Archived posting to the Leica Users Group, 2001/11/05
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I was at the Photo Expo in New York on Friday. Canon had an interesting digital photography exhibition. They stuck a model in a small studio setup, gave a photographer a D30 (Canon's "consumer" digital SLR, of modest specs), and started taking pictures. The D30 does not use special lenses; it uses EOS lenses. The photographer was using the 28-135mm zoom. Moments after the picture was taken, it was transmitted to large video screens for the audience to see. The photos were then printed out on one of Canon's high-end wide-paper printers. They came out poster-sized, perhaps two feet by three feet - larger than anything I'd try with a 35mm camera. They passed the prints around; the prints were beautiful - lovely color, lovely contrast, nice sharpness, even from very close up. The photographer explained that he was using only jpeg's, and not RAW or whatever images. The guy printing the stuff out said all he did was about 30 seconds worth of Photoshop work - a little resize, a little crop, a little sharpening. I'd like to be able to do this with my M camera, or something similar. But you're right, in the end the pictures had all these false pixels and stuff. It was awful. I can't believe they went in public and humiliated themselves with that technology. Really appalling. C. http://www.availabledark.com - -----Original Message----- From: owner-leica-users@mejac.palo-alto.ca.us [mailto:owner-leica-users@mejac.palo-alto.ca.us] On Behalf Of Jim Brick Sent: Monday, November 05, 2001 12:40 PM To: leica-users@mejac.palo-alto.ca.us; leica-users@mejac.palo-alto.ca.us Subject: [Leica] Re: Re: Vs: digital At 06:56 AM 11/5/2001 +0000, George Day wrote: >"not compatible"? Whatever. Seems to work just fine for the well over >90% of photojournalists shooting Nikon and Canon digital. I'm sure it >would be quite adequate. These are lenses, not spiritual beings. Unfortunately, George, you are not aware of the technology involved in digital sensors and lens resolution/MTF frequencies. Instead of me attempting to explain all of this to you, go to: http://www.schneideroptics.com/white/kina.htm and see why Schneider (and Rodenstock, and others) make lenses DESIGNED FOR digital sensors. Then go read about the Nyquist limitation at: http://www.opus1.com/~violist/help/nyquist.html Nyquist's theorem: A theorem, developed by H. Nyquist, which states that an analog signal waveform may be uniquely reconstructed, without error, from samples taken at equal time intervals. The sampling rate must be equal to, or greater than, "twice" the highest frequency component in the analog signal. In terms of lens resolution on digital sensors, it means that there must be at least twice as many pixels per mm as the maximum resolution (lp/mm) of the lens. If this is not true, the information gathered will be either partially or completely in error, and always aliased. See figure 4 in the Schneider white paper. Modern Leica lenses have more resolution than can be handled by digital sensors. They cannot make pixels small enough to be at a frequency twice that of the resolution of Leica lenses. Five square microns is about the limit of a pixel that can record enough light to produce a quality dot. And don't forget that it takes four pixels to record a single COLOR dot (pixel). The problem is that folks who do not understand the limits of digital electronics vs analog signals are moaning and groaning as to why Leica doesn't get with it and produce a digital M mount camera. They could certainly OEM a high level digital camera and put an M mount on it. But why? They would also have to but a resolution reducing filter behind the lens in order to produce good digital photographs. So why bother? The Panasonic Leica digital camera soon to be on the shelves has a Leica lens which is specifically designed to match the resolution capabilities of the digital sensor. There is no full size digital sensor made with a pixel size small enough to take advantage of Leica lenses. Actually the reverse is true. Leica lenses will cause the recording of false information via these sensors. There is certainly more to it that simply bolting an M lens on to a camera containing a digital sensor. Over and out! Jim - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html