120-400 OS Sigma &7D

[GaryJ]

Before I knew better I bought the 120-400 OS following advice from one of the magazines,this lens has never worked properly giving milky pics with ghostlike halos around subjects,an allover softness which I liken to a Doris Day filter,funnily enough it turns out quite sharp and clear portraits on my friend's 5DmkIII.Has anyone come across a fix to get this lens to work on the 7D,have tried the AF adjust to get the focus to work,still has milky images.It turns out slightly more acceptable images on my 450D but still with a Doris Day filter

 

[Hesbehindyou]

Two really obvious things here:
1. Is it better with manual focus/liveview with contrast detection?
2. We need pictures. Would you post some?

 

[pwp]

Hmmm sounds decidedly odd. Do your other lenses work OK on your 7D?

The Sigma 120-400 is never going to be a match for good L glass such as the most obvious equivalent, the Canon 100-400L. But the Sigma is half the price. Even so, what you describe absolutely shouldn't be happening. If you bought it new I'd be looking at a refund or a fresh copy if you're still inside the 14 day DOA period.

-PW

 

[alexturton]

I have the sigma120400 OS with 7d.

Mine front focusses by about 10 (which gives the soft look you described). After calibration is a lot better, but still slightly soft @ 5.6 but still very usable for up to A4 prints.

THis was at 5.6 http://www.flickr.com/photos/alexturton/7475200930/#


Gets very sharp at 7.1

Other samples: http://www.flickr.com/search/?w=58384486@N07&q=120400

The canon 100 400 is sharper @ 5.6. Both about the same by f8.

Because of the small max aperture I generally only use my sigma in good light.

 

[GaryJ]

Two really obvious things here:
1. Is it better with manual focus/liveview with contrast detection?
2. We need pictures. Would you post some?

find it hard to use live view with birds,am viewfinder shooter except macro,will post shots from 5DmkIII,450D and 7D,will search them out and post.Thanks

 

[GaryJ]

I have the sigma120400 OS with 7d.

Mine front focusses by about 10 (which gives the soft look you described). After calibration is a lot better, but still slightly soft @ 5.6 but still very usable for up to A4 prints.

THis was at 5.6 http://www.flickr.com/photos/alexturton/7475200930/#


Gets very sharp at 7.1

Other samples: http://www.flickr.com/search/?w=58384486@N07&q=120400

The canon 100 400 is sharper @ 5.6. Both about the same by f8.

Because of the small max aperture I generally only use my sigma in good light.

similar front focus issues,have 70-300L which is a delight to use and extremely sharp will happily swap my Siggy for yours,lovely shots.

 

[GaryJ]

Hmmm sounds decidedly odd. Do your other lenses work OK on your 7D?

The Sigma 120-400 is never going to be a match for good L glass such as the most obvious equivalent, the Canon 100-400L. But the Sigma is half the price. Even so, what you describe absolutely shouldn't be happening. If you bought it new I'd be looking at a refund or a fresh copy if you're still inside the 14 day DOA period.

-PW

way outside return period,grey import[AUS],all other lenses,bar Sigma 150 F2.8 macro: 100 f2.8L IS,70-300 L IS,70-200 f4 L and Tokina 11-16 are sharp and crisp,the Siggy 150 is fine in manual and sometimes AF,doesn't display same degree of Doris,shall post so as to give you fine folks an idea of prob