Focus problems w/ 20D

I've gone through an abundance (at least for me) of lenses. I've tried to improve the quality of lens with each purchase. Unfortunately, my shots are continually soft. Here are my lenses that I think should produce tack sharp images.... Tamron 17-50 f/2.8 / Tamron 28-75 f/2.8 / Canon 100mm Macro / Canon 70-200 F4 L.

Normally, I'd think it's the lens or my unsteady hands, however most shots are on a tripod with the shutter release. I can't see how it's the lenses since I'm taking every precaution to steady the camera.

Has anyone had any problems with the 20d focusing? They're pretty good, but not as sharp as I know they can be. I bought the L lens from a friend and know it produces tack sharp images, but on my camera, they seem to be just a hair less than tack sharp.

Any ideas??

Got images. I guess you might send the stuff in for repair if it's that bad.

I guess that many lenses can't go wrong. I'd blame the camera body instead. It could be a back- or front focussing issue. Download a focus test chart, print it out and do a test.
A simple method is to take a picture of the keyboard at an angle (from left or right) aiming at letter G, camera set to widest aperture. But you can use a newspaper too.

Try some shots using manual focus. If this will turn out ok then I think your camera has a front or back focus problem. Under the mirror you should find a tiny screw for adjustments of the focus if you want to try to solve the problem by yourself. But my recomandation is to take the camera to a Canon service, where they will readjust it using profesional equipment

Thanks all. I'll download the test and try it out. I've got a local camera dealer I can take it to if needed. Thanks again.

I'll also try the same lenses on my 300 to see if there's a difference.