[Leica] Interesting info for digitographers

[douglas.sharp at gmx.de (Douglas Sharp)]

In the latest issue of ColorFoto (Germany) there's an interesting 
article about the limitations of digital cameras at certain lens apertures.
It's all to do with refraction and pixel sizes, Airy disk size or 
Fraunhofer circles of diffraction - the main article is pretty much 
physics/optical theory but the list of cameras and limiting apertures is 
interesting.

What it boils down to is - it's not worth stopping down to get a sharper 
image any further than the apertures shown below, it just won't increase 
sharpness, in fact it will get unsharp.
(NOT DOF, that, of course, will increase)

Camera/aperture
Canon EOS 1Ds Mk II  11.8
Canon EOS 1D Mk II    13.4
Nikon D70                      12.9
Fujifilm S3 Pro               12.5
Canon EOS 20 D            10.6
Sigma SD10                    15.0
4/3 cameras                     9.0

And it gets worse for compacts.

It finally explains why my macro shots with f16 were not as pin-sharp as 
those with f8.
Douglas