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07-14-2008, 11:26 AM   #1
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Tamron 18-250 won't focus - PANIC !

As we're only two weeks from the big EAA air event at Oshkosh, my 18-250 (on a K10D) has decided it won't focus. It generally just saws back and forth a few times and then gives up.

This is true regardless of center vs. select vs. whatever. True in good light and medium light, indoors or outdoors.

My Sigma 10-20 and 17-70 seem to work fine on that body.

But that's left me without a long lens for my biggest photo event of the year - the primary reason for the K10D's purchase last September. Yikes!

Does anyone have any bright ideas on what can be done short of a stay at the lens hospital? Last time it took about three weeks - weeks I don't have. I'm not suggesting that I learn lens repair but I'm wondering if there is some error or condition or setting I've simply overlooked. I'm pretty good at ignorance.

Thanks in advance for your help and/or sympathy, my friends.

07-14-2008, 11:33 AM   #2
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Clean your contacts.?
Check if your in AF-C.?

Dave
07-14-2008, 11:33 AM   #3
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QuoteOriginally posted by glanglois Quote
As we're only two weeks from the big EAA air event at Oshkosh, my 18-250 (on a K10D) has decided it won't focus. It generally just saws back and forth a few times and then gives up.

This is true regardless of center vs. select vs. whatever. True in good light and medium light, indoors or outdoors.

My Sigma 10-20 and 17-70 seem to work fine on that body.

But that's left me without a long lens for my biggest photo event of the year - the primary reason for the K10D's purchase last September. Yikes!

Does anyone have any bright ideas on what can be done short of a stay at the lens hospital? Last time it took about three weeks - weeks I don't have. I'm not suggesting that I learn lens repair but I'm wondering if there is some error or condition or setting I've simply overlooked. I'm pretty good at ignorance.

Thanks in advance for your help and/or sympathy, my friends.
I'm not a true expert on this, but focusing is handled by the focus sensor in your K10D. My best guess is that there is something not right in the communication between the lens and the camera if other lenses work.
Try cleaning the lens / camera contacts with cotton and a little alcohol.

- Bert
07-14-2008, 01:48 PM   #4
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Here's what I've checked

Thanks for the advice - this group is wonderfully fast.

I did try it in AF-C and AF-S. No change. Manual works fine - to the extent that I have the time and can manually focus with these old, tired eyes. Not the optimum arrangement for aircraft in flight.

I've polished the contacts with a soft cloth but haven't used ETOH yet. I've been reserving it for medicinal purposes.

I'll try a better cleaning this evening if I can find time. I'm afraid I've been too busy with the 17-70 banging away at our first two grandchildren, Addy and Kate, who were born Saturday. All is well except that they seem to have acquired an aversion to the presence of a DSLR with a flash atop. Can't figure that out ....

07-15-2008, 01:57 AM   #5
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Congrats on becoming a Grandfather.
07-15-2008, 02:07 AM   #6
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NEVER use a flash when photographing babies! Their eyes aren't fully developed yet and can hurt them.
07-15-2008, 03:52 AM   #7
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QuoteOriginally posted by ftpaddict Quote
NEVER use a flash when photographing babies! Their eyes aren't fully developed yet and can hurt them.
This is a myth, I think you'll find.

Don't you think that if this were true, in this litigious age, flash units would only be sold with huge great warnings and publicity campaigns? And that there would be hundreds of thousands of eye-damaged kids all over the world?

Here's an interesting article.

There are lots of similar articles all over the net. But don't take my word for it - DYOR.
07-15-2008, 04:43 AM   #8
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QuoteOriginally posted by ftpaddict Quote
NEVER use a flash when photographing babies! Their eyes aren't fully developed yet and can hurt them.
Urban photographic myth propagated. No basis of truth.

07-15-2008, 04:54 AM   #9
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One other thought on the lens, not the baby's.

Does it do it just at the 18 and 250 marks or through out the whole range.

My 28-105 will not focus at the 28 or 105 marks, but moving it off those marks just a hair and it will focus.

Other than that, i'm at a loss.

Dave
07-22-2008, 09:37 PM   #10
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QuoteOriginally posted by glanglois Quote
As we're only two weeks from the big EAA air event at Oshkosh, my 18-250 (on a K10D) has decided it won't focus. It generally just saws back and forth a few times and then gives up.

My Sigma 10-20 and 17-70 seem to work fine on that body.

s.
So whatever is wrong, is wrong with the actual lens. There's a focus rod that has a slotted connection with the motor in the body. This runs through the bayonet joint via a slotted connection, male on one side, female on the other. You might look at this connection on the lens side and see if the connecting rod has been dinged in any way preventing the connection from sliding together when the lens is installed. If the metal is bent in some way, you might be able to straighten any bent metal with a small needle nose pliars. There might just be some particle in the slot preventing it going together. Have someone hold a vacuum nozzle near the work area if you're going to work on the slot to help pull any particles away from the lens. just a thought, more likely a dirty connection as others have suggested.

If you've bought any old lenses, they can be a source of dirt in the connection. the last 50mm prime i bought had a smear of dirt around the contacts area which i removed prior to putting it together with my K10.

Phil B.
07-23-2008, 07:18 PM   #11
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Solved - I think

Thanks for all the good thoughts. This is a great group. My responses:

The lens was new early last winter and was back at Tamron for excessive zoom creep in April.

The focus problem seems to have solved itself, after no more than taking the lens off and putting it back on yet again. That simple act may have cleaned a contact. Performance improved greatly, perhaps to normal function but less than perfection. Moderately low light is still trouble but that, I've heard, is endemic.

I then cleaned contacts again with isopropyl alc. No difference.

It now seems to generally focus OK with some infrequent minor chattering, even in bright light. But it's rare enough that I'm holding off on panic.

I usually shoot bounce flash for a wide variety of reasons. But I'll do another check on flash with babies. I'm not worried yet but it's worth a few minutes checking with the neonatalogist.

Thanks again. Next I'll post my Sigma problem. I think I have a lot to learn .....
07-24-2008, 03:05 AM   #12
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My father took flash pictures of my brother and I when we were only a few days old with his spotmatic (now mine) and either the Vivitar or Starblitz flash. Needless to say, they're cute pictures, and we're not blind. Granted I have less than perfect vision, but that's more due to genetics than anything else (Dad wore glasses too).
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