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07-10-2012, 10:22 AM   #16
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Tom take a look at this.

LensRentals.com - Lens Repair Data 2011

Wonderful isn't it... so the 5.6 % of the DA*60-250 is not bad in comparison, all the 70-200 lenses had double more problems so the grass is greener doesnt work.


some more interesting data.
- We kept repair statistics on camera bodies for the first time this year. I didn’t list them because failure rates for all bodies were about the same. Pro, prosumer, consumer, brand, it didn’t matter much, about 18% of bodies required repair during the year.
- As with our last report, it seems some of the sharpest lenses may also be the most difficult to keep working. The Canon 70-200 f/2.8 IS MkII, the Nikon 70-200 f/2.8 VRMkII, and the Sigma 50-500 OS all continue on the list.
- Newly released lenses tend to have higher repair rates. IS lenses have higher repair rates. Zooms have higher repair rates. Newly introduced IS zoom lenses would seem to a repair just waiting to happen. But then that’s why they give warranties.



Last edited by Anvh; 07-10-2012 at 10:29 AM.
07-10-2012, 10:28 AM   #17
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QuoteOriginally posted by Anvh Quote
Tom take a look at this.

LensRentals.com - Lens Repair Data 2011

Wonderful isn't it... so the 5.6 % of the DA*60-250 is not bad in comparison, all the 70-200 lenses had double more problems so the grass is greener doesnt work.
Perhaps. It's important to note that Lens Rentals does not rent Pentax equipment.
07-10-2012, 10:43 AM   #18
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Just out of interest, does anyone know whether it is possible to fool the camera into using the screw mechanism by covering the SDM contacts? I don't want to test this directly myself because if it ain't broken, don't fix it!
07-10-2012, 10:48 AM   #19
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QuoteOriginally posted by top-quark Quote
Just out of interest, does anyone know whether it is possible to fool the camera into using the screw mechanism by covering the SDM contacts? I don't want to test this directly myself because if it ain't broken, don't fix it!
That has been asked for years, there was even an online petition to Pentax to allow that through menus in a firmware update, and the answer is still - no.

07-10-2012, 11:04 AM   #20
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QuoteOriginally posted by Docrwm Quote
That has been asked for years.
It even arose in posts #8 and #9 of this very thread.
07-10-2012, 11:51 AM   #21
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QuoteOriginally posted by top-quark Quote
Just out of interest, does anyone know whether it is possible to fool the camera into using the screw mechanism by covering the SDM contacts? I don't want to test this directly myself because if it ain't broken, don't fix it!
The problem is that all AF systems are connected so if you do had a non working SDM you've no idea how that will influence the other systems, you could very well break the lens more and the camera.
Nobody even knows for sure what the cause is of most of these failures, it could very well be something mechanical like a misalignment of a gear or something that cause the SDM motor to fail.

There is so much uncertainty that it would be in responsible if Pentax actually enables it.
They might put it inside the debug menu since that breaks your warranty if you do enable it and as such making it your own responsibility.
07-10-2012, 12:21 PM   #22
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QuoteOriginally posted by Docrwm Quote
Perhaps. It's important to note that Lens Rentals does not rent Pentax equipment.
Exactly. While the numbers reported here may be reflected there if they did carry Pentax, they may also have been higher. Nor do those numbers reflect how many were covered by warranty or what the warranty was on the original product.

Regardless, what other manufacturing firm would be allowed to have a product failure rate of 6% and still be in business? Would you buy a car from a company knowing you had a 6% chance it would fail and leave you with bill amounting to a goodly percentage of its cost?
07-10-2012, 01:13 PM   #23
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So you're suggesting not to buy a camera at all or many other products like the computer you're behind... well that is an option.



For car company...
BBC - Open Secrets: MOT failure rates released


I believe most of them are still in business...

So sadly 6% is actually good these days.... often with surveys the ones with the problem often come forward faster so it might be slightly lower but we dont know that for sure.

07-10-2012, 01:35 PM   #24
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QuoteOriginally posted by Tom S. Quote
Exactly. While the numbers reported here may be reflected there if they did carry Pentax, they may also have been higher. Nor do those numbers reflect how many were covered by warranty or what the warranty was on the original product.

Regardless, what other manufacturing firm would be allowed to have a product failure rate of 6% and still be in business? Would you buy a car from a company knowing you had a 6% chance it would fail and leave you with bill amounting to a goodly percentage of its cost?
Consumer electronics are designed to last one to two years. Unfortunately, you can't really have it both ways. Either you pay for a product that lasts (significantly more than current prices) or, you get a product that will need periodic servicing. Professionals expect to do this and therefore have back ups for just about everything -- even high end equipment.

I am not really buying that DC motors are so much better than SDM motors. Maybe they are faster, but there is only one lens out there with such a motor and there are significantly fewer people who own it as compared to those who own SDM lenses. There just is no extrapolation as to comparative failure rates over time.

Truthfully, my biggest problem with SDM is that it is slow. I expect at some point for these lenses to require servicing and I am OK with that, but I just wish they would come out with second versions with faster focus motors...
07-10-2012, 02:13 PM   #25
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QuoteOriginally posted by Rondec Quote
....I am not really buying that DC motors are so much better than SDM motors. Maybe they are faster, but there is only one lens out there with such a motor and there are significantly fewer people who own it as compared to those who own SDM lenses. There just is no extrapolation as to comparative failure rates over time....
Expensive does not mean better, it just means expensive. The two are not directly related.

The sample size is pretty good statistically for the 18-135 with DC at 100 and the 0, yes ZERO, reporting failure is therefore pretty dramatic. The numbers for the 18-135 are just amazingly better than the SDMs. You can claim otherwise but that's just not the case.
07-10-2012, 03:28 PM   #26
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QuoteOriginally posted by Anvh Quote
So you're suggesting not to buy a camera at all or many other products like the computer you're behind... well that is an option.



For car company...
BBC - Open Secrets: MOT failure rates released


I believe most of them are still in business...

So sadly 6% is actually good these days.... often with surveys the ones with the problem often come forward faster so it might be slightly lower but we dont know that for sure.
You are missing the point. Remember, this 6% is a catastrophic failure. Reported auto problems can be something as simple as a loose bolt. Not to mention it's in an item that is a thousand times more complicated than a lens, yet comes with as much as a ten year warranty. In fact on that point, no new car comes with anything less than a three year warranty. My point was if you bought a car and it had a problem that cost 40% of it's value to fix after very little use, it would be totally unacceptable. I suspect your view would be entirely different if it was your lens that went bad, especially if you were living on a fixed income.
07-10-2012, 03:35 PM   #27
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QuoteOriginally posted by Rondec Quote
Consumer electronics are designed to last one to two years. Unfortunately, you can't really have it both ways. Either you pay for a product that lasts (significantly more than current prices) or, you get a product that will need periodic servicing. Professionals expect to do this and therefore have back ups for just about everything -- even high end equipment.
Bull crap. You may equate your statement to consumer's electronics devices that change everyday, like cell phones, but comparing a camera lens to consumer electronics is asinine. Do you really believe your camera was only designed to last 2 years or that any of the lenses were? How about the radio in your car, or even your computer for that matter.
07-10-2012, 03:48 PM   #28
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QuoteOriginally posted by Rondec Quote

It feels to me like the rate of SDM failure has gone down considerably over time (it's just a feeling). I currently own the DA *16-50, 50-135 and 55. The 50-135 I have owned the longest (4 years) and it has had no trouble. The 16-50 I have owned for 3 and 1/2 years and it required SDM replacemnt 5 months after purchase. Since then it has been fine. The 55 I have owned for 2 years and it has had no problems. Of course, this is only anecdotal evidence that things are better and there will be others who share stories about lenses that have required motor replacement multiple times.

I, too, thought that things were better until my three year old DA*16-50 failed recently. Not surprisingly, I have changed my mind about that. Although the SDM failure survey on this site may not be scientific, the percentage of reported failures of the 16-50 is too high to be a matter of adverse selection.

Rob
07-10-2012, 06:13 PM   #29
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QuoteOriginally posted by Tom S. Quote
You are missing the point. Remember, this 6% is a catastrophic failure. Reported auto problems can be something as simple as a loose bolt. Not to mention it's in an item that is a thousand times more complicated than a lens, yet comes with as much as a ten year warranty. In fact on that point, no new car comes with anything less than a three year warranty. My point was if you bought a car and it had a problem that cost 40% of it's value to fix after very little use, it would be totally unacceptable. I suspect your view would be entirely different if it was your lens that went bad, especially if you were living on a fixed income.
uhhh catastrophic failure, like that the lens explode or stop working? we are talking only about AF the rest of the lens is still fine.
Most repairs SDM repairs involve unsrewing the back of the lens where the mount it, it's basically a cover where the electronics are and the SDM.
Not sure how the SDM is held in placed but it's meant to be replaceable so not a big of an deal really.

The report is few hundred pages so there would be data about the kind of failures i assume.

Well that's a warranty problem, something very else you went on about first. And it's not 40% of the value it's 10 to 15% and that's with the man hour, you can actually replace the motor yourself if you want.
Here in my country there is a law about that actually extend the warranty of the product by expected expectations. The DA* range is put forward as a professional lens serries and as such it's expected to be better and more reliable then the consumer product so that the lens stop working after 6 years is unacceptable since there are many cases of SDM failures that makes it a strong case for me. I'm not worried.

Fixed income is much better you know what you get at the moment i don't have that luxury so i need to watchout what i do...
07-10-2012, 06:14 PM   #30
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QuoteOriginally posted by robgo2 Quote
I, too, thought that things were better until my three year old DA*16-50 failed recently. Not surprisingly, I have changed my mind about that. Although the SDM failure survey on this site may not be scientific, the percentage of reported failures of the 16-50 is too high to be a matter of adverse selection.

Rob
I've read someone in the UK a pro fashion shooter send his DA* lenses to french to has his SDM be upgraded. This was 3 years ago i believe.
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