Camera Labs

Hi

Thought you should be aware of the following. Though I have owned the Sigma 120-400mm f/4.5-5.6 OS HSM lens for my Canon 7D for a couple of months now, and have been satisfied with the results, somehow I got the impression that the pictures were kind of soft, definitively software than those taken with Canon lenses. I attributed that to the fact that this lens is not Canon and as such, its optical performance was lower than that of Canon lenses.

However, browsing for pictures on the Internet taken with this same lens, I saw pin sharp pictures that I could not get. So, to make a long story short, after reading a lot on Internet, I discovered that this brand-new lens has a front-focus problem.

I corrected this problem on the 7D by applying +15 point of compensation on the camera settings. Now the lens delivers high-quality, pin-sharp pictures, and I am pleased

So if you own this Sigma lens for a Canon body, check it for front-focusing problems.

Regards,
Luis.

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Canon 5D Mark II
Canon 24-105mm f/4.0 L

Everybody should check a new lens for front-/backfocus.
Even my brand-spanking new Nikon 70-200 VRII needed micro-focus adjustment of around +6..+8 (out of 20 max)

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

You bought a Sigma lens, and expected it not to have this issue? Or at the very least, not to have to check for it?

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I've upped my Iso, now up yours.
Nikon D700, Nikon D80, Micro Nikkor 105 f2.8 AI-S,Nikon 85mm 1.8D, Nikon 50mm 1.8D, Nikon 35mm F2D, Nikon 16-35 f4 VR, Nikon 24-70mm F2.8 AF-S, Nikon 70-200VRII, Nikon 70-300mm VR, 300mm f2.8 AI IF ED, SB-800, SB-900. Noiseware pro,NIK Dfine, Nik Colour Effex, Nik Sharpener Pro

You are correct Gregory, I bought a brand-new Sigma telephoto lens, and did not expect to have this issue.

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Canon 5D Mark II
Canon 24-105mm f/4.0 L

You know Gregory, we all don't think of everything when we buy new lenses. I had my 50D for about a month before I realized that I could adjust the front/back focus on lenses.

You came across a little condescending there.

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Canon 5D Mk II * 17-40 F/4L * 24-105 F/4L * EF 70-200mm f/4L IS * Tamron 28-75 f/2.8 * EF 50 f/1.4 * Lensbaby Composer * EF 100-400 L * EF 100 F/2.8 Macro * EF 1.4x Extender III * Speedlite 430EX II * Speedlight MR-14EX *

I believe mine has the front focus issue. For some unknown reason my 50-250mm lens is razor sharp open wide while this lens at at 300m F6.3 is soft. It's going back today

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Canon T2i (550D)- Tamron 17-50 F2.8 Non-VC, Sigma 70-200mm F2.8 EX DG OS HSM, Canon EF-S 55-250mm F4.5-F5.6
http://www.astronomyphotography.com

Is this something I could do on my little Canon Rebel XS and if so - how do you do it ? Sorry for my lack of knowledge here.

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Larry
"Have you hugged your pet today"
-Canon EOS Rebel XS
-EF 28-135 f/3.5-5.6 IS USM
-EF 70-200 F/4 L (non IS) USM
-Canon EF-S Macro USM 60mm USM

i believe that focus adjustment is only available in the 50D and upward models..

i probably should check my 70-200 F2.8 once but ill wait till i get a camera that can do adjustment

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DeviantArt
Canon 1D MK3, 1x580EXII, 1x430EX
Canon 50mm 1.4 USM, Canon 100mm F2.8 USM
Canon 70-200 F2.8 L IS II, Canon 16-35 F2.8 L
Sigma 300mm F2.8

Canon Pixma PRO-9000 MKII

and a 17-40 F4L in a hundred little pieces