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I'm really into landscape photography but I can't get my pictures to look sharp. They look boring and dull. I focused to infinity by using the infinity symbol on my lens and by manually focusing using an app which calculates the DOF. According to the app if I set my aperture to f/5.6 and zoom all the way out to 10mm, I should have a DOF of infinity when focusing on something that is 3m away. I tried different apertures but the higher I go the blurrier it gets. Is the lens just not good? I saw some reviews and they weren't as good as I was hoping. They all found that the lens is not sharp and when looking at example pictures on Google that were taken with the same lens, they all look unsharp. Should I get a different lens or am I doing something wrong?

EDIT: Before I asked this question, I already did all the things mentioned in the question, http://photo.stackexchange.com/questions/50006/why-are-my-photos-not-crisp

I tried manually focusing at the furthest subject to really make sure it's within infinity and it's still not sharp. Even if I take a picture of a subject that is just a few cm away, and focus so that it looks crisp in the display, it doesn't turn out crisp on the computer. I can see a difference between f/5.6 and f/3.5 in sharpness but if that is the best I can get out of that lens I'll be very disappointed.

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Here is one picture I took of the field next to our house. I took it when I got home. I increased the exposure a little with camera raw. It looked really bright on the camera display but on the computer it was underexposed. I focused to infinity and put it on a tripod and set up auto shutter release. This is the terrible outcome:

ISO100, 0.5s, Sigma 10-12 f/3.5 @16mm f/5.6

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For example, this picture here was taken with the kit lens before I started getting into photography, meaning before I knew anything about aperture, DOF, etc. and it's really sharp compared to the 'better' new lens. So I must be doing something wrong with the new lens because the old picture shows that I'm able of taken sharper pictures. Generally, all I the pictures I took with the kit lens are way sharper.

https://i.imgsafe.org/ba4b11b740.jpg

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  • \$\begingroup\$ Chris, the link to your image taken with the kit lens is dead. Normally, I'd ask if you could find a copy of it and upload it to your question. However, it seems the point of that image was to prove you could take sharp images. I don't think that's necessary. Perhaps just remove references to the last photo, as a suggestion? \$\endgroup\$
    – scottbb ♦
    Mar 9, 2018 at 21:18
  • \$\begingroup\$ Have you tried using liveview with magnification and manual focus, rather than zone focusing by the distance scale? \$\endgroup\$
    – inkista
    Mar 10, 2018 at 3:53

3 Answers 3

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The Sigma 10-20 f/3.5 EX DC) has issues with lens quality specifically "sharpness degrading" and auto focus.

First, compare between manual focus and auto focus. Consider using a shutter release. Did the sharpness improve?

There may be an issue with the lens and may need to be sent back to Sigma for adjustment/calibration/correction.

From the Sigma 10-20mm f/3.5 EX DC HSM Lens Review: "With a wide open aperture, the Sigma 10-20mm f/3.5 EX DC HSM Lens is sharp in the center with sharpness degrading to somewhat soft in the frame corners. At f/5.6, the corners improve a noticeable amount - to very nicely sharp. I don't think that you will notice the improvement realized by stopping down beyond f/5.6."

"...the fixed maximum aperture allows a constant wide open aperture exposure setting to be maintained over the full focal length range of the lens... Unless you are using manual focus, focus accuracy is very important to final image quality"

Taking a step back... the lens is trying to capture the widest view angle and flatten it. The lens is also compensating for the small sensor and further manipulating the image. It's essentially making a orthographic projection and cramming it into a rectangle.

Update: Have you isolated the issue to lens or the camera? I recommend borrowing or testing a premium lens to make sure it is not a camera issue as well. Likewise for the camera. I know the Ti3 is much better than the Ti2 and that may be compounding the issue.

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  • \$\begingroup\$ I read that review as well. I'm using the shutter timer (2sec) and it improved a little but not to the point where I could compare it to a professionally shot picture. It just looks like whatever. I have to fiddle around in post to make it look crisp but that gives me a lot of noise. I'll post some example pictures as soon as I get home. \$\endgroup\$
    – Chris
    Dec 20, 2016 at 20:53
  • \$\begingroup\$ @Chris Pretty much ALL of those "professionally shot pictures" have a lot of post-processing in them as well. Having said that, in general for wide-angle APS-C lenses the Tokina lenses get better reviews than the Sigmas. \$\endgroup\$
    – Michael C
    Dec 22, 2016 at 6:00
  • \$\begingroup\$ Thanks for putting up the other shots. It leads me to conclude the Sigma lens is less than excellent, still a good lens, just not excellent. I believe the lens may perform better on a newer camera. If you want excellence guaranteed in lenses go with Canon and stick with L glass - the lens has to have an L at the end. \$\endgroup\$
    – Jeff in Palm Beach
    Dec 22, 2016 at 14:17
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Based on the sample image(s) and the described process you are following it does appear as though there is an issue with your lens. To be certain, you could try the same lens on another camera body. At this point I would consider sending it back to Sigma for calibration.

To be clear - I am not in the same boat as some others (and apparently you) that this lens in general is so under-performing that one should expect results like this. It looks like a fine lens to me.

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    \$\begingroup\$ I also don't think that the lens performs so terribly. I will go back to the store today and ask them to test the lens with a few different bodies and if they come out just as unsharp I'll either exchange it or get it calibrated. \$\endgroup\$
    – Chris
    Dec 22, 2016 at 23:37
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I think you've misunderstood what "focused to infinity" means: in particular, it doesn't mean that everything closer than infinity (i.e., everything) will be in focus.

Focusing at a particular distance means that everything close to that distance will be in focus. The exact meaning of "close to" will depend a variety of factors but, if you keep the focal length fixed and keep the lens on the same camera, then it just depends on the aperture you use. Wide apertures (small F-numbers) mean something has to be pretty close to the focal distance to be in focus; narrow apertures (large F-numbers) mean it can be quite far from the focal distance and still be pretty sharp.

So, you've focused at infinity and you're expecting objects that are pretty close to you (i.e., very far from infinity) to be in sharp focus – the foreground of your example photo looks like it's only a short distance from your feet. If you want the foreground to be sharp, you need to be focusing closer than infinity. Because we're talking about a very short focal length, here, the depth of field (distance between the closest and farthest points in acceptable focus) will be very large so you probably won't need to focus much closer than infinity. If your camera has live-view, use that to see if you can get something really sharp.

The bottom line is the foreground probably won't be in focus if you focus at infinity.

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