another unhappy Sigma user :(

Just bought the Sigma 50mm 1.4 and when I did the focus test (http://cameralightlens​.com/newsblog/?p=264), although the middle battery seems to be in focus (sharpest out of all 5, still not very sharp imo...), the one in front is always kinda clearer (less blur) than the one behind (more blur).

Do you think it's ff and needs to be calibrated? or is it called focus shift?

Please help! The result isn't exactly ff or bf as shown on the site....so i m not sure if thats normal or it's common with this lens.

Click to see test pics -----> http://www.flickr.com/​photos/64299816@N03/?s​aved=1

Go out, Take real pictures, Report back...

well i am new to photography and I bought this lens on a gamble to replace my Canon 50mm 1.4. I heard great things about Sigma when it works, but I am just not technical enough to tell if my lens needs to be sent back for calibration thats all...

Any other suggestions?

KenjiS wrote in post #12623895
Go out, Take real pictures, Report back...

Well, Did you immediately do a focus test TRYING to find a problem or did you actually USE the lens?

Not trying to be mean, But a lot of people grab a lens and go and do focus tests, trying to FIND a problem instead of going out, using it, and seeing if they actually SEE a problem with the lens, Sometimes just shooting it a bit will tell you if somethings off...

what's wrong with trying to find the problem if the lens has one?
the focus test is a hint that the lens might have a problem. so nice job on doing that.
now you can do some real world tests too.

KenjiS wrote in post #12623958
Well, Did you immediately do a focus test TRYING to find a problem or did you actually USE the lens?

Not trying to be mean, But a lot of people grab a lens and go and do focus tests, trying to FIND a problem instead of going out, using it, and seeing if they actually SEE a problem with the lens, Sometimes just shooting it a bit will tell you if somethings off...

well based on everything i read about this lens and sigma lenses in general, I think it's fair to test the lens if it's working like it should in the first place?

I do go out and shoot with it, but since the dof is so thin @ f1.4, I sometimes can't tell whehter or not it is the lens or it's just me...

Thanks for your input pkim1230.

So based on my finding, do you think my lens is working like it should?

pkim1230 wrote in post #12623981
what's wrong with trying to find the problem if the lens has one?
the focus test is a hint that the lens might have a problem. so nice job on doing that.
now you can do some real world tests too.

Maybe post some pictures. "not very sharp in my opinion" does not really tell anybody anything. Kind of hard to give advice without seeing the photo's from your test.

Post some examples please....

im at work atm so will have to post the pic later.

Basically out of all 5 batteries, middle one is def sharpest, followed by the one directly in front, then the one behind. I have to stress the fact that the one in front seems to be always clearer than the one directly behind.

The two outmost batteries are about the same (most blurred).

So calibration needed?

GregoryF wrote in post #12624020
Maybe post some pictures. "not very sharp in my opinion" does not really tell anybody anything. Kind of hard to give advice without seeing the photo's from your test.

bring on the photo examples also the battery test only seems good for letting you know if its spot on or you should use a more precise focus test. try the ones HERE and post the results.

kin2son wrote in post #12624029
Basically out of all 5 batteries, middle one is def sharpest, followed by the one directly in front, then the one behind. I have to stress the fact that the one in front seems to be always clearer than the one directly behind.

The two outmost batteries are about the same (most blurred).

So calibration needed?

No wonder people assume all Sigma lenses are crap. Because people like you post threads with a title like "another unhappy Sigma user" even though it sounds like your lens is performing pretty much as it should.

phreeky wrote in post #12624199
No wonder people assume all Sigma lenses are crap. Because people like you post threads with a title like "another unhappy Sigma user" even though it sounds like your lens is performing pretty much as it should.

did exact same test with canon 50mm 1.4 and 85mm 1.8 and didn't have that problem. The battery directly in front and behind are more or less equal. Whereas Sigma the one in front is always clearer and very noticeable too.

So don't tell me that's normal.

kin2son wrote in post #12624257
did exact same test with canon 50mm 1.4 and 85mm 1.8 and didn't have that problem. The battery directly in front and behind are more or less equal. Whereas Sigma the one in front is always clearer and very noticeable too.

So don't tell me that's normal.

The middle one was sharp, right? How far are the batteries apart? Also difference lenses can have different characteristics of areas behind and in front of the point of focus. It sounds well within acceptable levels, and besides for all you know your existing 50 and 85 might be back-focusing a tiny bit and the body itself front-focusing a tiny bit.

If you want to be really anal, focus using liveview and then using normal AF and compare. But if you read up I think you'll find that Canon themselves consider it "in focus" at a certain print size, not at pixel level, so maybe you should be blaming Canon for how their AF system works?

Go shoot some real shots. If you find it front-focusing then look into it.

Without pictures, it's difficult for anyone to say if you need calibration or not. But, by what you're saying, it's more of a case of a lack of sharpness.

However, the level of sharpness SOOC that is acceptable (at 1.4) is down to you...and with what lenses you may be making a comparison with.

My Sigma 50 (third copy) is sharp, but not ultra sharp at 1.4, but it's at a level that is acceptable to me and responds well to a touch of high pass sharpening. It is no match for my 100 macro...obviously. Nor should yours against the 70-200 @ f4 or 85 @ 1.8.

As your copy isn't back/front focussing, I suggest you shoot people, with focus on eyes, to determine the level of sharpness of your copy. Post the pics.