Originally posted by loco
I understand that a full frame sensor will result in less DoF than I'm used to with my various APS-C bodies. So, I imagine for landscapes I might have to shoot at f/11 rather than f/8. In some cases, I might even need to go to f/16. So, does the full frame sensor change anything when it comes to lens diffraction? Usually, in most cases I would not use f/16 for fear of diffraction making the photo less sharp, so this is a little bit of a concern. Thanks for any input!
Basically you'll get the same diffraction on FF but one stop more closed down than on APSC... And to get the same deph of field, you'll have to close down one stop more. Conclusion: Diffraction will not have more effect than on your APSC body.
As for printing, the 16-24MP of an APSC body are more than enough to print 30x40" with great quality and that likely bigger than what most people are ever going to print anyway. You'd see a small difference difference if you print 30x40" AND you stare at the small details from near distance. Because well 24MP at 30x40" is "only" 150dpi while 36MP would be 183dpi... The difference not that big.
As a point of comparison, a full HD 24" computer screen is 91dpi while a 15" full HD laptop screen is 150dpi. Imagine this level of detail over 40"... That's what a K3 give printed.
The thing is other aspects will affect your pictures much more than diffraction. Camera shake, blur from movement, high iso settings, focus a bit off, insufficiant shutter speed... Ligting condition and flare. All theses things will have several order of magnitude more impact on the technical aspects of
your picture than the diffraction if you keep it safe no more than f/11 on APSC and no more than f/16 on FF.
And of course actual light quality, subject interrest and composition still matter infinitely more than the technique as long as it is good enough. That's actually what make a great photographer for me: hability to make interesting picture in all kind of conditions... Make hugly people look nice, old people look less old, make an un-interresting place shine...