40D Manual Focus Not In Focus

Just got my 40D back from Canon for sensor and mirror cleaning. I shot an air show yesterday and my what I thought was in focus was not while in manual. My auto focus looked out of focus even after adjusting doppler but those photos are in focus.

When I got back to my hotel room I did some test shows using the hotel room key that has text on it. Again, when I focus manually it looks crystal clear through eye piece but images are are not and when I shot auto focus the hotel key did not look clear in eye piece but was clear when looking at image.

What am I missing here to keep images sharp in the eye piece and sharp once shot?

When you are manually focussing, it's often best to use Live View and zoom in on the part of the subject that you want to keep in focus. using just the optical viewfinder makes it very difficult.

The chances are that your viewfinder diopter is out. here's how to set it. Turn your camera on and half press the shutter button so the shooting information appears in the bottom of your viewfinder. Then, look next to your eyepiece. In the top right corner, you'll see a teeny tiny dial, half hidden behind the eyecup. rotate this and it will adjust the focus of the viewfinder. Turn this dial while looking through the viewfinder until the information displayed in it is as sharp as possible.

It definitely sounds as if you have the diopter setting wrong, you need to adjust it until the focus points appear sharp, failing that the focus screen may be out of alignment, if so Canon should fix it if it wasn't like that before you sent it in.

They knocked the focus screen out of alignment. AF uses a different sensor still in alignment.

Sounds like the focus screen is not mounted properly (or otherwise misaligned). Is it sharp with AF and live view?

Yeah, check that the focus screen is fully latched in place. That's most likely the problem. They might have removed it during the cleaning and then not gotten it fully latched, or it wasn't fully secured and came unlatched after they returned it to you.

Not knowing how much they had to disassemble for the cleaning, the pentaprism above the focus screen and the frame that mounts the focus screen are very precisely shimmed for accurate positioning. If any of that had to be taken apart during the cleaning (not likely, but remotely possible) and were reassembled with incorrect shims or without shims at all, it also would throw the viewfinder image out of whack.

But I'm betting it's just the focus screen. That's far, far more likely.

After checking the focus screen and reseating it, redo the diopter setting (as Fitzer describes, though I'd add that I find it easiest with no lens on the camera or with the lens thrown completely out of focus during diopter adjustment).

If this doesn't work, I'd be talkin' to the folks who did the cleaning about the problem!

Thanks to all for your comments. Very helpful and much appreciated!

Called Canon and they agree sounds like focus screen so sending back for the repair.

The focus screen is user replaceable on the 40D. Take it out and put it back in to see if it helps.

Uh-oh, on second thought, if you don't have another focusing screen you most likely don't have the special tool for handling it either. Then it may be better to send the camera back in.