Not in the Minolta/Sony mount, though.
Not much more than removing all extra gearing.
The latter has extra elements for more correction. Note that Sigma has vignetting issues and a linear drop of vignetting, none of these in the 35G.
Not really. The ground aspherical element, SLD and ELD glass do take their toll (none in the 50 mm lenses, apart from 50/1.2 L and 50/1 L by Canon), as does build quality.
I was appalled when I learned that typical focal lengths in camcorder zooms started at about 40-45 mm equivalents, 38 mm was very rare indeed. But filming is quite a different experience and indeed, 40 mm in motion pictures seems wider than 28 mm in still cameras -- a lot to do with optical illusion and the fact that the brain has more data to work on in a moving image than in a still one. Indeed, this can be seen in everyday lives -- hustling through a busy street and your field of view is limited -- you focus on a very narrow cone in front of you. Slow down, move when the street is less busy and you see more detail around you. Stop, look at night, and you have a wide vista.
I'd be interested to see your examples. You might try posting your pictures on photobucket or pbase etc in order to share them here.
You seem to be talking about angle of view, not perspective. Perspective has to do with how objects relate to each other: is one in front of the other, or beside it, partly to the left, partly to the right, etc. Of particular interest for conventional (2D) photography is relative size as an indicator of distance.
You're right but your example is wrong. A 200mm lens at 100 ft is the same as a 20mm lens at 10 feet. You're cropping example won't work since perspective changes with the distance from the subject.
No. I'm not sure what theory leads you to think this way. It is not supported by a practical test. Try it and see.
Compressed perspective arises from viewing all of the subject from further away.
That makes no sense at all, I'm sorry. "From the same location". Cropping has NOTHING to do with changing the camera position.
They are interesting examples, as long as it is clear that the camera has moved. The author states:
No. It's called the "50mm myth". It's basically bogus. Do a search on that term.
Perspective is solely a function of location, not focal length. This has been mentioned in the thread before. Look at this site's glossary on perspective.
I hope the answer to this is now known.
Go read the glossary article.
Look through a camera with a 50mm-equivalent lens mounted. Note the field of view you can see. Now move the camera away and look at the same spot. Note your field of vision.
No they dont. Cropping doesn't change the angle of view. It only restricts what you see with the same angle of view. Cropping is like looking through a 6" square hole cut in cardboard held at arms length. It doesn't change the angle of view. The 200mm at 100ft has the same angle of view as the 20mm lens does at 10 ft. Increasing focal length increases the angle of view which has the effect of visually bringing you closer to your subject.
If we are thinking in terms of the 35mm film format, the 200mm lens has an angle of view of about 12 degrees. A 20mm lens has an angle of view of about 94 degrees.
Cropping changes the angle-of-view by definition. The angle of view is the angle between the left and right (or top and bottom, or corners) of the image. Cropping moves the borders and therefore definitely changes the angle of view.
That's field of view, not angle of view. The field of view is the actual size of the focus plane, and indeed it is the same as you described above.
Increasing focal length decreases angle of view.
Yes, they do. That is often the best argument against "focal length compression". Ask people if they notice that the perspective relationship between two objects (lamp, tree, two people, whatever) changes as they move closer or farther away while looking at them without a camera. Then ask them if they thought that the focal length of their eye had changed.
