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07-17-2012, 10:04 AM   #76
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QuoteOriginally posted by Tom S. Quote
That is a rumor which has not been substantiated. Doesn't it strike you odd that three of Pentax's most popular zooms would exhibit this effect vs lenses that typically are not used as often? Using the logic of use it or lose it, don't you think the 200mm and 300mm would have topped the list for repairs?
I do see your point. I would also offer that the 300 is a prime and less complex mechanically. The highest rate of failure has been with the much more mechanically complex zooms. They may also be used more intensively but they are also more complex and therefore may pose additional challenges to the SDM design fault thereby resulting in more failures.

07-17-2012, 10:20 AM   #77
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QuoteOriginally posted by Tom S. Quote
That is a rumor which has not been substantiated.
No, it's a fact that has been reported by users in this forum, e.g.,

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/134722-da-50-1...ml#post1406384
07-17-2012, 12:13 PM   #78
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QuoteOriginally posted by lytrytyr Quote
No, it's a fact that has been reported by users in this forum, e.g.,

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/134722-da-50-1...ml#post1406384
Re-read your link. Ben said he didn't use it once. That doesn't mean sitting caused it to go bad, it means it was probably bad to begin with. Come back when you have proof that it's a fact and not supposition.
07-17-2012, 04:09 PM   #79
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QuoteOriginally posted by Tom S. Quote
Re-read your link.
Read more of that thread, e.g:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/134722-da-50-1...ml#post1504864

QuoteOriginally posted by Tom S. Quote
Come back when you have proof that it's a fact and not supposition.
If you know for sure what is and isn't wrong with these SDM lenses,
please let Pentax know, so they can fix it!

07-17-2012, 04:16 PM   #80
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QuoteOriginally posted by Tom S. Quote
That doesn't mean sitting caused it to go bad, it means it was probably bad to begin with. Come back when you have proof that it's a fact and not supposition.
The lens was reportedly repaired by Pentax and returned to Benjamin.
Are you supposing that Pentax did not fix
a lens that was sent to them for repair
by one of their high-profile professional users?
07-18-2012, 04:33 AM   #81
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QuoteOriginally posted by lytrytyr Quote
The lens was reportedly repaired by Pentax and returned to Benjamin.
Are you supposing that Pentax did not fix
a lens that was sent to them for repair
by one of their high-profile professional users?
The lens was sent to a Pentax repair facility. For more posts on some of Pentax repair facilities screw ups, search the forum, as there have been many posts from people in the US, Canada and Europe complaining about sending in cameras and lenses with mixed results from failure to fix initial problems to causing other problems. In Ben's case, I suspect the lens was never fixed and sent back by mistake. It happens.
07-18-2012, 04:44 AM   #82
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QuoteOriginally posted by lytrytyr Quote
Read more of that thread, e.g:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/134722-da-50-1...ml#post1504864


If you know for sure what is and isn't wrong with these SDM lenses,
please let Pentax know, so they can fix it!
From your link:

QuoteOriginally posted by wizofoz Quote
I read this thread about yet another SDM failure, feeling sympathy for the OP. "Poor Sod" I thought. I've never had a problem with my 50-135. I love that lens. Reading yet again about SDM failures when the lens has not been used, I took mine out of it's case where it has been for the fortnight since I last used it, mounted it on the K-5 and .....it's dead.

Hmm, tried the K-7, the K-x and even a 1.4x TC (desperate measure, I realise) ...nothing.

Looks like I'm another victim of the SDM failure. Bugger. This means sending the lens to Japan, as there is no way of fixing it in Oz, as far as I'm aware.
So, every lens not used within a two week span is liable to fail? That makes the problem even worse than originally suspected, doesn't it? It also flies in the face of the statistics of failure rates. As I have repeatedly pointed out, the longer fixed focal length lenses are undoubtedly used less often than the more popular zoom lenses, thereby sitting idle more often, yet the reported failure rate for them is lower. Care to explain that?
07-18-2012, 07:38 AM   #83
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QuoteOriginally posted by Tom S. Quote
As I have repeatedly pointed out, the longer fixed focal length lenses are undoubtedly used less often than the more popular zoom lenses, thereby sitting idle more often, yet the reported failure rate for them is lower. Care to explain that?
My speculation: the element group being moved in them
is lighter than in the more troublesome zoom lenses.

Unfortunately, as I hinted in my earlier reply,
none of us know the answer,
so all we can do is hypothesize.

Sadly, Pentax seem to be as helpless as we consumers are.
But at least we can use the collective wisdom of this forum
to try to gather some impressions.
One of those impressions is that disuse worsens the problem,
and not just through allowing electrical discharge.
It may be some grease hardening,
or it may be some other effect.

My own market response has been to avoid SDM lenses.
I bought 58/1.4 and 90/3.5 Voigtlaenders instead of the 50-135/2.8,
and a Tamron 17-50/2.8 A16P instead of the 16-50/2.8.

07-18-2012, 07:49 AM   #84
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QuoteOriginally posted by lytrytyr Quote
My speculation: the element group being moved in them
is lighter than in the more troublesome zoom lenses.

Unfortunately, as I hinted in my earlier reply,
none of us know the answer,
so all we can do is hypothesize.

Sadly, Pentax seem to be as helpless as we consumers are.
But at least we can use the collective wisdom of this forum
to try to gather some impressions.
One of those impressions is that disuse worsens the problem,
and not just through allowing electrical discharge.
It may be some grease hardening,
or it may be some other effect.

My own market response has been to avoid SDM lenses.
I bought 58/1.4 and 90/3.5 Voigtlaenders instead of the 50-135/2.8,
and a Tamron 17-50/2.8 A16P instead of the 16-50/2.8.
I don't think Pentax is as clueless as they may seem. Hoya may have ignored the problem (along with several other problems people have reported with various camera bodies) knowing they were going to divest themselves of the business. Ricoh inherited the issue(s) when they bought Pentax and I'm hoping, as I'm sure many others are, that they are seeking a cure.
07-18-2012, 07:56 AM   #85
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QuoteOriginally posted by Tom S. Quote
I don't think Pentax is as clueless as they may seem. Hoya may have ignored the problem (along with several other problems people have reported with various camera bodies) knowing they were going to divest themselves of the business. Ricoh inherited the issue(s) when they bought Pentax and I'm hoping, as I'm sure many others are, that they are seeking a cure.
Honest question so don't just shoot me. Was the last silent motor lens released the 18-135? If so, perhaps the DC motor, which has been trouble free based on the database responses, was Pentax's answer?
07-18-2012, 08:05 AM   #86
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QuoteOriginally posted by Docrwm Quote
Honest question so don't just shoot me. Was the last silent motor lens released the 18-135? If so, perhaps the DC motor, which has been trouble free based on the database responses, was Pentax's answer?
I don't know, but if that is/was the case, why hasn't it been adapted to the other lenses?


BTW: I only shoot dishonest questions!
07-18-2012, 09:50 AM   #87
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QuoteOriginally posted by Tom S. Quote
I don't know, but if that is/was the case, why hasn't it been adapted to the other lenses?


BTW: I only shoot dishonest questions!
There hasn't been another silent motor lens released since so perhaps they will continue to use this design instead of SDM. Let us hope so.
07-18-2012, 12:22 PM   #88
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I just don't think Pentax has any answers with regard to SDM. My guess is that the lenses are more complex than the primes and the motors are under powered for what is needed. Pentax should release version two of the 16-50, 50-135 with faster motors and a little better optics in the case of the 16-50. In the case of the 50-135, if the SDM goes out on my copy, I would get it fixed, because optically, it is just awesome.
07-18-2012, 01:24 PM   #89
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QuoteOriginally posted by Tom S. Quote
Where in my post did I say anything about numbers sold? I'm talking about usage. Most people who buy a 60-250 will use it a lot more than people who buy a 300. My point, which obviously went over your head, was if people used the 200mm and 300mm as much as the various zooms were used, the failure rate would likely been much higher for those lenses. I suspect the double digit failure ratings for the three zooms listed would extrapolate (google it if you don't understand it) to the other SDM lenses if those other lenses received the same amount of usage (not sales) the three zooms with the highest rate of failures received.

I know you are a dyed in the wool fan boy of Pentax, and you refuse to admit there's a problem, but don't let it affect your reading comprehension.
Funny how every here has an opinion about me, I would have several camera brands by now in all shape and sizes
Anyway, where did i said there wasn't a problem?

I thought you means less people use a 300mm lens compared to how many use the 60-250mm, sorry i read your comment wrong but that has nothing to do how smart or stupid i'm so don't talk me down.
Anders kan ik ook gewoon in mijn eigen taal gaan typen dan mag jij het lekker gaan vertalen, ben benieuwt hoe dat je bevalt.

Back to topic, i would love to see where you base that data on that the 300 is used less then the 60-250, i've never seen any figures about that.
07-18-2012, 01:27 PM   #90
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QuoteOriginally posted by Tom S. Quote
[As I have repeatedly pointed out, the longer fixed focal length lenses are undoubtedly used less often than the more popular zoom lenses, thereby sitting idle more often, yet the reported failure rate for them is lower. Care to explain that?
What about the DA*55 how do you explain that?
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