? XT misfocussing with 50mm f1.4 lens

I understand that an XT can have problems getting accurate focus with any lens with a maximum aperture of f2.0 or wider. Will autofocus then be less consistent with a 1.4 lens than with a slower lens such as the 50mm 1.8? I've got an XT that focuses well with a 50mm f1.8, but I just got a 50mm f1.4 which seems to show much more inconsistent focus.

The AF build on the 50 1.4 is better than the build of the 50 1.8. The AF should be better with lenses that have wider apertures due to the len getting more light to the AF sensors.

Yup, larger aperture=better focus.

I just sent my Rebel XT to canon to see if they can get the focus right on my 50mm f/1.8 II. It hasn't made it to them, but I will keep you guys updated. I tried a focus test over and over again and it would front focus almost a 1/2 inch forward. You never notice until you use a really large aperture lense. The nifty fifty is a perfect example to find out. Hopefully they solve my problem. My camera is under warranty for like two more months.

I think your understanding is reversed; generally the camera will have less trouble focusing reliably with wide apertures than with smaller ones. However, the 350D doesn't, I believe, have the increased-sensitivity center AF point(s) of the higher-level EOS models and the 400D. This kicks in on lenses of f/2.8 or faster maximum aperture so, again, it's the opposite of what you're describing.

Jon wrote in post #3050896
I think your understanding is reversed; generally the camera will have less trouble focusing reliably with wide apertures than with smaller ones. However, the 350D doesn't, I believe, have the increased-sensitivity center AF point(s) of the higher-level EOS models and the 400D. This kicks in on lenses of f/2.8 or faster maximum aperture so, again, it's the opposite of what you're describing.

I agree with Jon here. The problem that some poeple are having is a miss calibrated camera from the factory. You should definitely have ean easier time focusing in super wide aoertures. Like I was saying, the DOF is so small at f/1.8 that it is much easier to notice exactly where the focus is based on the very shallow amount of focus you have.

I sent my camera in and will hopefull hear back in about a week with how it is. My camera wasn't bad,but I noticed at super wider apertures, it was front focusing. I just want to make sure the camera is rock solid while it is still under warranty. I will be using is as a solid backup so day or giving it to my fiance.

When I shoot, I primarily have my focus points set to just the center focus point. I like having that control. I don't like having the camera guess the focus pooint unless it is AI Servo and then you hope it focuses right. Most of the time no problem.

Now don't get me wrong in thinking that there is some huge problem with the Xts. There is not. In fact I love my camera. Especially with the grip. I don't think I could ever go back to using it withou a grip. What A difference. Anyway, I am gettting off topic. I hope some of this helps a little.

Do a controlled focusing test with your camera and lens. If it's front/back focusing then you need to send it in for repair. If not then it's just a matter of getting used to the lens. f/1.4 has such a shallow DOF that it's hard to hit proper focus on any camera. Try shooting at f/2.8 or f/4 and see if you are still having problems.

That said, of the current cameras available (new) the XT has the oldest and worst focusing system. With my 300D (same system) I had a lot worse luck trying to get my 50 1.4 to hit accurately. Maybe 1 in 10 shots were good! Now with my 5D is practlly reversed (9 of 10 are keepers) although the DOF is still EXTREAMLY shallow.