Lens issues

12sndsgood · Apr 7, 2012

I recently picked up a Sigma 24-70mm F/2.8 and although I have not shot allot thru it, i'm having allot of blurryness issues. I'm sure some of it is do to me, but it just seems way to many shots are coming up with issues then would account for user error. I also picked up a tamron 70-200mm F/2.8 and I'm not having issue with it. Even shooting yesterday I seem to have blurryness and what looks like haloing around some things. it's the weekend so kid and family stuff going on but I will be trying to do a more confined test on the lens monday morning to see if I can truly find out what the issue is. I remember a post a week or two ago about someone having issue with his lens and having to send it back for re-calibration and i'm starting to wonder if this may be the same type issue.

As I said, Monday i'm going to setup a test, but heres a few photos I have gotten, I Just think if it's all user error that I would have allot more problems getting clean shots with the 70-200 versus the 24-70.

Nolan 0614 by Square1 photography, on Flickr

polarbear0002 by Square1 photography, on Flickr

Nolan 0587 by Square1 photography, on Flickr

tirediron · Apr 7, 2012

It certainly could be a back/front focus issue, and without the EXIF data, it's hard to guess. Try this test. Set up a row of objects starting about ten feet from the camera lens with an object (book, traffic cone, whatever so that they're all the same size and colour), mount the camera on a tripod and set it to manual. Using auto-focus focus on the centre object in the line, and shoot it wide open; check focus. If it's good, then you're fine and you can assume user error. If it's not good, repeat the test focusing manually. If that's good, you likely have a minor auto-focus alignment issue. If that's not good then you probably have a more serious issue.

KmH · Apr 7, 2012

Sigma AF 24-70mm f/2.8 EX DG HSM (DX) - Review / Test Report - Sample Images & Verdict

The only real issue of the lens is it's unpleasing bokeh. If your intended primary usage is to shoot portraits or seperate the main subject from a blurred and smooth background, you should probably look elsewhere.

The 2 photos of the boy were made in really poor light, and from to far away.

12sndsgood · Apr 7, 2012

I'll try that Monday tired.

Kmh. I was only around 10 feet away give or take on the one of him on the table how would the light effect the clarity of the photo?

480sparky · Apr 7, 2012

Bring the image up in ViewNX.... it's the software that came with the camera. You can view the focus points used by the camera to see where it was looking at to focus.

cgipson1 · Apr 7, 2012

#1 64mm, F5,3, ISO 200, 1/500 (per Flickr Metadata)
#3... 70mm, F3.5, ISO 200, 1/500, manual mode

at those settings, at 10 ft.. you do have less than .82' for DOF. If you were off just a bit, that could cause the issues you are concerned about.

was the bear shot with the same lens? (F5, ISO 100, 1/1000) if so.. what was the distance on that...

12sndsgood · Apr 7, 2012

Correct, I should have had little less then a foot of focus. 4-5" in front and back roughly. The focus point according to view nx was on his right eye, maybe a inch or two to the left of the right eye to be exact. At that point some point of his face should be in focus. but I can't find any point on his face or anywhere else that appears to be in focus at all. I used a single point focus point.

The bear was a bit farther away, guestimating I would say around the 25' range. Which i'm thining should have given me a few feet in either direction.

And I havn't ruled out user error. It just seems most of these with this lens are blurry. where I could switch to one of my other lenses and not have the problem at all. I would think if it was user error it would happen with any other lens I use. But monday it will definatly get some testing done.

here is another one. and even though it was shot at 2.8 According to view nx my focus was on the tulip on the right in the center. dead center. and nothing appears to be in focus at all.

test0003 by Square1 photography, on Flickr

KmH · Apr 7, 2012

12sndsgood said:
Kmh. I was only around 10 feet away give or take on the one of him on the table how would the light effect the clarity of the photo?

The actual focus points in the viewfinder are quite a bit smaller than the [ ] that indicate where they are. The actual focus point may not even be in the center of the [ ]. Cross type points have a horizontal and a vertical detector, like +. The non cross-type points are either horizontal, and detect vertical edges, or are vertical points that detect horizontal edges.

If you focused on his face, the hard shadow diminishes the contrast, which is what the auto focus system uses to judge focus. Specifically, the AF system uses edge contrast to judge focus.

12sndsgood · Apr 7, 2012

Okay, first off forgive my first grade drawing below. was just doing this quickly. the blue box is where the focus point was according to view nx. now the red lines are the dividing lines between the bright and shaded areas. So is what your saying is that since the majority of his face was in shadow there wasn't enough contrast in his face to get a good focus and caused the camera to think it was in focus when it really wasn't or am I not thinking that thru properly. and if that is the case what would be your best option of focusing in this type of situation (even knowing it was a horrible lighting situation) Seems so many people say that full shade is great lighting. if the majority of his face was in the shade wouldn't that be a good focusing situation? Thinking I need to pull out the manual tomorrow on the D7000 and re-read the focus points. I had thought with the single type focus that I was using a single focus point which I assumed would be centered in the bracket.

test2 by Square1 photography, on Flickr

cgipson1 · Apr 7, 2012

They do call it the "Sigma Lottery" with reason.. you may have gotten a bad copy.

cgipson1 · Apr 7, 2012

12sndsgood said:
here is another one. and even though it was shot at 2.8 According to view nx my focus was on the tulip on the right in the center. dead center. and nothing appears to be in focus at all.

test0003 by Square1 photography, on Flickr

Actually the tulip in the left center is relatively sharp.. I can see some detail at least! Much more so than the one you focused on... looks like it may be back focusing..... hmmmmm!

12sndsgood · Apr 7, 2012

I noticed that as well. and from remembering the tulip layout they seemed to be at least a few feet apart so that one you mentioned is likely a foot or two behind what I was actually focusing on. and even though it is still out of focus, it's definatly more clear then the others.

And I probalby should have waited till after i did a proper test to ask this question. But it's just one of those things that once it gets in my head it digs and me and digs at me until I find the solution. Just looked at my recipt and I should probalby get on this. my 30 day return date looks to be monday. I think I will be testing tomorrow.

lonewolfsx · Apr 7, 2012

Hmm yeah it looks like a focusing issue to me, because that one sharp-ish tulip on the left side of the frame looks pretty good (though dark). Does the D7000 have focus microadjustment? I can't remember but you could try to adjust it with that. If it doesn't have enough range to adjust then this may be something you have to send in.

Also, which Sigma 24-70 is this? the Macro or the HSM version? I ask because I'm very seriously considering picking up the Macro version, but it's only available used so focus issues like this can be problematic as opposed to new lenses where you can return them..

12sndsgood · Apr 7, 2012

This is the HSM model. Just my luck as well B&H is closed until april 27th for passover. So even if it is the lens issue i'll likely won't be able to rectify the issue for 5 or so weeks. yay me lol.

I will have to see if there is a focus micro adjust. but I would think if that were the case i'd be having similar issues with other lenses.

cgipson1 · Apr 7, 2012

12sndsgood said:
This is the HSM model. Just my luck as well B&H is closed until april 27th for passover. So even if it is the lens issue i'll likely won't be able to rectify the issue for 5 or so weeks. yay me lol.

I will have to see if there is a focus micro adjust. but I would think if that were the case i'd be having similar issues with other lenses.

There is an adjustment on the D7000.. but as to whether it will cover that much adjustment, I doubt it! I had to tweak my Sigma 50mm 1.4 about 4 points.. and it was only a couple of inches off.