Quote:
Originally Posted by gregbradley
I am thinking what I am hitting up against is the Stan Moore's F ratio myth where he basically concludes its not Fratio but aperture and actually shows several CCD shots at different F ratios and the star looks the same.
Its a similar argument with DSLR lenses where full frame and APS equivalence of F ratio of a lens is the same ie. an F2.8 lens is F2.8 on either system. It creates lots of arguing posts for both sides.
Greg.
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I think that these issues are encapsulated in the equation. I could provide a critique of Stan's paper, but it wouldn't add anything. However, you might ask yourself why the image scale is almost the same in his two images, when one was taken at 2630mm fl and the other at 820mm. You might also ask under what circumstances changing the fstop on your DSLR lens from f2.8 to f11 would actually make no difference to the image quality.
An f2.8 lens remains so regardless of where it is. Full frame chips may have larger pixels, so there will be a sensitivity difference due to that.