Re: [Leica] Re: Re: Vs: digital

[George Day <george@rdcinteractive.com>]

Jim,

Been there, done that and, ahem, own some of those lenses.  That's right,
4x5 digital.

But we're talking about hand-held street photography here, my friend, not
high-precision architectural or product photography.

And, please, don't presume to be so much better informed that someone you
haven't met and whose background you don't know.

on 11/5/01 5:40 PM, Jim Brick at jim@brick.org wrote:

> 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

- --
To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html