Digital M/Digital Rebel was Re: [Leica] Lost Faith in Leica

[jonathan at openhealth.org (Jonathan Borden)]

Nathan Wajsman wrote:

> Peter Klein wrote:
>
>> Jim:  I have no examples.  It just follows logically.  On humble Web
>> Jpegs, I can see drastic differences, wide-open or nearly so, between 
>> the
>> 35 'Lux asph and its predecessor, or even the pre-asph 35/2 Summicron
>> wide-open.  Even the humble 3 megapixel 1/1.8 sensor on my Nikon 
>> Coolpix
>> 990 can resolve greater detail than can be shown on a Web jpeg, so I'm
>> certain a 6mp DSLR can show it, too.  Ergo. . .
>> Also note that Nathan (and others) have noted that they can see the
>> difference on Canon DSLR shots between their Leica R lenses and the 
>> Canon
>> or Sigma lenses.
> Peter is right. The difference is clear. I don't care what the science 
> says, I don't know about what kind of anti-aliasing filter or whatever 
> my Canon 10D has. But I do know that when I put the 100mm Apo Macro on 
> it I get better pictures than I do with the Canon 85mm lens (which is 
> no slouch either), and when I put my newly aquired Canon 17-40mm L 
> zoom on it, the pictures are much better than those I got with the 
> (now sold) Sigma 17-35mm. All this talk about how with digital sensors 
> lens quality does not matter is bunk, based on my experience.

Oh I started this I believe, when folks were asking whether increasing 
the pixel count from 6 mp to 16 mp would make a difference.

I certainly see the difference in quality with better lenses ... my 
point really is that if you do care about such quality and if you are 
willing to shell out the $$$ for such lenses, then you ought capture as 
many as possible of the pixels such lenses are capable of resolving.

The other point is that for low res web images, you can do lots of 
things in Photoshop (essentially multiple unsharp masks with different 
parameters) to increase the local contrast of the image -- this often 
mimics a higher quality lens, with the downside of introducing some 
digital artifact not easily see in low res images which already have 
JPEG artifact.

The "Ergo..." above just isn't true for technical reasons. To consider 
*any* image you need to look at the whole chain, from fog in the air, 
to the lens, to the sensor, to the output. All I am saying is that the 
lens is an important part of the system and so is the sensor. A low 
pixel sensor just isn't capable of capturing the same higher order 
harmonics as an otherwise equivalent higher pixel count sensor. That is 
a fact.

An strong analogy to the above argument is the argument that a  CD is 
capable of capturing all the sonic information of an LP because the 
human ear can't hear more than 20 khz at best ... sure if you are 
playing a boombox. Most anyone who has a super high end system can 
demonstrate this not to be the case ... assuming the recording is of 
high quality. One of the primary problems is that the CD sampling 
frequency just isn't high enough (44 khz) and *double* turns out not to 
be enough... Ergo... DVD-A is up at 192 khz. Its all about harmonics. 
For the same reason pixels do count.

Jonathan