Question about sharpness/autofocus

So here's a question that even after 3.5 years of playing around with lenses, I can't figure out.

If I'm shooting wide open on my zooms, at f/2.8, and my sharpness seems to take a hit when I shoot faraway things compared to close up maybe under 5 - 8m, does it mean that it's my AF adjustment that is off?

Zexun

Headshotzx wrote in post #13154937
So here's a question that even after 3.5 years of playing around with lenses, I can't figure out.

If I'm shooting wide open on my zooms, at f/2.8, and my sharpness seems to take a hit when I shoot faraway things compared to close up maybe under 5 - 8m, does it mean that it's my AF adjustment that is off?

Not necessarily. But you have a 5d2 so you can test that by shooting a 2nd shot using liveview focus, make sure the focus is spot on, and compare the shots.

Distant shots can often appear softer. You're shooting through a lot more atmosphere - heat waves, pollution, etc all soften the image.

which lens and how far away, and how much cropping? atmospheric conditions as well as hand shake can come in to the equaiton.

I agree - more air noise to shoot through. All settings being equal, the further out your subject, the larger your depth of field (acceptable sharpness) will be, and less likely it would be that you would notice an AF issue. Do you find that stopping down brings you sharpness that you would expect?

I agree that there's loss of detail at distances due to atmosphere.... And, yes, slight camera movement is more obvious, the greater the distance. Also some of it is due to lower micro contrast at distances (again, an atmospheric effect), which makes things appear less sharp. Some of it is just that the further away things are, the less detail you (or the lens/camera) can see.

But also you state you are using your zooms wide open at f2.8. Try stopping down a bit to improve them. I try to use f4 to f5.6 most of the time. There are some lenses that are incredibly sharp wide open (Canon 300/2.8 IS is one), but even they perform best at closer distances. And, unless you are going for really shallow DOF for some reason, there are few reasons not to stop down a little whenever light allows.