Issue with new Sigma 10-20mm

My brand new Sigma 10-20mm 4.0-5.6 came in the mail yesterday and i was really excited. I snapped some quik pics inside and noticed the lens was really sharp in the center but the edges on both sides seemed fairly out of focus. I didnt want to judge it on pics in poor light inside so i decided to test it out today outside. Looks like its exactly the same. I took pics at different apertures because i know this lens is sharpest at f8-11.

Please take a look at these and let me know if i need to send this in to sigma, Ny. I dont see any difference at 4.0, 8.0 or 11.

center focus point used on all pictures and they are jpegs straight out of the camera. Am i imagining things or is there something wrong.

10mm f/4.0

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Wow, I really see what you are talking about, if it were me, I would send the lens back, but I don't have enough experience to know what else to do. I am sure others will chime in.. but I can defintely see how the sides/edges of the photos are not in focus and are soft.

Honestly, it is hard to tell. All lenses lose resolution at the edge, especially UWA lenses like this one. According to photozone.de review, this lens should be 15% less sharp at the edge at f/8.0. Does it look more than 15% less sharp on your shots? Probably. If you think you are not happy with this performance, you can always send it to Sigma.

i understand it being less sharp i knew that when i decided on the sigma over the canon. Its just fairly blurry. Pictures of objects its really noticable.

im pretty new to photography and this is my 1st aftermarket lens. i just wanted people to confirm what i was seeing before i decided to send it in to Sigma.

Do you have a filter on the lens? If so, retry without it.

As pulsar123 noted, it's not uncommon for lenses.... particularly ultra wides... to be a little soft in the corners wide open. Some have optical vignetting (a darkening of the corners) too. But these things really should improve when you stop down to f5.6 or f8. You also might want to make some test shots at other focal lengths, also at several apertures, to see if they're any better.

I looked at the Sigma 10-20 way back some years ago when I was shopping for an UWA. I wasn't impressed with it and ended up buying the Tokina 12-24/4 instead. However, I think the Sigma has been revised since then, so yours is probably a different version that I haven't tried.

You also might search the Lens Image Photo Archive subforum attached to this one, to see what other people are experiencing with the same lens... That might tell you if this is typical or if yours is a "bad copy".

Mine had the same problem but after sending it in for calibration it's so much better, light and day.

Send it in they will sort it.

No filter on the lens.

I did search the image archive and i really thought i had a bad copy but i didnt know if i was being overly critical. Going to contact them and see what the deal is with sending it for calibration.

maybe I'm old with bad eyes, but it looks normal for a UWA......

How about this one? I know the pics are not great but im at work and dont have good subjects to take pics of.
the door on the right side is clearly blurry and the bricks on the left off center start to blur.

10mm f/4.0

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Still looks pretty bad.. I would send it in for calibration or just return it all together, if it were my lens i would be very unhappy with it..

it's more telling on the vertical lines on the roof than the bricks....left side really blurs..send it back..you won't be happy with it as is

Return it. I have that lens and it is excellent. It is not 17-55 IS sharp but really good. The borders are a little softer than the center on mine but you need to look at 100% to see any difference. I would give the sigma another shot though. It is one of my favorite lenses.

At those resolutions its hard to say. The images at f9 and above seem perfectly fine to me. The wall image may be making it seem worse than it actually is because your focal plane is not parallel to the wall, you are at an angle. The one at f4 with the trees does seem a tad soft at the edges, but again, can't really tell because of the image size.

If you aren't sure about it, send it in under warranty for them to have a look at it.

im taking it back to the store tomorrow. We are going to look at it there and try some other lenses copys in the store to find a better one.

for those of you who cant tell with the size, click on the pic and it takes you to my flickr and the original size is on there.

i couldn't tell until you posted the wall shot...it looks like the left side is considerably worse than the right...it might have a decentered element which does happen with this lens...take it back, and get a good one