Wide angle focus problem

ImageX Photography · May 4, 2011

I was hoping someone can help me diagnose a possible lens problem. I have a Tamron 17-50 VC that is having trouble focusing at the wide end at infinity. It will just not find focus on distant subjects at all. If I zoom in just a little... to maybe 25mm or so... it will lock on. I played around with the D300S fine tune and when I set it to -15 or so, it will lock. Has anyone ever experienced an issue like this before with their wide angle lens? Does the lens just need calibrated? If my subject is closer, it will lock on fine. It seems like it needs just a tad more focus past infinity to lock on but it's all the way out. I'm guessing it needs calibrated by the factory? Could this be a camera issue... because my Tokina seems to be having a little trouble too. I did drop my camera a few weeks ago but I'm not sure if that's it. It's only at the the very wide end. :scratch

Pupator · May 4, 2011

So did setting the micro-focus adjustment fix it? Or is the camera now back-focused when it locks?

newb · May 4, 2011

I have a different camera and lenses, but Ive never had trouble with a wide angle not finding focus at the wide end and infinity. Just easier to miss the focus on distant subjects.

ImageX Photography · May 4, 2011

Pupator wrote: »

So did setting the micro-focus adjustment fix it? Or is the camera now back-focused when it locks?

I'm not sure if it's backfocus.....but not in focus either way. I only played around with it a little bit and then ran out of daylight. I'm confused why the camera would start grabbing focus at -15 to -20 even when it's not focus.

ImageX Photography · May 4, 2011

newb wrote: »

I have a different camera and lenses, but Ive never had trouble with a wide angle not finding focus at the wide end and infinity. Just easier to miss the focus on distant subjects.

Yeah, it's generally tougher to find focus on such distant subjects with a wide angle but I didn't have much problem before. It's only on the extreme wide end. If I zoom in just a few MM's, it will be fine with no problem.

newb · May 4, 2011

Right, but whats weird is that it wont lock the focus. Ive never had that problem. Even if I miss the intended focus with my 17-55, itll still lock.

ziggy53 · May 4, 2011

If you switch the lens to manual focus will it confirm focus at the widest focal length?

ImageX Photography · May 4, 2011

ziggy53 wrote: »

If you switch the lens to manual focus will it confirm focus at the widest focal length?

I don't know, Ziggy.

Refer to this thread to see why. http://www.dgrin.com/showthread.php?t=196650

The problem MAY be related because it just started.

FLYING EYEBALL · May 5, 2011

I know its gonna sound weird...but, are you using aftermarket batteries?

The only time I've had focus problems it was using 3rd party batteries.

Matthew Saville · May 5, 2011

Definitely use AF-S (single focus) when shooting wide angle and near-infinity, it will give you a lot better consistency.

And also, on a crop sensor at wider angles you can definitely have issues. I had the Nikon 17-55 even, and it needed focus calibration all the time especially at the wider end.

I guess it's just the fact that you've such tight tolerances when shooting on a crop sensor at a wide angle. Even a 0.5% error in focus, wide open at f/2.8 expecially, will throw focus off more than enough to totally kill fine detail. That's part of what makes full-frame, and medium format for that matter, so much more forgiving when it comes to focus. Much more "lose" tolerances...

Either way, keeping things calibrated is always going to be necessary. Good luck!
=Matt=

ziggy53 · May 5, 2011

ImageX Photography wrote: »

I don't know, Ziggy. Refer to this thread to see why. http://www.dgrin.com/showthread.php?t=196650

The problem MAY be related because it just started.

In addition to the visual AF confirmation your camera should be capable of audible AF confirmation. If you have the Menu item d1 set to High or Low, set the lens switch to Manual and see if you get focus confirmation with the lens set to the widest focal length.

Also, if you have a protective filter for the lens, try taking that off. Sometimes the filter can be detected at the widest lens setting and the camera may attempt to focus on the filter itself (which it cannot do, of course.)

ImageX Photography · May 5, 2011

Matthew Saville wrote: »

Definitely use AF-S (single focus) when shooting wide angle and near-infinity, it will give you a lot better consistency.

And also, on a crop sensor at wider angles you can definitely have issues. I had the Nikon 17-55 even, and it needed focus calibration all the time especially at the wider end.

I guess it's just the fact that you've such tight tolerances when shooting on a crop sensor at a wide angle. Even a 0.5% error in focus, wide open at f/2.8 expecially, will throw focus off more than enough to totally kill fine detail. That's part of what makes full-frame, and medium format for that matter, so much more forgiving when it comes to focus. Much more "lose" tolerances...

Either way, keeping things calibrated is always going to be necessary. Good luck!
=Matt=

Thanks, Matt. I always use AF-S for still subjects and in the center when I need a strong lock.... such as trying to figure this issue out at infinity. I believe that the problem I am having is lens calibration issue. I've only been at this stuff for a year or so and haven't ran into the problem until now. Like I said, it's ONLY at the wide end(17mm) and it's basically like the lens is just having a hard time "seeing". Zoom in a few mm and all is well. I figured it was a calibration issue since I could dial in a lot of negative fine tune and it would start locking again.

ImageX Photography · May 5, 2011

ziggy53 wrote: »

In addition to the visual AF confirmation your camera should be capable of audible AF confirmation. If you have the Menu item d1 set to High or Low, set the lens switch to Manual and see if you get focus confirmation with the lens set to the widest focal length.

Also, if you have a protective filter for the lens, try taking that off. Sometimes the filter can be detected at the widest lens setting and the camera may attempt to focus on the filter itself (which it cannot do, of course.)

Thanks, Ziggy. I do have my beeps turned on for confirmation.... and pull my filters off to give it the brightest clear view possible when trying to figure this out. I even tried live view zooming to see what was going on with the focus. It just acts like it needs a hair more infinity focus adjustment to focus at the wide end.... but it is at the stop already. It sounds like it's calibration time.

Anyone know how much Tamron charges for this?

PS I don't think my camera will give me Beeps at all when in manual focus. The whole issue has been harder to figure out without my view finder info display working.

FLYING EYEBALL wrote: »

I know its gonna sound weird...but, are you using aftermarket batteries?

The only time I've had focus problems it was using 3rd party batteries.

I have a mixture of both. I will make it a point to test things with Nikon batteries only. Thanks.

Matthew Saville · May 6, 2011

ImageX Photography wrote: »

Thanks, Matt. I always use AF-S for still subjects and in the center when I need a strong lock.... such as trying to figure this issue out at infinity. I believe that the problem I am having is lens calibration issue. I've only been at this stuff for a year or so and haven't ran into the problem until now. Like I said, it's ONLY at the wide end(17mm) and it's basically like the lens is just having a hard time "seeing". Zoom in a few mm and all is well. I figured it was a calibration issue since I could dial in a lot of negative fine tune and it would start locking again.

Yeah, unfortunately that' the nature of the zoom "beast", especially on crop sensors for some reason. Perfect calibration at the wide end will mess up the telephoto end, and vice versa. My Nikon 17-55 had a serious issue with this; it required -20 at the wide end and zero at the tele end, so I usually just settled for -10 and slightly soft images. Meh. I don't miss that lens, and I feel sorry for whoever stole it! :-P

=Matt=

ImageX Photography · May 6, 2011

Matthew Saville wrote: »

I don't miss that lens, and I feel sorry for whoever stole it! :-P

=Matt=

! That's funny. Still sucks though!

Yeah, I just dialed in negative fine tune to see what would happen.... and it starts locking again. No way will I settle for softness though and looks like I gotta send my grey Tammy in for calibration.

DO you know how much it usually costs for calibration? I may wait a bit because it's only at infinity and at 17mm. I can deal with it for awhile yet I guess.

Matthew Saville · May 8, 2011

ImageX Photography wrote: »

! That's funny. Still sucks though!

Yeah, I just dialed in negative fine tune to see what would happen.... and it starts locking again. No way will I settle for softness though and looks like I gotta send my grey Tammy in for calibration. DO you know how much it usually costs for calibration? I may wait a bit because it's only at infinity and at 17mm. I can deal with it for awhile yet I guess.

With a third party I'm just not sure what it would cost; obviously you can't send a Tamron lens in to Nikon, so the question is, will Tamron require you to send the camera in to THEM? Maybe, I don't see how you could get a really accurate calibration without it. When getting my Nikon 17-55 calibrated, I always left the body there with it, and it cost $j100-200. (And even then, they didn't solve the problem at all the first time, and I had to prove the issue to them right there in the shop when they tried to tell me it was fixed. Hah.

ImageX Photography · May 9, 2011

Matthew Saville wrote: »

With a third party I'm just not sure what it would cost; obviously you can't send a Tamron lens in to Nikon, so the question is, will Tamron require you to send the camera in to THEM? Maybe, I don't see how you could get a really accurate calibration without it. When getting my Nikon 17-55 calibrated, I always left the body there with it, and it cost $j100-200. (And even then, they didn't solve the problem at all the first time, and I had to prove the issue to them right there in the shop when they tried to tell me it was fixed. Hah.

It's a good coincidence you just posted this... about the body. I was shooting an easy target wide open today.... and just look.

It's an HDR image but still. It looks like back focus to me and this was with my 70-200.

Is it possible that my isues are with the body? I dropped my camera about a month ago. It seemed to be fine though and I have taken sharp pics since and directly after the drop.... like below. I am really wondering now if it's the body.

PS Wow, that's a lot $$$ to have them calibrate. Glad you knew enough to make them fix things right!

Wide angle focus problem

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