On-line DOF Calculators such as

http://www.dofmaster.com/dofjs.html

will give you an idea of what f-stop is required for a given focal length lens, subject distance and sensor size.

Interesting link Rob. Just the time to bring in "circles of confusion"! :D

Somewhere I am sure there is a thread where we discussed this as I have dug up a full frame pic and composite of a crop at various apertures. Probably taken shortly after I got the D2X and was doing some tests. Diffraction limit is affected by pixel pitch. The smaller the pitch the sooner diffraction kicks in. To compare you sensor with the one that was used here I have dug up the relative sizes.

D2X sensor size 23.7 x 15.7mm with 12.4 mp. Pixel pitch 5.5 um
Olympus E-PL1 sensor 4/3" size 17.3 x 13mm 12.3 mp.

As the Olympus has pretty much the same number of pixels but on a smaller sensor, the pixel pitch will be smaller. So a rough guide translating the attached composite would require you to shift the shown f numbers right by one column for a similar amount of softening. D2X at f8 might equal the Olympus at f5.6.

Don

PS : I do remember doing a similar test subsequent to this with the 6mp D100 and concluded its diffraction limit was f16.
Ha,ha found this in Cambridge in Colour so there is a thread somewhere
http://www.cambridgeincolour.com/tut...hotography.htm