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10-12-2016, 09:46 AM   #1
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DA* 60-250 question...

When going from near to infinity focus, or at least a distant focus, the lens hunts, and focuses in four or five 'steps', for lack of a better description. However, when going from infinity (or distant) to near, is thinks for a split second, and then locks on focus immediately.

Do other owners think that there is a problem with my lens? Does your do this? This lens is barely three months old, and it has already had SDM failure and replacement under warranty.

Great lens, but this makes me think the motor is faulty again.

Thanks,
Cameron

10-12-2016, 10:41 AM   #2
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What body are you using? AF mode? AF points? On K-5IIs and K-3 my 60-250 does not behave like that. Totally possible your lens is having function trouble but I'd suggest trying all combinations of AF modes and AF point selection to see if the bad behavior is consistent with all camera settings.
10-12-2016, 12:25 PM   #3
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Yep. Is this AF.S, AF.C, Auto-select 11, Single point, Live view? And which camera? Was the lens modified in any way, does it have a filter mounted?
Focusing in big steps is not completely normal, but it really depends on the scene, light, contrasts.
First things to do is make sure lens mount is not damaged, not dirty. Then check front and back glass of lens. And remove any filter. Then you do a systematic test in good daylight with a big, contrasty subject and AF.S, single point. Switch to MF to defocus between test shots. Best to use tripod, 2 sec timer, lowest ISO.

Last edited by Na Horuk; 10-12-2016 at 12:31 PM.
10-13-2016, 11:04 AM   #4
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Done all that...

QuoteOriginally posted by JeffB Quote
What body are you using? AF mode? AF points? On K-5IIs and K-3 my 60-250 does not behave like that. Totally possible your lens is having function trouble but I'd suggest trying all combinations of AF modes and AF point selection to see if the bad behavior is consistent with all camera settings.
QuoteOriginally posted by Na Horuk Quote
Yep. Is this AF.S, AF.C, Auto-select 11, Single point, Live view? And which camera? Was the lens modified in any way, does it have a filter mounted?
Focusing in big steps is not completely normal, but it really depends on the scene, light, contrasts.
First things to do is make sure lens mount is not damaged, not dirty. Then check front and back glass of lens. And remove any filter. Then you do a systematic test in good daylight with a big, contrasty subject and AF.S, single point. Switch to MF to defocus between test shots. Best to use tripod, 2 sec timer, lowest ISO.
I thought you'd notice that it's a K3ii. Tried ALL autofocus modes and points. This problem is occurring outside in strong light, from iso 100 on up. No problems with any other lenses, including screwdriver DA limiteds, a 10-17 fisheye, and the 16-85. Focussing on a strong scene with lots of verticals/horizontals/diagonals in distance and up close - nothing 'tricky. It goes 'brap brap brap brap' and focusses in stages from near to far, but goes directly onto the subject from far to near. Very strange. I think it has to go back.

At what point do we declare it a lemon? Optically, it is magnificent, but this focus problem sucks.

Cheers,
Cameron

10-13-2016, 11:19 AM   #5
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Yes, that sounds wonky. Probably needs repair.
10-13-2016, 04:17 PM   #6
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Interesting to read this discussion. I just got a used 60-250 yesterday in very nice condition. It does the same thing when focusing from close to far, it makes a few readjustments. I also have a k3ii. To me it looks similar to how the 100mm macro wr readjusts a few times and so I didn't give it too much thought. It also didn't focus right away the first time I used it, but since then it's been working fine. (it has 6 months of warranty)

Edit: actually all my screwdrive lenses readjust a few times after roughly reaching focus, it's just that they move much less and I can't see it, but it's still audible
10-14-2016, 11:10 AM   #7
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Thanks....

QuoteOriginally posted by aaacb Quote
Interesting to read this discussion. I just got a used 60-250 yesterday in very nice condition. It does the same thing when focusing from close to far, it makes a few readjustments. I also have a k3ii. To me it looks similar to how the 100mm macro wr readjusts a few times and so I didn't give it too much thought. It also didn't focus right away the first time I used it, but since then it's been working fine. (it has 6 months of warranty)

Edit: actually all my screwdrive lenses readjust a few times after roughly reaching focus, it's just that they move much less and I can't see it, but it's still audible
Does your go directly to focus from far to near, or does it hunt? Mine doesn't.

Thanks,
Cameron
10-14-2016, 11:24 AM   #8
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It never hunts in the sense of going through most / all of the focus range. I could get it to overshoot when focusing from far to near: very dim light, reasonably low contrast target. It overshoots just a very slight amount during the initial focus and then readjusts. From close to far it always stops a little short of the goal and then quickly readjusts, it's more noticeable at longer focal lengths. The behavior is very consistent if I keep the same target and lighting. So overall it's not ideal, but think it's too consistent to be faulty. I guess I'll find out in the coming months, the lens is used but I just got it the other day.

10-18-2016, 12:10 PM   #9
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Thanks

Any other insights?

Cheers,
Cameron
10-20-2016, 04:47 PM   #10
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Unrelated question on this lens:

I rented a copy from Lens Rentals for F1 this weekend, figuring it would be nice to have a long tele for shots from our seats in the stands. It arrived today and the zoom ring feels tight and almost gritty, especially between 60-135 according to the lens barrel. Is this copy in bad shape and should I report this to LR or does the zoom always feel this...severe?
10-21-2016, 11:17 AM   #11
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Mine's pretty 'tight'...

...and there is a lot of zoom 'huffing' as air escapes from the lens.

Cheers,
Cameron
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