Help with wide angle Lens

[allanbeth]

Hi Guys,

Hope this is the correct place to post this.

I recently bought a new body of a family friend with it came a few lenses.
A Canon 17 - 85 IS & a Sigma 12 - 24 DG HSM wide angle. Whilst the canon lens is great for me and i have been using it alot, i went to try out the sigma. My issue is this. all the images are coming out a bit blurry. really un-sharp. is this the lens? having seen some other peoples images with this lens i am at a loss a to what i'm doing wrong.

I am using an Eos 40D. please help

[RichardTaylor]

Could you please post an example along with exif data?

[allanbeth]

Picasa Web Albums - Quanta Photography - Online

f16
1/50 sec
21mm
Eos 40d

Couldn't get it to embed so have to use the link

Thanks

Allan

[RichardTaylor]

It doesn't look real sharp to me either (looking at the original)

Was there a filter on the lens?
If there was try removing it & see what happens.
Where exactly did you focus?

I would try a couple of test shots, say of a brick wall, with the camera on a tripod or at high =>1/200 shutter speed so camera shake can be eliminated as a problem.

[allanbeth]

no filter on the lens, The above image was set to auto focus.

I'll do some test shots like you suggested.

Thanks

[allanbeth]

Done some test shots

Picasa Web Albums - Quanta Photography - Online

it's like the lens wont focus properly.auto or manual. Do lenses get uncalibrated?

[allanbeth]

Just got back from the local camera shop, They told me that there is nothing wrong with the lens. it's an old lens designed for film cameras, as my camera isn't full frame this is what is makingthe images so soft. they suggested that i should use at higher f/stop.

Does this sound right?

[OsmosisStudios]

Originally Posted by allanbeth

Just got back from the local camera shop, They told me that there is nothing wrong with the lens. it's an old lens designed for film cameras, as my camera isn't full frame this is what is makingthe images so soft. they suggested that i should use at higher f/stop.

Does this sound right?

No, it's patently false.

The lens is soft: I'd suggest sending it to Sigma for a repair. That's unnecessarilly soft. You want help yourself, though, by shooting with a larger aperture (around f/8 or f/11, at most), which will also help raise your shutter speed.

[inkista]

Try three things, first, with a test shot.

1) put the camera on a tripod so that shutter speed/handholding technique won't be an issue.

2) manually focus with liveview and 10x magnification, to take autofocus and manual focusing errors out of the equation.

3) set the aperture to f/8.

If the shot is still fuzzy, then there's probably a problem with the lens. If it's sharp, then the issue may just be autofocus calibration. Yes, lenses do get uncalibrated over time.