Focus Issues

[bardya]

I am pretty much an amateur. I am having focusing issues with my camera. For the past few shoots, I have used a large aperture. But for some reason, the left side of the picture is put of focus. Everything else is fine and sharp, but the left side just doesn't work. I used the center point for focus and used the 18-55mm kit lens.



This is an example. The left headlight is out of focus. The main focus was on the Mazda logo.
Yesterday I took a picture of a group of 4 people. The leftmost person was out of focus while everyone else was sharp.

Please tell me my camera is not out of whack.

What seems to be the issue?

Or is it just bad composition.

[oldwolf]

what's the exif data on this?

do you get the same issues with your other lens?

filter or lens has a smudge on it?

[bardya]

No smudge on the lens. there was a fingerprint on the filter, but very light. on the same side. but still i don't think it was that noticeable. i have cleaned the smudge, will look to see if it happens again, but i still think that's not the case.
If for any reason there is a problem with the equipment, does it seem like the lens has a problem or the camera?

EXIF Data

Camera manufacturer Canon
Camera model Canon EOS DIGITAL REBEL XTi
Exposure time 1/1250 sec (0.0008)
F-number f/3.5
Lens focal length 18 mm
Exposure Program Aperture priority
ISO speed rating 100
Shutter speed 10.2877197266
Aperture 3.61471557617
Exposure bias 0
Metering mode Partial
Flash Flash did not fire, compulsory flash suppression
Exposure mode Auto exposure
White balance Manual white balance

[oldwolf]

f/stop seems a bit low. try shooting that same picture with about f/7.0 or something along those lines and see if you get the same problem.

does this happen with your other lens?

[bardya]

I actually haven't used the other lens in a while.
I'll get back to you on that.
Thanks.

[Rob Necciai]

Also, you may want to try a couple shots without the filter. sometimes, minor defects in a filter have a way of showing up like this.

[owenmorris]

from one newbie to another I would try like f/9.0 with that kind of lens as the lower the number the more you will blur, hope it helps a little....

Owen

[Wynder]

I'd agree with some of the others -- the sweet spot for a lens with regards to sharpness is usually two full stops down from wide open. So, give it a reshoot with and without the filter and see how it comes out.