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#31
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What is this weird hatred of different focal lengths?
RichA writes:
On Sep 11, 3:19Â*pm, David Dyer-Bennet wrote: Rich writes: Alfred Molon wrote in m: In article c78ea956-44cd-4f57-80b8-85ef06d59896 @u19g2000yqo.googlegroups.com, RichA says... On Sep 9, 1:43Â*pm, David Dyer-Bennet wrote: "Trevor" writes: Which is all rather amusing when you consider the more serious photog raphers used an 85mm lens and a 35mm lens combination far more often than any thing in the 40-70mm range. If anything a 58 mm lens was a little better fo r portraits than a 50mm one at least, even if not by much. A fast 50mm is a much better lens now on a non FF sensor DSLR however IMO. A 58mm is great on a 1.5X DSLR for portraits :-) But does it behave the same way as say an 85mm on a FF for the same subject matter? Why shouldn't it? The only issue might be the different DOF. How about the flattening effect (compression) of the focal length? Â*m4/3 and 50mm versus FF and 100mm, for instance. Â*Same effective area coverage but would it look different, even if DOF was compensated for by using different apertures? Thre is no flattening effect or compression caused by focal length. Perspective (which technically means the relationships between objects in the rendered image) is controlled by camera location. Â*If you take a photo from the same place with the center of the frame pointing exactly the same direction with a 24mm lens and 600mm lens, and crop the 600mm angle of view out of the center of the 24mm image, the perspective will be the same. So, if we have two objects in a frame, at different distances from the camera and we just frame them in a 500mm lens and then a crop from a 50mm lens shot, the appearance between the two subjects in the images will appear identical in both shots? No "telephoto compression" will be visible making the two objects in the 500mm crop seem closer to each other? Exactly; if the 500mm and 50mm shots are taken from the same location. A "place mat" showing this (pictures taken with every lens a particular manufacturer made, all from the same location) used to be standard furniture at every camera store, too (usually one from each major lens manufacturer, in fact). With a modern wide-range zoom it's very easy to take your own test photos to compare yourself. -- Googleproofaddress(account:dd-b provider:dd-b domain:net) Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info |
#33
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What is this weird hatred of different focal lengths?
David Dyer-Bennet wrote:
The composition will be the same. That is, the size of the two object will have the same relationship. If the nearer object appears to be twice as tall as the far one, that will be true for both images. That's called "perspective", though, not "composition". Perspective is an aspect of composition. The composition will be the same is because there is no change in the perspective. What I said was precisely correct: the composition will be the same. Composition relates to how the objects, masses, colors, and such interact visually to make a more or less pleasing picture. Composition is *not* how things relate "to make them visually pleasing or not". It is "the spatial property resulting from the arrangement of parts in relation to each other and to the whole" (WordNet's definition). Whether composition affects how more or less pleasing an image is it is incidental the definition. Perspective is the size and position relationships of the objects in the picture. Hence it clearly affects composition. -- Floyd L. Davidson http://www.apaflo.com/ Ukpeagvik (Barrow, Alaska) |
#34
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What is this weird hatred of different focal lengths?
On Sat, 15 Sep 2012 20:31:36 -0700 (PDT), RichA wrote:
So, if we have two objects in a frame, at different distances from the camera and we just frame them in a 500mm lens and then a crop from a 50mm lens shot, the appearance between the two subjects in the images will appear identical in both shots? No "telephoto compression" will be visible making the two objects in the 500mm crop seem closer to each other? Any lens, within limits, will project an accurate image of the scene coming through it. The only thing the focal length does is determine the final size of the entire image. If you keep this in mind, you should see that if you crop any part of the scene, you will end up with the same image regardless of the lens you use, and how you crop it, either by sensor size or by post processing. I proved this to myself a few years ago using a 500mm and a cropped 50mm shot of the same scene. I had the comparison up on the web for a while. A similar thing can be seen if you take an extreme wide angle lens, and take a picture of a city, for example. All of the buildings will appear to be curved and lean together, but if you crop out a very small part, you will be surprised to see perfectly rectangular windows. Lots of effects seem to depend on the large final image, not small parts of it. |
#35
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What is this weird hatred of different focal lengths?
On Sat, 15 Sep 2012 20:19:53 -0700 (PDT), RichA wrote:
Modern optimization. No need for outsized image circles now because new glass and curves mean image quality at the lens edge is good enough with a smaller image circle. As you said, it has no bearing on the angle of specific parts of an image on the sensor, which (if the focal lengths were the same) would be the same. One interesting thing I found is that with a DX type lens on my D700, I could force the camera to use the full FF mode, and then crop a perfect square from the image, gaining slightly in pixels compared to the factory standard 3x2 aspect. I like the 1x1 because you don't have to rotate the camera! 1x1 aspect seems to be coming back from the old 2 1/4 days, my Panasonic also has a 1x1 option. |
#36
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What is this weird hatred of different focal lengths?
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#37
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What is this weird hatred of different focal lengths?
wrote in message ... A similar thing can be seen if you take an extreme wide angle lens, and take a picture of a city, for example. All of the buildings will appear to be curved and lean together, but if you crop out a very small part, you will be surprised to see perfectly rectangular windows. Not "perfectly rectangular windows" at all, but if their size is small enough the distortion becomes difficult to see. It is impossible for the building to be "tilted" and it's windows not to be. (Well before manipulation in PS anyway! :-) Trevor. |
#38
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What is this weird hatred of different focal lengths?
On Mon, 17 Sep 2012 12:16:37 +1000, "Trevor" wrote:
wrote in message .. . A similar thing can be seen if you take an extreme wide angle lens, and take a picture of a city, for example. All of the buildings will appear to be curved and lean together, but if you crop out a very small part, you will be surprised to see perfectly rectangular windows. Not "perfectly rectangular windows" at all, but if their size is small enough the distortion becomes difficult to see. It is impossible for the building to be "tilted" and it's windows not to be. (Well before manipulation in PS anyway! :-) Trevor. OK lets say the windows aren't as 'wonky' as the entire image suggests! When I first used a very wide angle lens to take architecture pictures, I thought they wouldn't be usable as scale examples, but small sections of them were surprisingly linear. |
#39
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What is this weird hatred of different focal lengths?
On Mon, 17 Sep 2012 02:57:01 +0200, Mxsmanic wrote:
writes: Any lens, within limits, will project an accurate image of the scene coming through it. The only thing the focal length does is determine the final size of the entire image. Not quite. Focal length determines the field of view that will be projected onto the film or sensor. You're just looking at it another way... if you didn't have a camera but just 2 lenses of different FL, you would see they project different size variations of the same scene... A picture of a house for example might project 2 inches wide with one lens but 3 inches with the other. |
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