The 5D pixel size is 8.2 microns and the D70's is 7.8 microns. Diffraction should affect both cameras to about the same degree and other factors being equal I would expect the resolution in LP/mm to be about the same.
I didn't realise the pixel pitch was so close. I guess this is explained by the fact the 5D actually has 12.8MP and the D70 sensor is actually slightly bigger than the Canon D60 sensor, which was my first DSLR. You've got a crop factor of 1.5 there instead of 1.6.
I just checked the resolution charts at dpreview and it seems the D70 does have marginally greater resolution than the 5D. Eg. D70 lines per picture height (LPH) vertically = 1450. D70 sensor vertically = 15.6mm. 1450/15.6 = 93 lines.
93 lines = 46.5 line pairs.
A similar calculation for the 5D gives a result of 42 lp/mm. These are described as absolute resolution figures relatively free of aliasing and moire effects.
One could argue that resolution in the centre of the image could be greater. However, the edge of the 5D frame vertically is only 12mm from the centre. The Photodo MTF charts for the Canon 50/1.4 at f8 show a remarkably flat response at 40 lp/mm all the way to 18mm from the centre, so I think the 43 lp/mm maximum, practical resolution for the 5D is likely to be quite accurate.
What we're left with, it seems, is the practical effect of an increase in MTF across all resolutions below 42 lp/mm as we open up the aperture from f16. This is obviously going to vary with the quality of the lens and one would expect prime lenses to produce a contrastier result.
Why do you think that your lens is optimized for f/16? I would think that the "sweet spot" would occur at a somewhat larger aperture if it is well corrected for aberrations
Just my eyes. That's what my sample images posted earlier in the thread are telling me. The 'sweet spot' is probably still f8, but the differences between f8 and f16 are so small as not to matter.
I must get myself one of those Canon 50/1.4 lenses. I'd forgotten it has such a flat response at 40 lp/mm and f8.
You mention Raw Shooter vs ACR (I use the latter). Is there a significant difference in the resolution that the converters can extract from the file?
Yes. There appears to be; far greater than the 24-105 differences at f8 and f16.
However, perhaps it would be more accurate to say, if one restricts oneself to using sharpening options only available from within the RAW converter, then Raw Shooter does a much better job than ACR. If one is a real whiz at using other sharpening programs and one has a perfected technique of post conversion sharpening, then who knows?