From: "Berry Ives" <[EMAIL PROTECTED]> >>>>>>>>>>>>>>>>>
Your math is good; I got 26.2 degrees off vertical. But I don't know the significance of that angle with respect to the sensor "tunnels". It sounds like a rather large angle to me. <<<<<<<<<<<<<<<<< You might do the math for, say, the Contax G-series 21mm Biogon<g>. (The rear element of the Biogons tends to be practically touching the film, as I understand it.) Anyway, I've heard from two people who have tested the 5D sensor for sensitivity vs. angle of incidence, and both found that the falloff was less than with film. >>>>>>>>>>>>>>>> Regarding the issue of (individual) lens-specific info being passed from the lens to the image file, for Olympus (from their web site): "Each Zuiko Digital Specific Lens also contains its own CPU to further solidify a richly colored, clear image. These "smart" lenses transfer data specific to the lens being used to the system's software to correct potential distortions and aberrations that occur in all lenses. Pin cushioning, barrel distortion, shading and other unwelcome phenomena can be eliminated with the single touch of a button in software." <<<<<<<<<<<<<<<<<< The 4/3 sensor is 1/4 the area of the FF sensors, and not really a serious format. If one is concerned with image quality. Meanwhile, the lens name makes it into the EXIF information in most SLRs for most lenses, and some software will do the corrections for you, with some of it automated, I think (PTLens). I haven't found the need for any of that with either the Sigma 12-24 or the Canon 17-40 on the 5D, although I mostly shoot stopped way down. The place that I do need some correction help is the 24TSE (which needs chromatic abberation correction when shifted), but the amount of shift and tilt doesn't make it into the EXIF data, so it can't be automated. Oh, well. I really ought to CLA the Nikon 8000, pick up a cheap EOS film body, and do the work. But there's real work in the inbox, a guitar to be practiced, old photographs to be processed, and new photographs to be taken... David J. Littleboy [EMAIL PROTECTED] Tokyo, Japan ---------------------------------------------------------------------------------------- Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body