the right measure, which can be found in an appropriate by applying the three settings (factor, the radius and the threshold) that appear in the window of dialogue of Photoshop, going on filters > contrasts > Unsharp Mask.
The factor determining how much difference of contrast we apply within the edges of the objects of our image. greater the value of the factor, the greater the contrast peripheral applied. It is a good rule do experiments because the final result also depends on the initial image. A factor 100 is good for machines with 4-5-megapixel but may be insufficient for sensors with 4 Mpixels. to higher values could become visible effect grain that highlights the noise of digital image.
The radius, determined in pixels, is the parameter that influence the thickness of the line of demarcation between the subject. A line too thin prosecutor changes not visible to eye, exaggerations can create ruts on the whole picture. Also this parameter is affected by the capacity of our sensor. More pixels has our image, the greater the radius to apply to the mask of contrast to have an equal effect.
The threshold is a parameter of tolerance that ours to mask to indicate when must operate and when not. A threshold set on 2 indicates that the mask will be applied on all the edges of tones that will have a difference of contrast equal to or greater than 2 levels. By applying, therefore, numbers high on the threshold will be less L effect of the mask. With numbers very low, the mask of contrast will be applied to the whole L image. This factor is not influenced by the services of the sensor.
In conclusion, it do experience with this filter: Make experiments and ponder the results mainly to print completed (effect to monitor is less clear). Save your originals modified with alternative names or as copies. You can find the parameters perfect for your digital camera, when you feel more secure then, but only then, you can apply the effect to all your images, will the effect sharpness without exceeding in fact too visible.
Wednesday, 9 June 2010
Nikon D300s or D300? Differences and characteristics
Reading the tests would appear to have improved, but the changes to the d300 are not many.It is largely the same machine but with some revisiting, the striking thing is that the d300 arrived in 2007 and also in the version "S" do not see themselves major changes, is also that they are preparing to launch of a d400 to keep in step with the 7d Canon.
In fact if not interested in the video and do n't want to spend the figure may yet convenient as the ratio quality/price the d300 that lies much less, buy second-hand in good conditions you can do the deal.
Technically better there is a certain held on the high ISO, even if the owners of d300 is already very good.
Opinion of an owner of d300s:
I have the 300s but I never owned the 300.In substance it is better buy one d300 used in good condition and with the money they have saved buy a good objective.
It is true was improved about senior ISO, but proven near a d300 I saw this abysmal difference.
1600 the noise begins to escape and I think that even on 300 is the same.
Can be comfortable double slot, but for an amateur use is not a fundamental thing.
The Movies is true it makes them, but the focus is really uncomfortable.
Tuesday, 8 June 2010
Photographic technique: Depth of field and aperture
First part
I thought about writing some tutorials with the basics, to help those who approach for the first time in the world of SLR. The tutorial is divided into 2 parts, the first is essential, the second called “Further Reading” contains more complex concepts that you should ignore until you become very familiar with the first part of the tutorial, and even then you might not ever need to read it. If your passion will grow, i strongly recommend to buy some good books to improve your knowledge.
The aperture is a device by which we can adjust the amount of light that reaches the sensor. It consists of a series of blades that slide over one another by closing and opening a central hole through which light passes, as does the iris with the eye. To better understand we are making an hydraulic example, to make your picture look good the sensor/film have to receive the correct amount of light. We imagine that the sensor is a bathtub; to take a bath you need to get a certain amount of water (water = light) the tap (= aperture) dosing the water flow and the time it takes to fill up the tank is the exposure time.
Typical values of aperture are:
f/1 - f/1.4 - f/2 - f/2.8 - f/4 - f/5.6 - f/8 - f/11 - f/16 - f/22 - f/32
Of course there are also intermediate values (see Further Reading)
At this point you need another effort to understand what is the depth of field, or more briefly the DoF. Our eye does not have an infinite resolution, at a certain point it is no longer able to distinguish when two points are simply very close or when they are actually a single point, on this fact is based the concept of circle of confusion (see Further Reading) that means that we see as a single point what is actually composed of two or more points. If we focus on a subject at a distance of 4 meters, everything at 4 meters will be perfectly in focus; what is beyond (even at 4.01 m) or closer will be out of focus, in reality thanks the inability of the human eye to distinguish points that are too close, the focus is not so selective, so we met with the depth of field that is a measure of how this area of clearness is extended!
Summing up the DoF is the space that appears sharp in front and back to our subject.
It depends only on the focal length and the aperture (see details).
Why that happens?
The more the aperture is open the wider is the beam of light that draws on our image sensor, and thereby the larger the dots (circles of confusion, see Further reading) the smaller the sharp clear; the smaller the beam of light, the more accurate is the brush that paints the picture and then more extensive is the area of clearness in front of and behind the subject, actually other factors are involved , but on the whole you can consider it true (see details).
Let's take a look at these pictures to understand how the DoF varies in function of the aperture set.
The focus is on the third jar
Lens 50mm @ f4
Lens 50mm @ f16This approximate diagram shows the depth of field of a 50mm open aperture with a range of subject matter at a distance of 5 meters (red line), the blue area indicates the PDC, you can read the value in meters on the right-hand scale.
In that we always use the 50mm, but our subject is placed at 10 meters (red line), we see how it changes the PDC:
Notice how the PDC in some cases extends well beyond 12m of my scheme, a case comes to infinity, that is all that is behind the subject appears in focus.
The charts catches your eye as the PDC before the subject is less extensive and more behind the subject! From this we draw an important lesson: The depth of field extends for 1/3 before the subject and 2/3 behind.
Now that we know what aperture is we can exploit it, remembering this simple rule, to remove the subject from the background, it is better to use a wide aperture, as in this photo.
The charts catches your eye as the PDC before the subject is less extensive and more behind the subject! From this we draw an important lesson: The depth of field extends for 1/3 before the subject and 2/3 behind.
Now that we know what aperture is we can exploit it, remembering this simple rule, to remove the subject from the background, it is better to use a wide aperture, as in this photo.
Aperture f4While to have a clear area as wide as possible is better to use a closer aperture like in this one:
Aperture f16We have to remember that the zone of clearness is extended 1/3 before the subject and 2/3 behind it. Look at how we can use the DoF to increase the clear area. We take in exam the picture of the cans in a row, compared to the first picture we have the same aperture but taking into account the DoF we have focused on the element located approximately 1/3 (hence the second jar) and not on the third jar which actually is the subject of the photo, so we have further expanded the clear area.
Lens 50mm, f16, focus on the third jar.
Lens 50mm, f16, focus on the second jar.
Lens 50mm, f16, focus on the second jar.Notice how in the last picture all the jars are easier to read, even the one in the foreground is sharper, and that just varying the point focused.
If we don't care to obtain a blurred background instead of a perfectly clear one we can set an intermediate opening of the aperture, that will grant a higher sharpness (see Further Reading).
So far we have seen how the DoF is affected by the aperture, now we have to see what changes by using different focal lengths! The larger is the lens focal length (for now we say its mm) the smaller is the depth of field that we'll have, vice versa for the same aperture with a shorter focal length we'll have a greater DoF.
This approximate scheme should remove any further questions:
If we don't care to obtain a blurred background instead of a perfectly clear one we can set an intermediate opening of the aperture, that will grant a higher sharpness (see Further Reading).
So far we have seen how the DoF is affected by the aperture, now we have to see what changes by using different focal lengths! The larger is the lens focal length (for now we say its mm) the smaller is the depth of field that we'll have, vice versa for the same aperture with a shorter focal length we'll have a greater DoF.
This approximate scheme should remove any further questions:
The blue area indicates the depth of field that you have with that lens set at f5,6 with the subject at 5 meters (red line).
Observe how the change of focus not only allows expand or shrink the frame, but also that with the same aperture with a wide-angle lens the clear zone is much wider than with a telephoto lens.
We note that the DoF is a feature of the lens/aperture size and then also changing the sensor/film it remains the same! A 50mm at f/8 will have the same DoF on an SLR with APS-C, on a 35mm film, a 6x6cm or on an optical bench to 10x15cm.
I'll finish by saying that there is only a single plane that is actually in focus (red line drawings), and that the DoF makes acceptably in focus even the close subjects, but a picture enlargement would make this clear, making plain the difference of sharpness between the subject on which you have focused and what it have around!
This should be viewed only after having understood and experienced the first part. If after reading this part you feel a strong headache or are overtaken by a panic attack, it is not my fault, I warned you! ;)
We have to make a short introduction: what mainly distinguishes a focal from another is the angle of field, or how big is the slice of world that i can put in my photos, witha a wide-angle lens i can embrace a wide open spaces, while a telephoto lens can capture only particulars, as a matter of principle, I could take a picture of a group of friends wih a wide-angle lens and then cut the head of one of them and make a close-up, and I would get the first plane that I could do using a telephoto lens to isolate it from the group.
When you say that in digital photography DoF is greater, in fact you are saying an half-truth (or marketing lie). In digital photography using a sensor smaller than full size, you use only the most central part of the picture provided by the lens; then you get what is called ‘equivalent focal length’, in truth you are actually making only a cut-out of the central part of the picture, with the result that seems to be made with a focal similar to a telephoto but when printing you have to enlarge more the picture to cover the same sheet of paper. So a 50mm APS-C format, il give a frame equal to an 80mm full size, but the DoF, bound only to focal and aperture, remains the same! That's why there is a feeling of greater DoF with the same pictures!
I can get the same picture with the same framing with an higher DoF: the one of 50mm, rather than the one of 80mm!
A real fun for macro photography lovers and a true disgrace for those who love portraits. To throw water on the fire I would point out that moving to a larger format such as the full frame or 35mm or Leica format if you prefer to call it that way, there is the opposite phenomenon: the 50mm which in the digital reduced format was a small telephoto lens, and in cameras full size was a normal lens, in medium format (120 or 6x6) it behaves as a wide angle. So the digital has discovered new optical phenomena, therefore the digital never discovered new optical phenomenons but has only provided input to the marketing staff to create false hopes to sell more.
This should be viewed only after having understood and experienced the first part.
Before the autofocus invntion, and also now suring situations where is not possible to focus with precision, we can use this tecnique to ensure an entirely focused imagefrom a certain distance and beyond. Everytime we choos a focal and an aperture there is a particular distance to focus, called hyperfocal thanks to wich everything placed btween half od the hyperfocal untill infinite is on focus. Times ao on the lenses there was written the scales of DoF and there was a notch that helped you to set the hyperfocal in few seconds, nowadays (unfortunately) it's not used to mark it, but fortunately is always more common to find the button that makes you see the DoF directly during the shooting, avoiding us every calculation related to the DoF prediction, but if you want to know the hyperfocal length of you camera you have to take a pen, a calculator an much patience!
Let's see the an approximate formula to calculate your hyerfocal DoF:
F = Lens Focal Lenght in mm
f = Aperture value
c = Circle of confusion diameter, normally considere equal to 0.025mm
d = Subject distance
I = Hyperfocal
I = (F x F) / (f x c)
Nearest focus point = (I x d) / (I + d)
Farthest focus point = (I x d) / (I - d)
Depth of Field = Farthest focus point – Nearest focus point
For example:
Focal = 50mm
Aperture = f/8
c = 0,025mm
I = (F x F) / (f x c) = (50 x 50) / (8 x 0,025) = 12500mm = 12,5meters
Hence with a 50mm on f16 with a focus at a distance of 12,5m everything will be on focus between da 6,25m till infinite.
Nearest focus point = (I x d) / (I + d) = (12,5 x 12,5)/ (12,5+12,5) = 6,25metri
Farthest focus point = (I x d) / (I - d) = (12,5x12,5)/(12,5-12,5) = 156,25/0 = infinite
Pay attention when the measures are in mm or in meters!
Unlik what a friend of mine thought, it’s not the club of mothers in law, but the limit of distinction of two points. As I mentioned earlier, when two points are placed too close they are confused, and you see one. This limit is not fixed and varies with focal length and aperture used, it is generally taken to be equal to 0.025 mm, but this is only a theoretical value determined on the maximum resolving power of the eye under the best conditions: distinguish 5 black lines on a white background 30cm away. Changing the background or lines color lower the ability of the eye to distinguish details, also increasing the viewing distance dramatically lower the ability to distinguish details, so the circle of confusion is increased in size. Now it should be clearer because those 0,025 mm are just a maximum theoretical value.
Because light intensity decreases with the square of the distance. For example, if 1 meter it is worth 100lux, 2 meters are worth 25lux to make uniform the change of the parameters with the change of the lens, it was decided to set the Aperture for the lens. Then f/8 makes the same amount of light hit the sensor whether it refers to a 300mm or a 17mm; the f indicates precisely the focal, if we calculate focal/8 we get the effective aperture in millimeters, for example, with a 300mm we'll have 300/8 = 37.5 mm while with a 17mm we'll have 17/8 = 2.1 mm, although it is always viewed as an aperture f/8, the opening is actually different! Passing from a value to the next the amount of light that reaches the sensor doubles, in fact it doubles the area, due to the nature of light that fades so fast! This explains why the aperture values are so unusual and because they are multiples of the square root of 2.
Note that the maximum aperture is the diameter of the front of the lens, except for some special optical patterns! That’s why the brightest optics are larger and therefore more expensive ... optical glass is very expensive!
Why is the view with wider aperture worse? The construction of lenses, in particular glass production, fails to produce a glass perfect in every detail, that's why the central part of the lens have an higher quality than the peripheral parts, also the rays of light coming in the more remote areas are subject to a greater deviation resulting in greater attenuation so there is often a decrease of light at the edges of the image.
Why is the view with smaller aperture worse? The light in the lens is usually treated as a wave that meets precise geometric laws; unfortunately, when the hole (aperture) from which it pass it starts to be too small, you encounter a particular phenomenon of interference: the diffraction, which makes the light"scatter" highlighting its wave nature.
Because of diffraction our beam of light varies greatly in size, for example consiering a lens with a focal length of 50mm an aperture with f2 and f22 we have that due to diffraction at f2 to our beam of light is about 2.7 micrometers and at f22 is about 30micrometers, this is a big difference, and if it were not for construction restrictions the best quality would always be given by the wider aperture. For these numbers i will not show the calculations because it is unimportant for the goal of this example; for a more detailed explanation, I recommend reading some good books on optics or a physics textbook. We observe how, unlike the common belief, that the beam of light draws our image actually in a more accurate way with a wider aperture.
Why are the intermediate apertures better? Because they take advantage of the central part of the lens which is produced more accurately and with the light that comes with the best angle and the apertures that are still sufficiently large in order to avoid diffraction.
Why when I look at the viewfinder i do not see exactly the same DoF, but everything seems more blurred? To enable easy viewing, cameras keep the aperture fully open so that the viewfinder is as bright as possible and close the lens aperture for the photo at the established value, only a fraction of a second before the shot. So normally we see in the viewfinder the PDC that we would have with the widest aperture (= the smallest number); some cameras have a button that allows you to close the lens aperture set to assess the actual DoF in the viewfinder before the shot! By doing this the viewfinder becomes darker, but generally it is bright enough to allow you to understand what is really in focus and what is not.
As soon as you start playing with the DoF and apertures you'll realize that having everything in focus, it's easy! Just use closed apertures and play with the DoF remembering that it extends for 1/3 before the subject and 2/3 behind it. The problem is that using closed apertures requires a lot of light, high ISO values and slow times, so in the most of situations this is not possible or at least complicates things forcing us to use a tripod and a slow shutter speed or sacrificing quality by using high levels of sensitivity.
Since the aperture is made with the overlap of a series of blades, the hole isn't circular but has a shape depending on the number of blades, for example with 6 blades we'll have an hexagonal hole, only at the widest opening we obtain a circular hole.
Observe how the change of focus not only allows expand or shrink the frame, but also that with the same aperture with a wide-angle lens the clear zone is much wider than with a telephoto lens.
We note that the DoF is a feature of the lens/aperture size and then also changing the sensor/film it remains the same! A 50mm at f/8 will have the same DoF on an SLR with APS-C, on a 35mm film, a 6x6cm or on an optical bench to 10x15cm.
I'll finish by saying that there is only a single plane that is actually in focus (red line drawings), and that the DoF makes acceptably in focus even the close subjects, but a picture enlargement would make this clear, making plain the difference of sharpness between the subject on which you have focused and what it have around!
PART TWO
This should be viewed only after having understood and experienced the first part. If after reading this part you feel a strong headache or are overtaken by a panic attack, it is not my fault, I warned you! ;)
DoF and the digital equivalent focal
We have to make a short introduction: what mainly distinguishes a focal from another is the angle of field, or how big is the slice of world that i can put in my photos, witha a wide-angle lens i can embrace a wide open spaces, while a telephoto lens can capture only particulars, as a matter of principle, I could take a picture of a group of friends wih a wide-angle lens and then cut the head of one of them and make a close-up, and I would get the first plane that I could do using a telephoto lens to isolate it from the group.
When you say that in digital photography DoF is greater, in fact you are saying an half-truth (or marketing lie). In digital photography using a sensor smaller than full size, you use only the most central part of the picture provided by the lens; then you get what is called ‘equivalent focal length’, in truth you are actually making only a cut-out of the central part of the picture, with the result that seems to be made with a focal similar to a telephoto but when printing you have to enlarge more the picture to cover the same sheet of paper. So a 50mm APS-C format, il give a frame equal to an 80mm full size, but the DoF, bound only to focal and aperture, remains the same! That's why there is a feeling of greater DoF with the same pictures!
I can get the same picture with the same framing with an higher DoF: the one of 50mm, rather than the one of 80mm!
A real fun for macro photography lovers and a true disgrace for those who love portraits. To throw water on the fire I would point out that moving to a larger format such as the full frame or 35mm or Leica format if you prefer to call it that way, there is the opposite phenomenon: the 50mm which in the digital reduced format was a small telephoto lens, and in cameras full size was a normal lens, in medium format (120 or 6x6) it behaves as a wide angle. So the digital has discovered new optical phenomena, therefore the digital never discovered new optical phenomenons but has only provided input to the marketing staff to create false hopes to sell more.
Calculating DoF and Hyperfocal lenght
This should be viewed only after having understood and experienced the first part.
Before the autofocus invntion, and also now suring situations where is not possible to focus with precision, we can use this tecnique to ensure an entirely focused imagefrom a certain distance and beyond. Everytime we choos a focal and an aperture there is a particular distance to focus, called hyperfocal thanks to wich everything placed btween half od the hyperfocal untill infinite is on focus. Times ao on the lenses there was written the scales of DoF and there was a notch that helped you to set the hyperfocal in few seconds, nowadays (unfortunately) it's not used to mark it, but fortunately is always more common to find the button that makes you see the DoF directly during the shooting, avoiding us every calculation related to the DoF prediction, but if you want to know the hyperfocal length of you camera you have to take a pen, a calculator an much patience!
Let's see the an approximate formula to calculate your hyerfocal DoF:
F = Lens Focal Lenght in mm
f = Aperture value
c = Circle of confusion diameter, normally considere equal to 0.025mm
d = Subject distance
I = Hyperfocal
I = (F x F) / (f x c)
Nearest focus point = (I x d) / (I + d)
Farthest focus point = (I x d) / (I - d)
Depth of Field = Farthest focus point – Nearest focus point
For example:
Focal = 50mm
Aperture = f/8
c = 0,025mm
I = (F x F) / (f x c) = (50 x 50) / (8 x 0,025) = 12500mm = 12,5meters
Hence with a 50mm on f16 with a focus at a distance of 12,5m everything will be on focus between da 6,25m till infinite.
Nearest focus point = (I x d) / (I + d) = (12,5 x 12,5)/ (12,5+12,5) = 6,25metri
Farthest focus point = (I x d) / (I - d) = (12,5x12,5)/(12,5-12,5) = 156,25/0 = infinite
Pay attention when the measures are in mm or in meters!
Circle of confusion
Unlik what a friend of mine thought, it’s not the club of mothers in law, but the limit of distinction of two points. As I mentioned earlier, when two points are placed too close they are confused, and you see one. This limit is not fixed and varies with focal length and aperture used, it is generally taken to be equal to 0.025 mm, but this is only a theoretical value determined on the maximum resolving power of the eye under the best conditions: distinguish 5 black lines on a white background 30cm away. Changing the background or lines color lower the ability of the eye to distinguish details, also increasing the viewing distance dramatically lower the ability to distinguish details, so the circle of confusion is increased in size. Now it should be clearer because those 0,025 mm are just a maximum theoretical value.
Why are the Aperture values numbered so strange?
Because light intensity decreases with the square of the distance. For example, if 1 meter it is worth 100lux, 2 meters are worth 25lux to make uniform the change of the parameters with the change of the lens, it was decided to set the Aperture for the lens. Then f/8 makes the same amount of light hit the sensor whether it refers to a 300mm or a 17mm; the f indicates precisely the focal, if we calculate focal/8 we get the effective aperture in millimeters, for example, with a 300mm we'll have 300/8 = 37.5 mm while with a 17mm we'll have 17/8 = 2.1 mm, although it is always viewed as an aperture f/8, the opening is actually different! Passing from a value to the next the amount of light that reaches the sensor doubles, in fact it doubles the area, due to the nature of light that fades so fast! This explains why the aperture values are so unusual and because they are multiples of the square root of 2.
Note that the maximum aperture is the diameter of the front of the lens, except for some special optical patterns! That’s why the brightest optics are larger and therefore more expensive ... optical glass is very expensive!
Does the best aperture exist?
Why is the view with wider aperture worse? The construction of lenses, in particular glass production, fails to produce a glass perfect in every detail, that's why the central part of the lens have an higher quality than the peripheral parts, also the rays of light coming in the more remote areas are subject to a greater deviation resulting in greater attenuation so there is often a decrease of light at the edges of the image.
Why is the view with smaller aperture worse? The light in the lens is usually treated as a wave that meets precise geometric laws; unfortunately, when the hole (aperture) from which it pass it starts to be too small, you encounter a particular phenomenon of interference: the diffraction, which makes the light"scatter" highlighting its wave nature.
Because of diffraction our beam of light varies greatly in size, for example consiering a lens with a focal length of 50mm an aperture with f2 and f22 we have that due to diffraction at f2 to our beam of light is about 2.7 micrometers and at f22 is about 30micrometers, this is a big difference, and if it were not for construction restrictions the best quality would always be given by the wider aperture. For these numbers i will not show the calculations because it is unimportant for the goal of this example; for a more detailed explanation, I recommend reading some good books on optics or a physics textbook. We observe how, unlike the common belief, that the beam of light draws our image actually in a more accurate way with a wider aperture.
Why are the intermediate apertures better? Because they take advantage of the central part of the lens which is produced more accurately and with the light that comes with the best angle and the apertures that are still sufficiently large in order to avoid diffraction.
Can I know the DoF before the shot?
Why when I look at the viewfinder i do not see exactly the same DoF, but everything seems more blurred? To enable easy viewing, cameras keep the aperture fully open so that the viewfinder is as bright as possible and close the lens aperture for the photo at the established value, only a fraction of a second before the shot. So normally we see in the viewfinder the PDC that we would have with the widest aperture (= the smallest number); some cameras have a button that allows you to close the lens aperture set to assess the actual DoF in the viewfinder before the shot! By doing this the viewfinder becomes darker, but generally it is bright enough to allow you to understand what is really in focus and what is not.
Can I have everything in focus?
As soon as you start playing with the DoF and apertures you'll realize that having everything in focus, it's easy! Just use closed apertures and play with the DoF remembering that it extends for 1/3 before the subject and 2/3 behind it. The problem is that using closed apertures requires a lot of light, high ISO values and slow times, so in the most of situations this is not possible or at least complicates things forcing us to use a tripod and a slow shutter speed or sacrificing quality by using high levels of sensitivity.
Curiosity:
Since the aperture is made with the overlap of a series of blades, the hole isn't circular but has a shape depending on the number of blades, for example with 6 blades we'll have an hexagonal hole, only at the widest opening we obtain a circular hole.
Article written by Attilio and translated by Alessandro Amante
Adjusting the contrast and brightness in a photo
One of the fundamental post-production tools is the setting of contrast and brightness tool.
To set contrast and brightness is a necessary step, especially for those who use the Bridgee or Reflex kind of camera, they shoot with a contrast and a brightness wich is lower than the average one (unlike compact cameras,made for 'ignorant' users) to give the photographer himself the opportunity to set this values.
By increasing the contrast of a photo you'll get more vivid colours. Choose a photo you've just taken, increase the contrast and adjust brightness,save the image with a nother name and close everything. re-open both the original one and the one you've just modified then compare them.
You'll notice that there's difference in between.
To set a concrete example I'll upload a photo before and after the post-production process. It's up to you to tell the difference.
The picture to top of this article was increased the contrast and adjusted the brightness, the pictures to end of the article is the original without changes. The final result is clear.
Article translated by Lucia Piccioni
Friday, 4 June 2010
Photographic Technique: Night Photography, How to take a photo at night
How many times have we seen wonderful nocturnal images of cities, with those unreal lights whose transform common urban landscapes into misterious places, with fantastic lights and colours?
Now we have a fork in front of us: taking pictures in the "blue time" or true nocturnal photos. During the blue time (which lasts about twenty minutes), the sun is still rising, or setting, therefore we can still use a short enough shutter time and get pictures with both a beautiful blue sky and the city illumination on. Whiles in a nocturnal picture we will get a black sky (or at most with moonlight) and the city lights.
Luckly for us, April and May are the best periods over the year for such kind of of photos, because dawns and sunsets last longer and the weather is quite good. Often, better results can be achieved just after the sunset or before the dawn.
Let's start talking about nocturnal photography, what do we need? Our thrusted reflex camera and our lenses, a tripod (better if has a level), an electric torch, a notepad, a pen, spare batteries, film rolls or memory cards, a remote shoot control and a cronometer (a wrist watch is pretty good).
Very easily, our exposure time will be of the order of between ten second and some minutes! Therefore we will need to use "Bulb" (or B) time quite often, with the camera mounted over a tripod and the remote shoot control to avoid unwanted vibrations and movements during the long exposure time. Moreover, during such long exposures, it is a good practice to cover the viewfinder in order to avoid light infiltrations that could affect the exposimeter or even the image sensor. This is a quite uncommon likelihood, but why should we risk that?
If our camera does not have the B-time option (really a serious lack), we are forced to take pictures during the blue time or in few lucky nocturnal situations.
Now we have in front another fork. If we have a film camera, we have to remember that for exposure times longer than 10 seconds, the reciprocity law no longer holds, due to the Schwarzschild's effect (or lack of reciprocity). In other words, if the exposimeters indicates 10''@F/8, due to the lack of reciprocity the exposure will not be the same (or equivalent) at 20''@F/11. Then what can we do?
As a first reference, we can adopt the following values remembering that they can vary depending of the film used.
- from 10'' to 20'' + 1 stop
- from 20'' to 100'' + 2 stop
- more than 100'' + 3 stop
Of course, the transition between the above correction factors is not so marked. Remember that you can also use stop fractions.
Therefore, if our light meter indicates 10'' F/8, the correct exposure time should be 40'' F/11.
As a further complication, for exposure times longer than 10 seconds, color films are usually affected by color alterations, so it is highly recommendend to use always the same film type in order to predict its behaviour in such situations. Moreover, this could be a typical case where bracketing may not be a waste of film. The use of a negative color film is recommended for nocturnal photography, thanks to their wider exposure latitude (better tolerance of exposure errors).
If, instead, we have a digital reflex camera, the lack of reciprocity will not be a problem for us and we can follow the light meter indications. Moreover, we can see a preview of the image in the camera display and this is a great advantage over film cameras. However, digital cameras also have their drawbacks in nocturnal photography. In particular, digital image sensors performs worser during long exposure times, due to the additive effect of noise. In other words, the longer is the exposure time, the higher will be the noise level in the picture. In order to reduce this problem, some camera manufacturers have implemented the dark frame method: in practice, the camera takes two shoots, one of the real scene and the other is a dark frame, taken in the same condition of the first shoot, that contains only the noise. At this point, the camera software subtracts the dark frame from the first shoot, resulting in a quite effective noise canceling method (the hipothesis is that noise is almost the same both in the scene shoot and in the dark frame). If your camera does not have this function, you can still improve your image in terms of noise during post-processing, by using a specific software like one of the following:
http://www.neatimage.com it isn't free, it also is a Photoshop filter
http://www.picturecode.com download Noise Ninja
http://www.imagenomic.com download Noiseware
Do not expect miracles from these software, but they can actually improve your shoots.
It is not unusual to find some faulty pixels in an image taken with an exposure time of ten seconds or longer. They can be easily recognized as white/grey spots in areas where they should not be, or even red, green or blue dots.
There exist a free software that recognize dead pixel by analyzing your picture files, it is Dead Hot Pixel Test, and can be downloaded at: http://www.starzen.com/imaging/deadpixeltest.htm.
Hot pixels are damaged pixel, locked to a single color that are going to burn, while dead pixels are alreay burnt ones.
If you will find your camera has some dead or hot pixel, and it is still under warranty period, you should check your warranty conditions and try to get your camera repaired. Otherwise, don't worry about that, because dead and hot pixel can usually be noticed for exposure times longer than 1/15'' and they can be easily removed during post-processing.
As a further consideration, in the topic of nocturnal photography, we have to discuss about color balancing. If we will make use of daylight films, or daylight settings on our digital camera, as a result we will highlight the color of each light source in the scene, and we should be conscious that it would be almost impossible to compensate for all color casts (in the event we want to do so). As a reference for chromatic dominants, we can consider the following:
- Tungsten, halogen and street lamps give a red/orange colored light;
- Fluorescent lamps give a blue/green color cast;
- Sodium lamps give a reddish color.
Human eye hardly recognize such chromatic dominants (except for few extreme cases), therefore owners of digital cameras are advataged from this point of view.
Now that we knew our equipment and its limitations, can join the fray, let's choose a subject: a well illuminated building, a glimpse of our city as seen from above, a square, a statue, a street... whatever stimulates our fantasy, and let's start to work. on the contrary of what one might think, the best results are achieved with a sensitivity of 100 ISO and a pretty close apertures, F/8 or F/11, where F/11 should be preferred for telephoto lenses. It is, obviously, possible to use different aperture values, in order to achieve different effects. However, nocturnal photos should have good depth of field and sharpness.
You can find lots and lots of quite useless reference tables reporting time and apertures values suggested for several shooting situations, but they will be a waste of time and film for you, because nocturnal photography is a test-bench for your ductility as photographers!
Just keep in mind that if you include the moon in your scene, then you should use exposure times shorter than 1/4'',otherwise you will get the moon's shining path on your picture.
We have to choose the right focal lenght for our subject and, once we have found a good viewpoint, measure the light of the scene. It is recommended to measure exposure only, or almost only, on the brighest area of the scene and take note of the values, for example 1/8''@F/8, then measure a dark area of the subject that we want to be visible in the picture, suppose we get 8''@F/8. Now we can, at least initially, take the average value for the exposure time, and then 1" (1/8 - 1/4 - 1/2 - 1 - 2 - 4 - 8), hence set the camera to 1"@F/8. It is highly recommended to set bracketing with at least one shoot more with longer exposure time.
In order to enhance the accuracy of light measurement in those bright or dark points of the scene, to better isolate them from the rest of the scene during measurement operation, just point at them with a wide angle lens, a zoom set at 200mm, or simply get closer to that points.
If the light meter of your camera is not able to perform a light measurement, you can try to trick it by setting a higher ISO value, either in film or digital cameras; take the exposure measurement and then compensate it for the correct ISO value. For example, if the light meter cannot provide time values longer than 30''@F/8 100 ISO, first try to measure at higher apertures, say F/5.6 or F/4, if the light meter gives a valid reading, for example 30''@F/4, in order to compensate this reading for the correct aperture, we should set (30''@F/4 - 60''@F/5.6 - 120''@F/8) 120"@F/8. Then, if we are using a film camera, also have to compensate the latter value for the lack of reciprocity with an increment of +3 stops, and then it will be 960''@F/8!!!
Alternatively, you can set the sensitivity to the highest ISO value available, say 1600 ISO, in such a way the camera light meter should provide a reliable reading, let's suppose 15''@F/8, and then we will have (15''@1600 ISO, 30''@800 ISO, 60''@400 ISO, 120''@200 ISO, 240"@100 ISO) 240''@100 ISO F/8 (again, enhance this reading by 3 stops if you have a film camera, in order to compensate the lack of reciprocity).
You can easily recognize how quickly exposure times rise. It is quite common to deal with seconds and minutes, therefore a chronometer is needed in order to measure such long times, and a small electric torch could be very useful to allow reading the chronometer and to find things in our bag. With such long exposure times, a difference of the order of few seconds usually does not results in visible errors, therefore if you use bracketing set it to -1/+1/+2 stop relative to the exposimeter reading and with high probability you will get good nocturnal photos.
As a last recommendation, remember that in some cities it is forbidden to place the tripod on the ground, but not on the trash cans or the benches. Moreover, some buildings may be protected by copyright, therefore you cannot take pictures of them and show it to others, so try to find out about the situation before shooting. It could be useful to visit the place you want to photograph during the day. In my opinion, the better hours to take nocturnal photographies are those after midnight in working days, when cities are desert.
If you want to include people in your nocturnal pictures, take into account that with exposure times longer than 1/15'', they will appear as wakes or ghosts, unless they are still.
Also, beware of cars. If their lights point directly to the camera lens, your picture is definitively compromised, while if they move transversely with respect to the lens, their lights will produce shining paths on the picture.
A notepad and a pen can be useful in order to calculate the exposure value after several measurements in different points of the scene and, especially if you use a film camera, it could be the case of taking note fo each exposure value, in order to avoid the same errors next time!
It is a good practice ckecking the longest exposure time in the Bulb (B) mode on your camera, either film or digital one, in order to avoid malfunctions or faults due to overheating. It is obvious that this operation mode consumes lot of battery power, especially for digital cameras. Therefore it is highly recommended to have spare batteries in your bag and to wait some seconds, or few minutes, between successive shoots in bracketing mode, to allow camera electronics to cool down.
When using long exposure times and apertures smaller than F/11, light spots in the scene may produce a star-like pattern in the picture. This effect is due to reflections of light rays on the aperture strips, and differs from lens to lens. A similar effect can be observed in daylight photographies, if a strong light source, i.e. the sun, is included in the scene! Even with very short times and large apertures! Moreover, it is possible to achieve the same effect by placing a star-filter or a net (like mosquito-net) in front of the lens, in such a case the effect will produce a four-pointed star for each light spot, but the image will be soft. I personally do not appreciate too much this kind of effect, because it is quite unreal, but someone may like it.
P.S.: If you use a film camera, it could be useful having a compact digital camera with you, in order to make some test shoots. On top of this paper a picture of mine, entitled "Nel blu dipinto di blu", shooted during the blue time.
Article written by Mambasoft
Thursday, 3 June 2010
Old Photo Effect in Photoshop - Photoshop Tutorial
Tutorial Photoshop: Old Photo Effect.Take a modern, high quality image and turn it into an old, scratched up photo!
Tuesday, 1 June 2010
Microstock yes or no? Thoughts about Microstock phenomenon
An interesting thread on the forum fotografare.com addresses the topic of microstock. The most interesting ideas found there will be discussed in this paper.
Microstock could be a way to earn little cash, but if one wants to “survive” with microstock only, he needs thousands good quality shots, whereas if one wants to earn to a quite good level, it is mandatory to have an archive with thousands of easy salable images, and in my opinion just few photographers could be able to do so.
From an ethic point of view, the microstock phenomenon represents a serous damage to the professional photographers category, while it is a significant advantage for those thousands and thousands of amateur photographers aiming to gain just little cash. It is not a case if the greatest agencies are in crisis, or even already closed, while few giants (Getty, Microsoft), that actually have the control of the microstock market, are growing up, by cutting away those that produce high quality at higher prices.
So, sadly, is the way real world is going on. If you want, for example, a reportage on Zimbawe, you have, basically, two options. You can buy it from an agency, say Grazia Neri, and get very high quality material and contents by paying several thousands euros. As an other option, an easy-prose journalist, who maybe never went in Zimbawe, can quickly write down a reportage and buy 20 shots from Getty, more or less set in Zimbawe, with just few hundreds euros. The latter is photo-journalism as well, nothing different that one can see every day... but Grazia Neri has closed, while Getty sells 20 shots at 150 euros and gives 80 of them to the tourist visiting Victoria falls who, probably spend them in few hours at the hotel casino.
Microstock represents an earnings resource for editors, journalists,and maybe few photographers. While it could seriously damage the culture of image and the culture of well-doing, rather than cheap-doing. May the next step be Chinese microstocks who will sell not for 5 euros, but just for 5 cents?
Moreover, Grazia Neri has really closed, and so done many others. Life has closed too!
We are actually bartering culture with money, quality with money, consciousness with money, and then, with more money we are boying worse quality things and, maybe, we also complain about that. On one hand, we are feeding the microstock market, while on the other hand we complain about “made-in-china” t-shirts: on one side we promptly run to the mall to make our bargain with toilet paper sale, while on the other side we complain there are less and less book-stores in our cities and we do not understand that it is exactly the same phenomena: we complain about something, while in the same time we are feeding it with our everyday choices.
The problem is that we are living in the “low cost” era.
In each market field, from photography, through graphics, to web design, the average customer looks for the lowest price.
The problem is that average customers lack the perception of quality, and this can be either due to ignorance or superficiality. But it is clear the customer target is to spend as less money as possible.
From this point of view, the microstock phenomenon could be a cure-all for advertising agencies which, due to their limited budget, are forced to use microstock in order to contains production costs.
For those who want to explore this field, I suggest to visit the Yuri Arcurs' blog, a guru of microstock, where it is possible to find great ideas:
If you take a look to this website, you will be able to recognize that this guy actually own a sort of microstock industry, with an IKEA-style shed fully dedicated as a set for his shoots.
I believe it would be a reference point for all “microstockers” all around the world.
Article translated by Salvatore Castorina - Photo Album Flickr
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