Archived posting to the Leica Users Group, 2005/09/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I'm not an expert on it; but I know that film grain has much more tolerance concerning the angle of the incoming light, than sensors usually have. In the centre of the sensor, the light is captured in the ideal 90 degrees angle, but the more you go to the corners, the more this angle is increasing, and the quality too (like a kind of softness-vignetting). The problem occurs with non-retrofocal wide angle lenses more than with retrofocal lenses. The 4/3 system* for instance, and many other digital lens manufacturers, are trying to evitate this problem with new retrofocal lenses. AFAIK, the new Zeiss ZM lenses are built this way, too The disadvantage about this lenses is that they're less compact than the non-retrofocal ones - and the small lenses (compared to SLR) have always been an advantage of rf cameras. Didier * See http://www.four-thirds.org/en/about.html and click Flash or PDF Version. It is explained how the light angle is affecting the sensor. >How does this affect the plane of focus, where the sensor presumably sits, >especially compared to film? >Frank Filippone >red735i@earthlink.net > >I dont have this lens, but assuming that you did not have this problem on a >Leica film camera, I think the phenomenon is known. With wide ange lenses, >the angle of the incoming light to the edges of the sensor is much less >than the ideal 90? degrees. So it might be a sensor problem not a lens >problem. >Didier