focusing with Canon 450D

[smithr99]

Exposure: 0.013 sec (1/80)
Aperture: f/14.0
Focal Length: 55 mm
Exposure: 0.00

There are 2 problems with this photo (that I think anyway). Please ignore composition and lighting etc - im trying to concentrate on a larger issue here!.

Firstly, at ISO200 I think the image is a little too grainy. I realise that Im not shooting with a 5DmkII here but I would expect better performance ?!! Please correct me if Im wrong.

Secondly, and more importantly to me, I think the focusing is off in this image (and many others like it). I took the shot a couple of weekends ago using manual focus points (focused on the "Babcock Rail" logo on the hi-vis). I tried stopping down (or is it up?!) to F14 to try and force a larger DOF and therefore hopefully bring the logo into focus. This didn't seem to have any effect and when zoomed in on the photo it still appears to be out of focus.

I guess my question is, is this my fault (camera shake, bad habits etc) or is it more of an equipment fault (possibly poor lens, faulty body etc). I have a 50mm Prime that produces much better focusing so Im thinking it may be the lens ?

Many thanks for any critique - I really want to get to the bottom of this !!

[sybren]

If it's the kit lens you're shooting with, I can imagine that it gets a little soft at the extrema of its zoom range. Try what happens at 35mm. A too small aperture (like F/16 or maybe higher) will result in softer photos as well, as the diffraction effect starts to show.

[smithr99]

it was the kit lens on this occasion yes. Im pretty sure I tried it at a variety of focal lengths and also at larger apertures but still had the same issue

[sybren]

I don't think the kit lens has a larger aperture than f/5.6 at 55mm. Please note the difference between "aperture" (the hole itself) and "aperture number" (the ratio between the focal distance and the diameter of the aperture).

You can determine whether it's a focusing issue (as you seem to suggest in the thread title) or something else, but that requires a more controlled environment. Try setting up your camera at home on a tripod. Place it in front of a table, with the lens just above the table surface. Aim it at some clearly recognisable point at the middle of the table. Now aim the central focus point on that point, auto-focus and shoot. Now you can check the photo on a computer and see whether the point is in focus, or whether the focus lies in front of or behind the point you focussed on.

If it's not a focusing issue your entire photo will be blurry/soft. If it is a focusing issue, something will be in focus.

[smithr99]

the kit lens goes from 3.5 to 5.6. Cant remember exactly where 5.6 kicks in but its around the 28mm region i think. Agreed I need to setup a test environment. That was my next step tbh. Thanks though.

Any more thoughts would be appreciated, ta

[sybren]

Yeah, that's what I thought. That means no larger aperture than f/5.6 at 55mm. Larger aperture number for sure, but not larger aperture.