ark@rabbit.UUCP (Andrew Koenig) (03/09/84)
A well-designed wide-angle lens does not distort (fish-eye lenses aside). Specifically, straight lines in the subject are rendered as straight lines on film. However, a non-distorting wide-angle lens can cause some pretty strange-looking things to appear on film. This is a necessary consequence of reproducing straight lines as straight lines. The wider the lens, the harder it is to use it without making things look weird, unless you're careful about how you use it. My gut feeling is that the 'average' amateur photographer should be able to handle a 35 mm lens, that a 28 might cause trouble, and that a 24 will almost surely cause trouble. On the other hand, a 35 isn't all that much different from a 50.
kar@ritcv.UUCP (Ken Reek) (03/21/84)
Wide angle lenses do not distort straight lines (not counting fisheye lenses). Any distortion you think you see in the final print is a result of viewing the print from the wrong distance. The distance at which a photograph should be viewed is proportional to the focal length of the lens with which it was made. Take one of those "distorted" pictures made with a wide angle lens and look at it from a distance of a few inches -- if you can focus your eyes that close, you'll find that it suddenly looks fine. The same holds true for the strange foreshortening you see in photos made with a long telephoto lens -- if you view them from a large distance, they look perfectly normal. Ken Reek, Rochester Institute of Technology seismo!rochester!ritcv!kar
smith@umn-cs.UUCP (Richard Smith) (03/23/84)
#R:rabbit:-258700:umn-cs:9000014:000:282 umn-cs!smith Mar 22 17:23:00 1984 I have a 24mm Nikkor and had a very hard time convincing a friend looking through it that he was indeed seeing straight lines. The wide angle effect is very pronounced --- right angles don't look right at all --- so it's easy to see lines as curved even when they aren't. Rick.
kar@ritcv.UUCP (kar) (03/29/84)
In response to Bill Lampeter's statements: > Wide angle lenses certainly may distort straight lines. These distortions are > known as barrel and pin cushion distortions. In fact, such distortions are > not limited to only wide-angle lenses but are often most noticeable in them. > Since wide angle lenses may indeed distort, you can see it in prints. These distortions are present (to some degree) in lenses of all focal lengths. The claim I was replying to, "wide angle lenses distort straight lines", clearly implies that this distortion is a result of something that is unique to wide angle lenses, and not barrel or pincushion distortion. The most apparent "distortions" one sees when viewing a picture made with a wide angle lens are the exaggeration of depth and non-parallel lines. The depth effect can produce geometric "distortions" as well, for example, circles may appear to be elliptical, but all of these are eliminated when the print is viewed from the proper distance. This is almost always too close for comfor- table viewing of prints made with lenses shorter than 35mm, but if you are as nearsighted as I am you will be able to get it close enough for the "distortions" to vanish. The other "distortion", non-parallel lines, is typified by photos of towering buildings in which the walls of the building seem to be falling toward each other. This only occurs when the film plane is not parallel with the object being photographed, in which case the camera is faithfully recording what it sees. With 35mm cameras, you must keep the camera perfectly level when taking pictures of buildings and so forth in order to avoid the "distortion." With a view camera, you would simply raise the lens board so as to include the top of the building in the photograph without having to tilt the camera. I recall reading an article about a camera with a permanently mounted super-wide angle lens for making panoramic photographs. The camera had a built-in level to simplify the vitally important task of levelling it. These two "distortions" can happen with lenses of any focal length, but are most apparent with very wide angle lenses. They are NOT caused by your lens, however. Ken Reek, Rochester Institute of Technology seismo!rochester!ritcv!kar
bill@ur-laser.UUCP (Bill Lampeter) (04/04/84)
In response to Ken Reek's statements: > Wide angle lenses do not distort straight lines (not counting fisheye lenses). > Any distortion you think you see in the final print is a result of viewing the > print from the wrong distance. Wide angle lenses certainly may distort straight lines. These distortions are known as barrel and pin cushion distortions. In fact, such distortions are not limited to only wide-angle lenses but are often most noticeable in them. Since wide angle lenses may indeed distort, you can see it in prints.