[twitch]

Here's some data from Lensrentals on failures rates of the lenses they carry. Two sigma lenses fill the top 2 places and both for AF motor failure.

Lenses with failure rates 50% or more above average (8.25%)
Lens---------------------------Repair Rate--------Typical Problems
#1 Sigma 50-500 OS------------40%------------AF system, OS system
#2 Sigma 120-300 OS-----------26%-----------Autofocus system, OS system

Full article is here

[Adam]

You can't rely on data from lens rental companies (imo) because people always abuse stuff that doesn't belong to them.

I'm sure that if one were to contact each manufacturer, however, that warranty repair data could be obtained, at least at a very high level.

[areidjr]

...but on the other hand, you don't see reports of failed HSM...

I had a failed HSM on my 70-200 and I know of other similar reports. All in-lens motors fail. Maybe the Pentax SDM was a little more prone to failure, but, since no manufacturer that I know of publishes failure rates we will never know for sure.

[twitch]

You can't rely on data from lens rental companies (imo) because people always abuse stuff that doesn't belong to them.

I'm sure that if one were to contact each manufacturer, however, that warranty repair data could be obtained, at least at a very high level.

True, a year in rental is probably like dog years 7:1. Although the absolute figures are probably too high, the relative positions are probably a decent guide still.

God help us if they ever start renting out Pentax SDM lenses, lol.

[philbaum]

You can't rely on data from lens rental companies (imo) because people always abuse stuff that doesn't belong to them.

I'm sure that if one were to contact each manufacturer, however, that warranty repair data could be obtained, at least at a very high level.

I mistakenly assume LensPlay was a rental company - they are not. It appears to be a website devoted to discussing and selling lenses, etc. They polled some 4300 DSLR owners on LENSES THOSE INDIVIDUALS OWNED, and got the resulting information. I assume they queried their customers on the lenses they had owned previously.

I doubt that repair information can be obtained from lens manufacturers unless its a legal requirement in that country. I know that when the SDM issue was very active, that several from Pentax forums contacted various Pentax technical and sales reps and several denied that it was a known problem. Manufacturers are often reluctant to release information that can be used against them.

[monochrome]

people always abuse stuff that doesn't belong to them.

Exactly. When's the last time you washed a rented car?

[jimr-pdx]

200mm @ f6.3? Yuck

I owned both, and the Sigma made it to 170-180mm at f/5.6 before taking that last step into darkness. The Tamron did it more like 120mm - so consider the Sigma (mark I) a faster 18-170. And my copies of the Sigma (three counting my Sony days) did not creep!

This new model will be interesting to hear about. So many Sigmas have been refreshed with HSM and OS but reviews generally show a slight IQ drop with the tech updates. For myself, I await the Pentax DA offering later this year. I'm perfectly happy stopping at 200mm for this type of lens, it saves weight & bulk and I dislike both.

Edit - a Two Hundred Gram weight gain over the mark I? Wow - 600g vs 405, now That's a real 'yuck'. At least the Mark I will be cheaper if the DA isn't for me.

[RXrenesis8]

You can't rely on data from lens rental companies (imo) because people always abuse stuff that doesn't belong to them.

They would also be abusing the Canon and Nikon lenses then, correct?

They make several disclaimers, including:

This list is not a comment about how good a lens is, it’s about how often it breaks under harsh conditions. Some of my favorite lenses are on this list.

I like being able to use my 16-50 under harsh conditions. It's the reason I bought it!

Just trying to say: the data (and of course, the surrounding and informative explanation) is very helpful to me

[thibs]

One way to look at it is this: if Pentax's new DC AF system in the 18-135mm doesn't fail, why is the original SDM system so prone to failure? You're right that there haven't been any studies on this, but on the other hand, you don't see reports of failed HSM, and in the consumer world, that's what matters. Even if you do a web search for "Sigma HSM Failure Rate" you don't get anything on the topic.

SDM failures happened often with 16-50 and 50-135. No other lenses. Stop this non sense.:cry:

[Adam]

The 17-70mm also seems to be plagued:
SDM Reliability Survey Results - PentaxForums.com

[philbaum]

The 17-70mm also seems to be plagued:
SDM Reliability Survey Results - PentaxForums.com

From your poll on the 17-70 sdm:
2310: 12 failures
2311: 4 failures
2312: 2 failures (normalized to 12 months, that would equate to 5 failures)

Interestingly enough, regards the failures on the 16-50: the high point was in 2009, and then in 2010 the failure rate started falling.

Those failure numbers wouldn't have fallen like that across the board unless Pentax had taken some action to fix the problem.

[thibs]

Those failure numbers wouldn't have fallen like that across the board unless Pentax had taken some action to fix the problem.

But people like to bash SDM, it's trendy.

[Rupert]

Adam - just search for Sigma lens failures: Here's some samples

1. Flickr: Discussing The autofocus doesnt work in SIGMA APO 70-200mm f 2.8 EX DG HSM (Macro) (there's 14 complaints altogether on this flickr page regarding Sigma HSM failing, just 2 samples below)

Man from the North says:
Sorry to hear that hector. You need to return the lens to the dealer, if it is brand new, demand to get a new lens or your money back.

Same thing happened to me, the autofocus stopped working in my 70-200, just like that. Later on I heard that this seems to be a common problem with Sigmas HSM lenses.

Well, I returned my two year old lens to the camera dealer, and he sent it to a Sigma repair shop. One and a half week later I got it back with a new HSM motor in it, and it is working great. I still had warranty on my lens, so it did not cost me anything

Still, I think it´s pretty bad that the lens just gave up like that, I have not dropped it and I handle all my photo equipment with care.

To add to the misery, I was on a photo trip one thousand kilometers from home when the lens decided to quit on me. :/

kenkyee says:
Could you guys list the first few digits of the serial# when this happens?

I thought Sigma resolved this and it was an issue w/ the early release of this lens (failure was due to HSM rollers sticking)...

2. Flickr: Discussing total lens failure update 3/29/2011 in Sigma 18 ...
Mar 29, 2011 ... Is this lens good for Portrait? ... total lens failure update 3/29/2011 ... I hoped it would qualify for repair/replacement under Sigma's recent ...(included replacement of the hypersonic motor)

3. SLRGEAR.COM

Sigma 50-150mm f/2.8 II EX DC HSM APO review by RogerB Review Date: 5/10/2009 Would you recommend the product? No | Total Spent: $700.00| Rating: 3
Pros: sharp lens, good contrast Cons: Poor quality control - lens keeps breaking down
My copy of this lens (in Canon fit) was let down by a consistent failure of the autofocus motor in the lens. I had to send it back to Sigma twice to be fixed. And I do not use the lens much. They did fix the lens quickly, but I do not expect 2 failures in such an expensive product.
Buyer beware!

4. This from: LensPlay - Lens defects They did a survey of various lens owners.

Sigma lenses - 3214 with 725 defects
The probability of getting a good lens is 77 %
The probability of getting 5 good Sigma lenses in a row is 28 %

Pentax lenses - 1753 with 112 defects
The probability of getting a good lens is 94 %
The probability of getting 5 good Pentax lenses in a row is 72 %
======================================================================================

Conclusion:
I think we should enjoy discussing Sigma's new lens without the need to make a derogatory remark in the News comment about SDM focus motors. Without looking very hard, i found the above 16 examples of HSM problems and hadn't expected the survey information from the Lens Rental pages. I'm just saying, Pentax has apparently made some changes to how they assemble the sdm motors and i'm not seeing the number of complaints regarding them, that used to be reported. These lenses and cameras are such complicated mechanisms, that any of them work is amazing. :-)

I'll put my hard hat on :-)

Never had any problem with any of my Sigma lenses...but have had my DA*50-135 fail at SDM twice, and known many others with the same fate. I have a four year Sigma warranty, a six year with Tamron...with the much better reliability of the Pentax lenses you described, where is the Pentax belief in their product?
Anything can fail, but the SDM problem is undeniable by any reasonable standard....in particular if you are a victim. Give us a decent warranty and we will go away and you can put away your hard hat! Until then, I will have to go Sigma/Tamron and save a bundle while doing it!

Regards!

[thibs]

Give us a decent warranty and we will go away and you can put away your hard hat! Until then, I will have to go Sigma/Tamron and save a bundle while doing it!

Agreed. I think SDM has a worse reputation it deserves but this is exactly the reason why Pentax should up warranty.
In EU we are fortunate to have a 2 years legal warranty. This is good. Pentax offering more would be better. Pentax offering 4+ years, especially in the US where prices went up would be smart.

[Chaos_Realm]

I don't understand why pentax doesn't just scrap SDM, and use DC. It's only drawback is noise... Edit: actually just found out its quiet too. Hmmm