When I shoot with my camera with many lenses at relatively wide apertures, and try to focus to infinity, (manually, using zoomed live view or otherwise), I find that end result pictures are not focused at infinity. Actually, it can be hard to tell what it is focused at, but I've not been able to obtain focus at the very distant subjects.
I have trouble understanding whether I simply have bad technique, or if the camera body has a flaw. The flaw which I am specifically thinking of is that the lens mount is actually slightly too far ahead of the sensor (or the sensor is mounted too deep). The problem is, through very limited testing, I've noticed this problem with some other cameras (all cheap crops mind).
Can I verify the problem reliably, without sending the camera off to a service centre (warranty issues, cost, etc etc)?
EDIT (for camera and lens info): Camera: EOS 650D Lenses tested: Canon EF 50mm f1.4, Canon EF-S 18-55 f3.5-5.6 IS II
UPDATE: I attach some pictures taken with my cellphone camera to illustrate how the final image is WORSE than the live view result. These were taken using a fully manual lens, wide open @ F/2.8.