at high f-numbers it's going to be harder to get things in focus
This does not make any sense.
Your 450D will stop down the aperture just before the picture is taken, so it doesn't matter if you (or the camera) sets f1.8 or f22
(we're talking about autofocus lenses, right? The finder does not get darker, as you change aperture, right?)
This does not make any sense.
Your 450D will stop down the aperture just before the picture is taken, so it doesn't matter if you (or the camera) sets f1.8 or f22
(we're talking about autofocus lenses, right? The finder does not get darker, as you change aperture, right?)