How can this keep happening?

I'm using a d7000 with a sigma 70-200 apo dg macro hsm.

I can't get a sharp picture if my life depended on it.(not true, indoors at 70 mm is ok) - i can't figure out if focus is off on the camera or the lens....but i made a lot of testshots on a ruler, and they were ok.

But look at this, taken at 200 mm, focuspoint is on her face, but focus is...i don't know

200 mm, f/2.8, 1/400 shutter and iso 100

Would you say this is a lens, camera or operator issue? (dunno if i should send the lens or camera in for repairs, or work on my own limited skills)

My D7000 had to be adjusted for backfocus on ever zoom I have. Period. I thought I'd done it for all my lenses and was getting rather disgusted with the camera while on vacation last week when I was shooting some birds the first day and everything was soft (I've been spoiled with the D600 and was using that to do landscapes while the 150-500mm was on the D7000 waiting for fly-bys). I swore I'd profiled it, but when I checked it was apparent that I hadn't. I shoot mainly in the 300-500 range with it, so I went outside, stuck it on a tripod, and aimed it at the corner of a square brick post on my in-laws' house at 45 degrees and shot with minimum aperture at 400mm and sure enough. It's now set at -12 and focuses fine (all my zooms are somewhere between -10 & -18).

With your shot, you're at minimum aperture, so your DoF is perfect for revealing a backfocus issue. If you've confirmed that the focus point is on his face then it's classic backfocus since the wooden box in the right is much sharper than the boy, and the focus point may actually be somewhere closer to where the pole is on the left.

I've found that the ruler test works better under 105mm. Shooting at 200mm you'll want to do something more similar to what I did if you don't have something like this lens calibration tool. Also, know that most zooms will be soft to some extent at the extremes of focal length and aperture - and you've got both here. So even once it's calibrated your lens may not be tack sharp at these settings.

Thanks for the feedback I'll try and set up a meeting with a photographer that lives nearby, who can probably help me check it out properly.

What confuses me is that i did take some controlled pictures on a tripod, and focus was exactly where i expected it to be there, but the pictures taken out in the real world suggests that my test was wrong

first one here is 200 mm, 1/250 shutter time, f/2.8 and iso 1400...focuspoint was on the 10.

Second one is 200 mm, 1/13 shutter, f.2.80 and iso 100, focuspoint was on 35.

These suggests that focus is fine, but i don't know? single point focus and af-s

That's certainly a fair enough test to show that it's working. What was the focus mode on the original photo? It a wild guess, but I do know that in Single Point mode, if you lock in on a focus point (shutter depressed 1/2 way) and then move the camera the lock point does not move as it relates to the frame, so the subject on which the final image displays as the lock point may not be the subject on which focus was actually achieved. In other words, if the camera originally locked on the cement bench to the child's right and then the camera swung left a bit it may appear to have locked on the child but in reality did not. Again, a wild guess, but it's the only way I can explain the differences in results between the calibration shots and the original photo.

The original photo was taken in the d7000 3d-mode, i'm seeing similar results when using the 9x9 blocks focus mode.

But if not backfocus(or frontfocus) then what could be causing it...it's not like the kid was moving a lot, so she didn't move towards me, or to either side.

I'm going to blame it on 3D mode for now. I get inconsistent results with that unless I'm actually tracking a moving subject. The higher contrast of the images in the rear may be fooling the focus system. Next time try single point and see what you get.

Jake,
How can I determine what AF fine tune adjustment I should make short of trial and error. Not sure how you came up with a -12 for your 150 - 500mm lens

Cowboybillybob1 said:

Jake,
How can I determine what AF fine tune adjustment I should make short of trial and error. Not sure how you came up with a -12 for your 150 - 500mm lens

Click to expand...

Take a photo at chosen focal length and minimum aperture (for a zoom, select a most used length or max extension - my rule as zooms may vary throughout), using something that will allow you to check for front or back focus. In the Setup Menu, go into AF Fine Tune, then into the Saved Value, and then choose an arbitrary starting point (+ for front focus, - for back focus, we mathematicians choose to go binary search on you and start at +/-10 and then go half way between the gaps in successive tries), shoot another photo, compare and do it again. The camera will remember that setting for the particular lens. If you find the camera has a bent towards always going one way or another then you can set a default for all lenses (I prefer not to and just profile each one - you can save 12).

Here's a video that will walk you through it using something other than a calibration chart. Nikon D7000: Fine Tune Auto Focus - YouTube

BackdoorHippie said:

Take a photo at chosen focal length and minimum aperture (for a zoom, select a most used length or max extension - my rule as zooms may vary throughout), using something that will allow you to check for front or back focus. In the Setup Menu, go into AF Fine Tune, then into the Saved Value, and then choose an arbitrary starting point (+ for front focus, - for back focus, we mathematicians choose to go binary search on you and start at +/-10 and then go half way between the gaps in successive tries), shoot another photo, compare and do it again. The camera will remember that setting for the particular lens. If you find the camera has a bent towards always going one way or another then you can set a default for all lenses (I prefer not to and just profile each one - you can save 12).

Here's a video that will walk you through it using something other than a calibration chart. Nikon D7000: Fine Tune Auto Focus - YouTube

Click to expand...

Thank you so much Jake. It worked like a charm on my Tameron 18-270. I will have to do this for all my lenses.

Thanx great info BackdoorHippie bookmarked the video for future reference and I have a project to do today as I've been annoyed by my 35mm doing great landscapes but kids in photos are never clear unless unless closeup

I made some fast shots at different fine tune settings, and it seemed like the best results were at no adjustment, or maybe - 5 at most... Confusing stuff

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Rasmus said:

I made some fast shots at different fine tune settings, and it seemed like the best results were at no adjustment, or maybe - 5 at most... Confusing stuff

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Click to expand...

If you're getting inconsistent results then you might want to take it to a shop and have them make sure that everything is working properly. There's always the outside shot that something is amiss in your particular camera/lens.

I bought the camera online, but i suppose most photo stores can help, for a fee?


Rasmus
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If they're a Nikon dealer they should at least be able to take a look at it and see if they can replicate the problem. A good dealer will spend at least a little time with you helping diagnose whether there's a problem or not. Beyond that they would probably charge a fee for bench time, but by then you should know if it's a problem or just something you're doing.