shirozina wrote:
The issue is greatest with wider lenses as they have the smallest depth of focus ( not to be confused with depth of field) so any manufacturing error in the lens or lens flange and sensor with regards to being non parallel will easily show. Depth of focus increases as the focal length increases so telephoto lenses can tolerate a non perfect parallel assebmly of the sensor and lens flange a bit better. As sensor density goes up - all this stuff gets more important.
Actually I believe depth-of-focus is independent of focal length when you\'re focused to infinity. The formula according to wikipedia is
The magnification M depends on the focal length, however for objects at infinity the magnification is zero taking focal length out of the equation. It often seems like wides have shallower depth of focus at infinity but I don\'t see how this can be the case unless the formula above is incorrect (I don\'t happen to have the text book it\'s reportedly from).
shirozina wrote:
The issue is greatest with wider lenses as they have the smallest depth of focus ( not to be confused with depth of field) so any manufacturing error in the lens or lens flange and sensor with regards to being non parallel will easily show. Depth of focus increases as the focal length increases so telephoto lenses can tolerate a non perfect parallel assebmly of the sensor and lens flange a bit better. As sensor density goes up - all this stuff gets more important.
Actually I believe depth-of-focus is independent of focal length when you\'re focused to infinity. The formula according to wikipedia is
The term v denotes the image distance which tends to zero as the focus distance tends to infinity, thus taking the focal length term f out of the equation. It certainly seems like wides have shallower depth of focus at infinity but I don\'t see how this can be the case unless the formula above is incorrect (I don\'t happen to have the text book it\'s reportedly from).
Aug 05, 2015 at 06:19 AM
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