[peterh337]

A couple of years ago I bought the 17-70 SDM (for a K5).

I read the reviews, which suggested the motor was a bit less than 100% likely to pack up than on the weatherproof alternative of a similar spec (don't recall the type but you know the one) which appeared to have a huge failure rate.

Well, just now the lens has started to get intermittent. After a bit of use it works, but sometimes you have to press the button twice to make it move.

I still have the old 16-45 and that focuses instantly.

Is it definitely the lens and, if so, what is the most cost effective way to get it fixed? There isn't a better quality lens that I can see, of that sort of focal length range.

[EJMzagsfan]

You can read through this. Not sure if anyone knows about the 17-70 though.

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/208353-how-...m-f-2-8-a.html

[sterretje]

Is it definitely the lens and, if so, what is the most cost effective way to get it fixed? There isn't a better quality lens that I can see, of that sort of focal length range.

Just ship it to your local repair center.
You might want to have a look at the Sigma 17-70/2.8-4 Contemporary; I don't know if it's a match for the DA17-70, but it seems quite good.

You can read through this. Not sure if anyone knows about the 17-70 though.

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/208353-how-...m-f-2-8-a.html

That doesn't work; the 17-70 is SDM only.

[EJMzagsfan]

That doesn't work; the 17-70 is SDM only.

That's to bad, good luck anyway Peter.

[jezza323]

Id look at the 17-70 Sigma contempary as mentioned, should be a bit sharper/faster and its not SDM (HSM instead)

[Sandy Hancock]

My own private sample of the DA*16-50 (two copies) has experienced a 100% SDM failure rate. One I had repaired free of charge (despite it being bought second hand from overseas) and sold to a mate in Queensland; as far as I know it's still going strong. The other I converted to screw drive using the instructions linked by by EJMzagsfan in post #2. It continues to be my most used lens, and I'm talking maybe 10,000 shots since conversion....

[Eyewanders]

I've only ever owned a single copy of the 50-135, bought very slightly used back in early March of 2009. It does not see heavy use with me but it's still working just fine.

I'm curious, can anyone here that has had to pay for SDM repair out of pocket (out of warranty) report what the general cost has been???

[Driline]

I've only ever owned a single copy of the 50-135, bought very slightly used back in early March of 2009. It does not see heavy use with me but it's still working just fine.

I'm curious, can anyone here that has had to pay for SDM repair out of pocket (out of warranty) report what the general cost has been???

I've seen reports of $225.

[Canada_Rockies]

My DA* 16-50, bought in 2007, is still going fine. I think the failure rate is somewhat higher than some other lenses, but I don't think it even hit 10%. Those of us who have lenses that don't break don't make big deal threads about them, as I and some others did with the DA* 50-135 when the SDM went South. Mine was 100%. Died three times.

[Rondec]

SDM definitely has a life span. I own four SDM lenses and they are all going fine. The oldest was the 50-135 purchased in 9/2007, so 6 years old now. But, ten years from now, I am sure that everyone of them will have required a new motor. On the other hand, screw driven auto focus lenses have a much longer life span, but people complain about the noise, so I guess you just pick your poison...

[Sandy Hancock]

Conversely, my 55, 50-135 (heavily used for 18 months) and 300 have been fine so far. When the zoom's SDM eventually fails I will not hesitate to convert it to screw drive too - it is such a wonderful lens.

Mind you, my first 55 was dead right out of the box. That went back to the shop pretty quickly.

[cali92rs]

My 16-50mm I bought used...it died on me in a few weeks. But i knew I was going to disable the SDM on it anyway, i bought a cheapo K100D just for this purpose.
I feel like buying a DA 50-135mm now to get more of a return on my investment, lol (thats LBA for ya).

[peterh337]

What would be the best image quality lens in the 17-70 sort of range, for a K3? Doesn't have to be Pentax of course, but I don't want to cripple the functionality in the way it usually happens with flashguns.

[jezza323]

Not many options in 17-70

17-50 opens up to constant f2.8 lenses, Sigma 17-50mm, Tamron 17-50mm & Pentax 16-50mm, should all be a bit better overall than any of the 17-70mms

Of the 17-70mm options I'd go with the Sigma contempary, just based off my own research, not off personal experience (as i don't have any of them)

[normhead]

What would be the best image quality lens in the 17-70 sort of range, for a K3? Doesn't have to be Pentax of course, but I don't want to cripple the functionality in the way it usually happens with flashguns.

I'd get the 17-70 repaired. Apparently the newer SDM lenses have a better motor.