[twitch]

The Tokina versions of the 16-50 and 50-135 have screw drive AF.

[borno]

The Tokina versions of the 16-50 and 50-135 have screw drive AF.

That makes sense then, and they probably didn't sell enough of the EF mount versions for a lot of problems to develop. The extra warranty helps too I guess. (EF has no screw drive)

[rvannatta]

I can say that I own or have owned at least a bucket full of Pentax glass dating back to when they were selling m42's. I own at least 4 of the 'big 5' SDM's, the 16-50, the 50-135, and the 60-260 as well as the 200 prime. I do not have the 300 prime for the reason that I own
BOTH the 300 A* primes--- the f/4 one and the f/2.8 model (which take the long converters which I have).

After using and owning multiple pentax lenses for over 40 years I have had exactly 1 lens
fail me.--- It was a Pentax-M 50mm lens which ceased to function properly after I dropped it while attached to a camera lens first on a concrete floor. The inferior designed helical thread broke out of the lens barrel and the lens came apart in 2 pieces and has never worked right since.

If the trolls that never saw a Pentax lens they didn't want to bad mouth want to send me some money, I'll mail the broken pieces of the lens I dropped so they will actually have some evidence that at least one Pentax lens in history broke.

I for one find these hot air threads tiresome.

[Tommot1965]

recently on the Nikon slr lens forum {DPR} one chap was thinking of giving up on all his AFS lenses due to the bad run he'd had with AFS...although his thread was inundated with positive posts of other users experiance with AFS lenses

the Nikon 17-35 F2.8 has a bad rep for AFS failure and that's a $2500 lens!!..Ive just bought a used one..so Ill find out myself to its reliability .

so I do feel that pentax is not alone in lens motor failures..

[JHD]

I'll stick with Sigma's HSM on account of the reported incidents of failure being few and far between despite the fact that these lenses are made in many different mounts for various manufactures, which means in turn there are a lot more reliable HSM lenses than SDM lenses etc out there.

The other big consideration is here in Canada SDM products come with a 2 year warranty. I recently bought a Sigma 50-150 HSM and it came with a 10 year manufactures warranty.

[8540tomg]

Thanks Tommot1965

This is the sort of anecdotal evidence I was looking for. Empirical data would be better but it may not exist. In any case I find it had to believe Pentax is any better, or worse for that matter, than the other lens makers in the area of failures. Any time you have moving parts, as with your car, you will have wear and eventual failure.

Perhaps we need something for cameras and lenses like Lemon Aid for used cars? I guess to some degree our lens review database does this job for Pentax glass. It helps to have a variety of opinions from users of various degrees of skill and experience when make a decision about a lens.

Tom G

recently on the Nikon slr lens forum {DPR} one chap was thinking of giving up on all his AFS lenses due to the bad run he'd had with AFS...although his thread was inundated with positive posts of other users experiance with AFS lenses

the Nikon 17-35 F2.8 has a bad rep for AFS failure and that's a $2500 lens!!..Ive just bought a used one..so Ill find out myself to its reliability .

so I do feel that pentax is not alone in lens motor failures..

[Blue]

I can say that I own or have owned at least a bucket full of Pentax glass dating back to when they were selling m42's. I own at least 4 of the 'big 5' SDM's, the 16-50, the 50-135, and the 60-260 as well as the 200 prime. I do not have the 300 prime for the reason that I own
BOTH the 300 A* primes--- the f/4 one and the f/2.8 model (which take the long converters which I have).

After using and owning multiple pentax lenses for over 40 years I have had exactly 1 lens
fail me.--- It was a Pentax-M 50mm lens which ceased to function properly after I dropped it while attached to a camera lens first on a concrete floor. The inferior designed helical thread broke out of the lens barrel and the lens came apart in 2 pieces and has never worked right since.

If the trolls that never saw a Pentax lens they didn't want to bad mouth want to send me some money, I'll mail the broken pieces of the lens I dropped so they will actually have some evidence that at least one Pentax lens in history broke.

I for one find these hot air threads tiresome.

I think you just called some of the Moderators as well as some of the regular posters including Ben Kanarek trolls because they have had SDM issues. If you research the DA* 16-50 you will find that it started life with other problems as well.

The bottom line is how big of a problem are the SDM failures mainly with the 16-50 and 50-135. They do exist though hand have been posted by PF regulars which is a sub-sample of all Pentax users. There could be more users of high end glass on this board than the general Pentax population but don't think so. There are a couple of other forums with some overlap.

The bottom line is that because I haven't had an sdm failure doesn't mean I am going to pretend they aren't a potential. Lastly, what you proved with your bucket of lenses is that mf lenses and screw drive af lenses are very reliable. I am pretty sure that the guys that get on here and praise the SDM and shout down those that have had problems kind of fade away in the event their SDM fails.