Digital BW, The Print

Ernst Dinkla wrote:
>
> pr_roark wrote:
> 
> > At any rate, I'm impressed with Photozone, although 
> > I hope they start 
> > testing on full frame Canons also.
> 
> Part of their problem is that they like to keep correlation 
> between all the lens test results so the relative old Canon 
> 350D is still used, even for the latest lenses. ...

I would think that consistency would be most important for lens 
tests.  So, using the same camera body -- even if old -- makes a lot 
of sense.  The question then is whether the tests remain relevant for 
the newer, better cameras.

As the cameras get better, I'd think we'd see the differences among 
lenses magnified, but I wonder if the relative performance changes 
much.  The Photozone tests, as well as my own using the 8 mp Rebel, 
can see some of the results of diffraction limits in the center from 
f5.6 to f8 (and more as we go to smaller f-stops).  So, even with 
older camera designs we're seeing some changes (for example, f5.6 to 
8 central sharpness) that are probably not going to be relevant to 
actual shooting.  I don't hear many photographers complain of f8 
diffraction being a serious limit.

As a practical matter, the lenses I was looking at are all very good 
in the center at f5.6 - 11.    

The edges and larger larger apertures are where the action is, and 
there the image quality can look bad even with the older cameras.  
I'd guess it's just going to be that much more worse compared to the 
central image at f8 with the newer cameras. 

On the other hand, I wonder if some of the color fringing at the 
edges is due to sensor design as well as lens aberrations.  I don't 
recall the color fringing being such a big deal with film.  The Canon 
90 TS is the only lens I have that doesn't show that annoying defect 
on both the Photozone tests and mine.  If fringing -- particularly 
with wide angle lenses -- is, in part, a camera defect, they we might 
have some changes that alter relative lens performance.

Paul
www.PaulRoark.com