Sigma 30mm f1.4 EX DC HSM

me too

Also love mine. And to think I almost let the "bad copy" stories get to me, glad I didn't get a Canon 28mm f/1.8 instead.

Shot at f/2.5

View on black

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

Hi, I´ve recently received my 30 mm, did some test and everything about af is ok; no front or back-focus problems, just one thing: I suspect there is some decentering problem -not very pronounced though- as the extreme right side (note, not just the corners) is out of focus, more visible than the left side, from 1.4 to f/8. It´s the only little dissapointing issue, so I´m thinking about sending it for a calibration instead of trying a new copy.
So, Is there anybody who had a similar problem of decentering with a happy ending after a trip to sigma´s technical support?

thanks and regards...

Are you sure that isn't your body doing the decentering ? Had it on my 400D. On my 50D it isn't quite as apparent.

what do you mean?
I have not seen such decentering effect on the rest of my gear (35 mm f/2 17-40L, 28-135 nor the "ef-s" such as 18-55...just a little on my sigma 10-20.

regards

the body is 40d. The only one that i have...by now

I just got mine today. I think mine is one of the bad mis-focusing ones . Check out these focus test shots:

HOSTED PHOTO
please log in to view hosted photos in full size.

HOSTED PHOTO
please log in to view hosted photos in full size.

test charts are not the best way to see if a lens is misbehaving - they can often focus on somewhere quite different to where you think they are focusing... most of the siggy 30's front/back-focusing faults show up better at longer range

try placing a subject about 8 feet away beside a fence or wall that comes towards you, and focus on the face at f/1.4, then see if the shot is sharp; and if not, where does the wall come into focus... behind the subject or in front, and how far?

cracotzia wrote in post #8128205
what do you mean?
I have not seen such decentering effect on the rest of my gear (35 mm f/2 17-40L, 28-135 nor the "ef-s" such as 18-55...just a little on my sigma 10-20.

regards

Neither have I seen it on my other gear. Yet getting another body 'solved' it. You probably won't notice quite as easily with other lenses, because their DoF isn't as ridiculously shallow as the 30mm.


@secretpact - that doesn't look too bad just yet. I'd give it some shots for real and then make up your mind.


Edit: btw, secretpact's test chart shots seem to show a bit of decentering as well. Unless I'm very mistaken about what was meant by this in the first place

X-Warrior wrote in post #8133378
Edit: btw, secretpact's test chart shots seem to show a bit of decentering as well. Unless I'm very mistaken about what was meant by this in the first place

I don't really know what you mean by decentering, but my images were cropped hastily. lol sorry.

X-Warrior wrote in post #8133378
Neither have I seen it on my other gear. Yet getting another body 'solved' it. You probably won't notice quite as easily with other lenses, because their DoF isn't as ridiculously shallow as the 30mm.

@secretpact - that doesn't look too bad just yet. I'd give it some shots for real and then make up your mind.


Edit: btw, secretpact's test chart shots seem to show a bit of decentering as well. Unless I'm very mistaken about what was meant by this in the first place

shallow DoF? possible, but not at f/5.6 with a subject 50 m. away, and at that value the problem exists. I Compare it for example to canon 35 f/2 using the same aperture value (5.6) and the canon (being of course EF-"sweet spot on aps") doesn´t show any problem of that kind.

Still don´t know if any kind of calibration by sigma service should be possible and satisfying or maybe I should send it back for a refund...

thanx for the comments...

nik.hisham wrote in post #8137534

HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR

What is this picture of? It is so vibrant! I love it.

secretpact wrote in post #8134119
I don't really know what you mean by decentering, but my images were cropped hastily. lol sorry.

What I mean is the sharp area going a bit from the top-left to the lower-right, instead of straight from left to right.
I assumed this was what cracotzia meant by 'decentering'. If not, just ignore all I said before