View Full Version : Apo Digitar

Martin K
16-Apr-2008, 22:40
Could anyone tell me what exactly are the differences between the Schneider Apo Digitar lenses that are "made" for digital and other lenses that are not?

Emmanuel BIGLER
17-Apr-2008, 01:35
Hello from France
Schneider apo digitar lenses were first introduced with the first scanning digital backs covering something like the 6x9 format. Since, I assume that the product line has been re-worked to take into accounf new high performace one-shot digital backs covering about the same surface as 6x4.5cm on film (actually, the sensor area is somewhat smaller, 37x49mm).
By comparison with film lenses of the same focal lengths, "digital" lenses have a smaller image circle but a better performance at the centre.
There is something technically subtle, i.e. the residual lateral chromatic aberration.
Those residues of aberrations were not annoying for film use, they became a nuisance with bayer-type of silicon sensors.
Quasi-symmetric view camera lens designs are by symmetry well immune against those residues, but Schneider and its direct competitor Rodenstock have refined their designs on this aspect. Schneider claims that the residual lateral chromatic aberration in some of their last digital lenses is a small fraction of a pixel only, hence invisible
My understanding is that you can use film lenses with a digital sensor except if you discover that you get unacceptable color fringes in the corners.
Conversely you can use a digital lens with film, you'll get less image circle hence less freedom for tilts & shifts but performace at the centre should be outstanding.

Martin K
17-Apr-2008, 02:46
Wonderful answer. Thank you very much. That explains a lot.