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03-20-2010, 07:52 AM   #31
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QuoteOriginally posted by creampuff Quote
It's one thing to rant about a product defect, but too much negativity rehashing how crappy SDM is and frankly the sentiment starts wearing thin.
But you're a well-known SDM apologist. The constant arguing that SDM is a flawless technology is wearing a bit thin.

SDM is one tiny aspect of Pentax. It's not enough to drive me away from Pentax, only from SDM.

03-20-2010, 07:54 AM   #32
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QuoteOriginally posted by philbaum Quote
The ball contacts in the mount and the pz contacts sometimes get dirty from caps that don't completely cover them, please make sure that these are cleaned as well. These can cause SDM failure symptoms as some have reported.
and if these are clean and still doesn't work?
03-20-2010, 10:18 PM   #33
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QuoteOriginally posted by aleonx3 Quote
I just did test my DA* 50-135mm again, it is working just fine as it should; also put the same lens on the K100D, the screw drive motor works fine too. However, the SDM motor is better (quieter and quicker).
QuoteOriginally posted by aleonx3 Quote
Jeffrey, I tried the lens on both K100D (screw drive only) and K10D (SDM), SDM motor is quieter and quicker for sure in my test.
You can't really compare AF speed between the screwdrive K100d and the SDM of a later camera. The K100d had a screwdrive motor with less power than the K10/20 and K7. Plus the K100d uses AA batts...

To really compare focus speed between Screwdrive and SDM, you would need to do it on the same body.... OH wait, we can't!
03-20-2010, 10:37 PM   #34
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QuoteOriginally posted by Igilligan Quote
To really compare focus speed between Screwdrive and SDM, you would need to do it on the same body.... OH wait, we can't!
Sure we can. Take a K10D with firmware 1.20, test auto focus. Upgrade to 1.30, test again. Voila, valid results.

Or... fry the SDM contacts like someone else did to his K20D (I forget his name now).

03-21-2010, 07:09 AM   #35
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QuoteOriginally posted by GoremanX Quote
..Or... fry the SDM contacts like someone else did to his K20D (I forget his name now).
That would be Peter Zack. But it was an accident...
03-21-2010, 07:37 AM   #36
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Gah my 3week old 50-135mm carked it tonight.

I can't even focus using the the focusing ring either.
03-21-2010, 08:58 AM   #37
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QuoteOriginally posted by C.W Tsorotes Quote
Gah my 3week old 50-135mm carked it tonight.

I can't even focus using the the focusing ring either.
Try the screw-drive by hand, you might be able to dislodge it. That's the only mechanism with a solid link.

03-21-2010, 09:02 AM   #38
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Yer I tried that, can get movement but it seems a tad tight.

Oh well no biggie, get it swapped over.
03-21-2010, 09:04 AM   #39
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QuoteOriginally posted by C.W Tsorotes Quote
Yer I tried that, can get movement but it seems a tad tight.
Shouldn't be tight at all. Mine turns practically by blowing on it. Definitely sounds like it jammed. Oh well, make sure you vote!

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/94076-da*50-13...o-problem.html
03-23-2010, 12:03 AM   #40
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QuoteOriginally posted by Russell-Evans Quote
This probably isn't SDM failure. Take a look at the contacts on the lens and insure that they are in working order. You want to look at both the contacts on the flange and the power contact.

Thank you
Russell
Thanks, this is the first thing I did, and didn't do anything.
Anyway, it's still working fine right now since I woke it up last week... we'll see.
It will be nice if Pentax would allow the use of the screwdrive just in case it fails...
03-29-2010, 07:21 AM   #41
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My DA* 50-135 SDM experience

I've tried hard to resist but now feel I should add my story...

I bought a 1 month old DA* 50-135 lens which, as it transpired, was a warranty replacement for a 2 month old lens that had had an SDM failure. I didn't know this at the time I purchased it but I had effectively bought a new lens that according to the seller hadn't been used at all.

Upon unpacking the lens and as the seller said, it appeared to be brand new. I mounted the new lens and sadly immediately found that focusing was problematic. There was no movement at all at first but then it seemed to free up after some manual winding of the focus ring throughout its range. Not right.

I sent this second lens in for warranty repair and after 2 months it was returned to me with "motor replaced" in the report. So two new lenses each with SDM failures from new - failures clearly not related to wear or abuse but rather just design/manufacturing failures. Not a good start!

Anyway, to cut to the chase this second (now repaired) lens also failed (absolutely stone dead focussing) on its very first outing so it was returned again under warranty.

This time CRK substituted a brand new lens this time instead of another repair attempt so I can't possibly complain about the service I guess apart from the 2 month initial repair period which really seemed excessive. The actual time on the bench could surely have only been a few hours at most.

I've had this 3rd lens a few weeks but haven't had an oportunity to mount it for an outing yet. Time will tell how it goes but I'm strangely resigned to wasting my $AUD1000 on it.
03-29-2010, 08:04 AM   #42
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I guess the SDM problem is too hit and miss to nail down. I bought my 50-135 new within a month of them first being released. In fact it was the first one I saw. I don't use it that often, and it rides in my camera case everywhere I go. mounted it the other day for the first time in months and it worked fine, on both my K10, and a friends KX. Perhaps climate has something to do with the SDM failure rate. Colorado is very dry, (and sometimes very cold). Maybe the issue is more of a corrosion problem due to humidity. Has anyone reported problems with SDM lenses that have been stored in humidity controlled lockers?
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