Sigma 10-20mm F4-5.6 DC HSM driving me mad

Hi Guys, New member here and a bit of a newbie in the mad world of photography as well.

I have a 650D and this 2 month old Sigma 10-20mm F4-5.6 DC HSM is driving me a bit crazy. I concede that i was a little paranoid about getting a "bad" copy even before i purchased one. Maybe it's that or a valid reason but i do not feel completely satisfied with the results i am getting with it. I have put up a few sample images on Flickr.

http://www.flickr.com …5/sets/72157640​117729855/

All photos were handheld. The Exif data is included in the links.

Admittedly i was initially using the widest apertures (beach pictures) and later switched to narrower apertures(Cricket match)
I hope someone who's used this lens extensively could look at the images and advise me regarding the IQ. I even took it to the shop i bought it from because i was concerned about the general "softness" of the images. They took a couple of shots of a close object and said it was fine after looking at the LCD

I am essentially trying to determine if this lens needs to go back to Sigma for calibration or not. Please help! Thanks.

EDIT: Some further testing based on advice received in this thread. A tripod was also used. Please see link below

http://www.flickr.com …5/sets/72157640​314315856/

Do you have a filter on it ?

David

Where are you focusing with your AF point?

like in the foreground, middle or background?

The in focus parts looks really good and sharp.

^^^^ Ahhh that may be it a ultra wide has so much in view it's important to focus on what you want to highlight in that scene , guess that's why they say with a UW "Get close" .

David

Xscaper wrote in post #16633358
Hi Guys, New member here and a bit of a newbie in the mad world of photography as well.

I have a 650D and this 2 month old Sigma 10-20mm F4-5.6 DC HSM is driving me a bit crazy. I concede that i was a little paranoid about getting a "bad" copy even before i purchased one. Maybe it's that or a valid reason but i do not feel completely satisfied with the results i am getting with it. I have put up a few sample images on Flickr.

http://www.flickr.com …5/sets/72157640​117729855/

All photos were handheld. The Exif data is included in the links.

Admittedly i was initially using the widest apertures (beach pictures) and later switched to narrower apertures(Cricket match)
I hope someone who's used this lens extensively could look at the images and advise me regarding the IQ. I even took it to the shop i bought it from because i was concerned about the general "softness" of the images. They took a couple of shots of a close object and said it was fine after looking at the LCD

I am essentially trying to determine if this lens needs to go back to Sigma for calibration or not. Please help! Thanks.

Heya,

Wide open, it's not going to be as sharp as when stopped down. Focus to infinity. I'm not sure how you achieved focus, but overall, it looks fine to me, but looks a touch soft around the edges (normal) with distortion, and the center areas look the sharpest. If you did not, I would recommend you focus to infinity manually. Do not use autofocus unless you're trying to focus on something in the foreground specifically. For landscape, big scenes, etc, you want to stop down to F8 or F11, manually focus to infinity, and you're good to go.

Looking at all your images, the beach ones, the trees are soft. But other things are sharp. This tells me it's not the lens, but rather, your focusing and the fact that it's wide open aperture, not stopped down.

Looking at the stadium, the center stuff is sharp (antennae, edges of building, etc), but the peripheral stuff is softer. That's probably the lens a bit and that's due to distortion and all, maybe. I'm not positive on this one.

Did you use autofocus, or did you manually focus to infinity? I would suggest you use LiveView, magnification 10x, and manually focus on something distant (tree line, building edge) for sharpness. Call that infinity for your shots. And leave it set to manual so autofocus doesn't change it. If it's still soft, pitch the lens, get something sharper (10-22mm Canon, 14mm Rokinon/Samyang, 11-16mm Tokina, etc).

Very best,

For hand-held UW shots, I don't see anything wrong with the photos

A little soft I think...

Click on this image and then two times at the magnifying glass at the bottom right of the successive images. You'll get a full res photo at 16 mm to compare.

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MakisM1 wrote in post #16633611
Keep in mind though, you will never print or show the full res.

I remember when I first got my ultrawide, I instantly thought it was soft when I viewed it at 100% on a monitor. Pooped a little bit at the thought of it being that soft and instantly started getting ready to return it.

Big learning curve going to ultrawide and understanding the sharpness for the perspective or potential format it will be viewed. Good point about the show/print in regards to resolution. Hard lesson to learn for some (myself included).

IMAGE LINK: http://www.flickr.com/​photos/mwise1023/12093​995785/

I had issues with mine with the Left Hand Side being soft. It didn't always show up in my images though and I doubted myself for a while. I took a few pics tripod mounted of my brick house. Zoomed in showed the differences between LHS and RHS. I took it back and had a replacement lens which is fine..........

Don't see anything concerning, practice more and stop stressing. The way people carry on on the web sometimes you would think every other Sigma lens is soft, they aren't.

Looks normal. The 10-20 lens is good, but c'mon, there is a reason it is what it is.

I struggled with mine at first, really, you want to shoot f8-12 if you can and either focus on subject, or hyper focal or focus first 3rd or whatever. Once you get used to it, it is a good lens.

Here you go, When I first got it I had some pics like yours, if you click on this set, I am pretty sure every picture in this set was taken with that lens, and MOST all with a rebel Xsi

http://www.flickr.com …r/sets/72157630​521901650/

it looks a littlesoft to me...but i do wonder if you have a filter on it as well...especially with the double flare in the first cricket shots...also stopping it down to about f8 should be the sweet spot

you do want to make sure you know where you are focusing, i typically focus about 4 feet in front of me, and with the large DOF everything else is in focus as well...if you point it to the other side of the stadium you're not going to get the best shot sometimes, or if you are shooting at f4, and aim too close you won't have the DOF extend all the way to infinity

i do agree with others that you don't want to over-analyze at 100%

It does take some practice to get used to the UWA, as with any lens. Out of my lenses, I think I've printed more photos and dramatic scenes from my 10-20mm than any other of my lenses; its a great lens.

I noticed on a few of your shots you were shooting wide open, but also at like 1/4000s shutter and iso1600. You could probably stop it down some and drop your iso, while keep plenty decent shutter speeds. The nice thing about an UWA is that you dont need a very high shutter to keep things sharp. You were missing exif info on flickr for quite a few, but I'd recommend stopping down, dropping the iso and not using such a fast shutter.

dpds68 wrote in post #16633412
Do you have a filter on it ?

David

Yes, a UV Filter which wasn't there for the beach shots but present for the cricket.