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07-19-2013, 12:06 PM - 1 Like   #31
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I think Pentax should extend the warranty on these lenses. I have had mine for four years and its SDM bit the dust after six months of use and then it has been fine since that time. Never know if it will bite the dust tomorrow, but for weather sealing and 16mm, there just isn't much else out there...

(shot in the rain at Cincinnati).




07-19-2013, 12:12 PM   #32
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QuoteOriginally posted by snake Quote
Most people can't afford that kind of downtime. I know I can't give up my 17-50 for repairs for months at a time. And in my case, Tamron is nearby in my country, plus I got a 5 year warranty.
True, that's the bad thing, I end up using other lenses that somehow overlap, and even the kit 18-55WR.
07-19-2013, 05:38 PM   #33
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Having owned the tamron for four years i can say the tamron has shockingly bad build quality with the front element continuously coming lose and the poor focussing performance too with regular hunting under low life.

Since having the 16-50mm which I bought used the build quality is excellent and the focussing speed is accurate and fast on my k-5 mkii, mki and the k-01. The rendering if this lens is head and shoulders above the tamron.
07-19-2013, 07:48 PM   #34
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QuoteOriginally posted by tomwil Quote
Is this comparative review the one you are mentioning, or is there another review now missing?
No, the review was located at http://servis-doma.net/pentax-forum/viewtopic.php?f=11&t=25.

It was very informative, showing examples at different zoom lengths, comparing the bokeh, etc.

EDIT: The "WayBack Machine" stored a copy of the post.

07-22-2013, 07:34 AM   #35
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QuoteOriginally posted by CRPhoto Quote
As with most of the SDM stories, my 16-50 started great. It started acting weird so I sent it to the local Pentax. They basically performed an adjustment and cleaning. If worked ok but then after a year it started acting up again. I successfully unjammed the SDM once on my 16-50 it worked for a few months but finally I was annoyed of the unreliability of the AF system. Finally, I decided to send it to CRIS for repairs. They got it in December and started working on it. Quickly they told me that the repairs needed were only possible in Japan, so after a $60 shipping fee, it went. By January I got the estimate...$240. So I said yes. Just a few days ago I got the email that my lens was ready and got the grand total. But first, here's what was replaced:

"REPLACED COVER FRAME
REPLACED ZOOM RING
REPLACED CAM RING
REPLACED JOINT RING
REPLACED EXTERNAL PARTS
REPLACED MOTOR
REPLACED PC BOARD
ADJUSTED TO MANUFACTURERS SPECIFICATIONS
GENERAL CHECK AND CLEAN"

The total cost was $332, which I find acceptable because it looks like a lot of replaced parts! and of course, if it works perfectly then I'll be happy with the investment! The lens is scheduled to arrive next week but I will be able to use it by the end of the month (because I had it ship to a Miami address instead to Costa Rica). Once I'll get it I'll let you know how it turned out. I just wanted to share my excitement to get my precious zoom back again!
you said you unjammed the 16-50 how did you do that ? mine has started acting up after having it for 4 years. any help you or anyone can offer would be geatly appreciated.
07-22-2013, 08:08 AM   #36
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QuoteOriginally posted by snake Quote
There was no argument.
I guess what he's saying is, we don't really care about some German engineer, or American or Japanese one or whatever. Everyone is entitled to an opinion, and that's fine, but many of us are really sick of constant anti-SDM opinions. Many of us own SDM lenses that function perfectly, in my case even though sometimes abused. In all the SDM discussions to date, not one person has been able to show stats suggesting the SDM failures are worse than failures in an Canon or Nikon lens, or any lens anywhere for that matter. I don't expect any SDM or any electronic lens lens to compare with the reliability of the screw drive lenses in smaller less complex lenses, so just buying SDM in the first place means you're accepting a higher likely hood of repair. More small moving parts, more electronic parts means more failures. Of course, your German engineer expert told you that didn't he? I'd hate to be thinking you're taking advice from someone incapable of looking at the issue objectively. Without some solid numbers on the percentages of failures, I'm not sure how you even do that? Pentax said there was a problem and that the new mechanisms are improved, but they never said the SDM failure rate was un-acceptable by industry standards. Pentax's standards seem to be higher than the industry as a whole, they could be un-acceptable to Pentax and still be within industry norms.

Please, no more factless slamming of SDM. Information is good. Allegations based on incomplete information are not appreciated. Especially if they come from a third party German engineer who's information can not even be examined to see if he followed even the minimum standards of objectivity.
07-22-2013, 08:35 AM   #37
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QuoteOriginally posted by normhead Quote
I guess what he's saying is, we don't really care about some German engineer, or American or Japanese one or whatever. Everyone is entitled to an opinion, and that's fine, but many of us are really sick of constant anti-SDM opinions. Many of us own SDM lenses that function perfectly, in my case even though sometimes abused. In all the SDM discussions to date, not one person has been able to show stats suggesting the SDM failures are worse than failures in an Canon or Nikon lens, or any lens anywhere for that matter. I don't expect any SDM or any electronic lens lens to compare with the reliability of the screw drive lenses in smaller less complex lenses, so just buying SDM in the first place means you're accepting a higher likely hood of repair. More small moving parts, more electronic parts means more failures. Of course, your German engineer expert told you that didn't he? I'd hate to be thinking you're taking advice from someone incapable of looking at the issue objectively. Without some solid numbers on the percentages of failures, I'm not sure how you even do that? Pentax said there was a problem and that the new mechanisms are improved, but they never said the SDM failure rate was un-acceptable by industry standards. Pentax's standards seem to be higher than the industry as a whole, they could be un-acceptable to Pentax and still be within industry norms.

Please, no more factless slamming of SDM. Information is good. Allegations based on incomplete information are not appreciated. Especially if they come from a third party German engineer who's information can not even be examined to see if he followed even the minimum standards of objectivity.
You're replying to something posted nearly 1/2 year ago. Not to mention, your reply is filled with errors and untruths. One of them I left in bold.
07-22-2013, 10:35 AM   #38
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QuoteOriginally posted by nitehntr Quote
you said you unjammed the 16-50 how did you do that ? mine has started acting up after having it for 4 years. any help you or anyone can offer would be geatly appreciated.
I took the mount apart and with a screwdriver moved the little SDM motor. I read this somewhere, but I can remember where. It worked but then it failed again and that's when I send it to CRIS for repairs and they send it to Japan.

07-22-2013, 03:22 PM   #39
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QuoteOriginally posted by snake Quote
You're replying to something posted nearly 1/2 year ago. Not to mention, your reply is filled with errors and untruths. One of them I left in bold.
That would probably make it one of my more relevant posts....

The German engineer was not a part of this discussion, that makes him third party, if he wasn't he'd be on here answering questions.... if you're going to be critical of my perspective at least understand enough to be accurate. If there are other suspected errors or untruths errors or untruths I'd be happy to clarify those for you as well, but so far you're shooting 0 for 1. I'll stand behind any statement made above and will be happy to explain how I came to the conclusion.
07-23-2013, 12:19 AM - 1 Like   #40
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QuoteOriginally posted by normhead Quote
That would probably make it one of my more relevant posts....

The German engineer was not a part of this discussion, that makes him third party, if he wasn't he'd be on here answering questions.... if you're going to be critical of my perspective at least understand enough to be accurate. If there are other suspected errors or untruths errors or untruths I'd be happy to clarify those for you as well, but so far you're shooting 0 for 1. I'll stand behind any statement made above and will be happy to explain how I came to the conclusion.
The "German engineer" was/is a Pentax employee.

The text is available for people to make their own mind up on the content, not that of an extreme apologist.

I have the situation of being based in at least three countries, and regularly floating between three languages. All three countries (France, US, Germany (which should including Switzerland and Austria for the purpose of discussion due to the single distributor here) ) report the same thing about SDM and repeated repairs. Repaired lens returns, it fails.

In my case, local dealers issued warnings when I was planning on Pentax. They told me the exact story going on and what the terms would be WHEN repair assistance is needed. And this was a Pentax "Premium" retailer, who won't stock SDM lenses and gives warnings when one plans on buying one. They've been apparently left holding the bag on return service several times, so they charge up front service costs now because the situation has gotten pretty bad.
07-23-2013, 04:37 AM   #41
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Holy poop, I read the same report you did. What different conclusions two people can come to reading the same report.... if pick pocket sees a saint, all he sees are his pockets. Or to put it more bluntly, expectations alter conclusions. As for dealers, you mean the same dealers who regularly push Nikon and Canon over Pentax product? And now we are going to start second guessing the decisions of various Pentax dealers based on Pentax users who got spooked by all the bad press around SDM and wouldn't pay for service on their lenses? Listen snake.... I don't know what your problem is here, but I hope you get it straightened out soon.

There is at least one source... the lens rental place who says Pentax have the lowest failure rate in the industry... until you can incorporate that into the train of thought that goes round and round in your head you're missing part of the big picture, and probably just punching the air. SDM was probably the poorest piece of Pentax engineering in recent history... but they still managed have the best overall dependability rating in the only source I've seen for that type of stat. What does that say about the competition?
07-23-2013, 09:38 AM   #42
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QuoteOriginally posted by normhead Quote
There is at least one source... the lens rental place who says Pentax have the lowest failure rate in the industry...
LensRentals.com does not carry Pentax equipment.

If you are referring to the LensPlay survey, note that
  1. they appear to be asking for lenses that arrive with a defect. There is no indication that they are looking for defects that develop after a year of purchase.
  2. they provide several threads to the validity of their results.
One of those threads is of high relevance here:
"The probabilities assume that the distribution of defective SLR lenses is completely random, i.e. doesn't depend on which lens you chose or where it is shipped from. This may not be true, in fact it probably isn't. Some models may be more likely to show defects that others. "
This assumption is completely false for Pentax lenses, some of which are rock solid (most screw drive lenses) while others can be terrible.

We don't even know how many users with SDM lenses participated in this survey.

As in other cases -- when using images for sharpness comparisons that were never meant to be used for this purpose -- you seem to have a propensity to incorrectly interpret data.

You are basically trying to paint a picture that the reliability of a DA* 16-50/2.8 is industry leading. That's just laughable IMHO.

P.S.: Normhead, did you notice that the OP's 16-50 failed again after a few months of the repair?
I've read such deplorable stories over and over again. Now that dual-drive lenses like the 16-50 and 50-135 can be turned into screw drive lenses by patching the lens EPROM, they become more interesting again. But before we had this option, as pure SDM lenses, they were best avoided by those who need dependable AF.

Last edited by Class A; 07-23-2013 at 09:48 AM.
07-23-2013, 09:50 AM   #43
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QuoteOriginally posted by Class A Quote
LensRentals.com does not carry Pentax equipment.
Yes, they do carry Pentax:
LensRentals.com - Rent Pentax equipment
07-23-2013, 10:03 AM - 1 Like   #44
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QuoteOriginally posted by CRPhoto Quote
Yes, they do carry Pentax:
LensRentals.com - Rent Pentax equipment
Interesting.

Do you know when they started carrying Pentax?

I've seen many of the "Lens Repair Data" reports by LensRentals and Pentax was never mentioned in those.
Either they didn't carry Pentax yet, or the rental numbers were so low that the statistics did not make it into the report. They require a certain rental volume in order to obtain statistical significance.

So the fact that Pentax lenses are not among those listed to have a high failure rate most likely does not mean that they have proven to have a low failure rate.

EDIT:
From the 2012 Lens Repair Data report:
"The following lenses or cameras we carry were NOT evaluated because we have less than 10 copies or they were in stock less than 3 months.

...
All Leica, Voigtlander, Pentax, Fuji, and Schneider lenses
"
Before 2012, Pentax isn't mentioned at all.

Last edited by Class A; 07-23-2013 at 10:38 AM.
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