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07-11-2012, 09:47 PM   #61
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QuoteOriginally posted by Anvh Quote
So you're saying that the next lens with DC will also be quicker and 100% reliable?

I'm so surprised how many good and reliable data some can draw by a single lens, it's a miracle.
For fun read a bit more into the 18-135 and you will read it has special rear elements tofocus faster with (sigma use this as well), so it's the lens design doing most of the work on the 18-135, no idea how much influence the DC has in that and even if they can move the bigger and better sealed elements in the DA* lenses.

About the build the DA*16-50 is far more complicated it has SDM, screwdrive, and quickshift, the DA18-135 doesnt have the screw drive.
Are you saying the next lens with SDM will have quicker focus and 100% reliable? Get a life, there are ways to speak so that people are happy to explain further. You should be learning how to 'speak' on forum as if you are talking to someone straight in the face. Have a good day.

07-12-2012, 02:08 PM   #62
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QuoteOriginally posted by Tom S. Quote
Yeah, now you're working to bail out the "pigs" Portugal, Italy, Ireland, Greece and Spain. Good luck with that Euro thing.
It's still doing better then the Dollar

Last edited by Anvh; 07-12-2012 at 02:24 PM.
07-12-2012, 02:19 PM   #63
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QuoteOriginally posted by lightbulb Quote
Are you saying the next lens with SDM will have quicker focus and 100% reliable? Get a life, there are ways to speak so that people are happy to explain further. You should be learning how to 'speak' on forum as if you are talking to someone straight in the face. Have a good day.
And you're giving the right example what that comment?
Practice what you preach, was the saying right?

Anyway this an international forum and every country has his own ways when it comes to communications, i'm not going to change my ways because you don't like it.
You should actually study a bit about communication and you will see why your suggestion won't work
07-12-2012, 02:32 PM   #64
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QuoteOriginally posted by twitch Quote
There is no new type, there is only the "old" type. I know the post you are refering to when Ben thought he'd received better replacement SDM motor in his lens, however he has since realised they weren't better and that replacement SDM has since failed him again. At the time the whole new SDM thing was merely speculation, there was no hard evidence for it and it has since proven to be a false hope.

We still have the same SDM-POS we always had. We can only hope DC (or better) becomes the standard for any new lenses.
Thank you Twitch that's the one indeed.

I wouldn't mind ringtype SDM.

If we look at SDM now i would say they got it reliability to reasonable levels with their recent lenses and primes, surely it's not good yet but at least it's low enough for most that it's less of a concern.
Lets hope they have perfected the way to implement it with the upcoming lenses. I'm really looking out for the new DA* lens if that one comes out good then that might reassure some people?
The SDM imago can use something positive if they want to keep using that.

07-12-2012, 02:55 PM   #65
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QuoteOriginally posted by Anvh Quote
It's still doing better then the Dollar
But for how long? Why have investors been dumping it for the past year? Oh wait, it's that PIIGS thing again. Probably just need some more austerity, huh?
07-15-2012, 01:20 PM   #66
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Check out this post for some fairly concrete conclusions (IMO) about the Pentax SDM failure rates:

Pentax SDM Failure Survey Results - Pentax Camera News & Rumors - PentaxForums.com

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07-15-2012, 04:26 PM   #67
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QuoteOriginally posted by Adam Quote
Check out this post for some fairly concrete conclusions (IMO) about the Pentax SDM failure rates:

Pentax SDM Failure Survey Results - Pentax Camera News & Rumors - PentaxForums.com
Adam,
Thanks for the summary. The contrast between the DC reliability in the 18-135 and the SDM issues is rather stark for me. The three most reliable SDM lenses appear to all be primes while the least reliable are zooms among the SDMs. It looks like a rather pricey roll of the dice with the odds against you if you go with one of the SDM zooms (with the possible exception of the 60-250 - which is not on the list of lenses with links in the summary at the top of that new article BTW).
07-16-2012, 01:50 AM   #68
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QuoteOriginally posted by Adam Quote
Check out this post for some fairly concrete conclusions (IMO) about the Pentax SDM failure rates:
Adam you write "...doesn't seem that newer copies of the lens are failing less than older ones.". However, if you exclude 2012 (which makes sense as there seems to be comparatively little data) then the proportion of good copies vs failures improves over time. So it appears that indeed the failure rate seems to fall over time. Or am I reading the charts incorrectly?

07-16-2012, 04:57 AM   #69
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The data would seem to indicate some improvement in SDM failure rates. This is small comfort for DA*16~50 owners such as myself however. Seems we have a pretty good chance of an SDM failure with this lens at some point. I'm pretty sure a car company wouldn't last too long if their products failed to start 30% of the time. Pentax needs to be doing better in this area. I'm happy to report my copy is still working perfectly but I'm a little nervous every time I snap it on the camera.

Tom G

Last edited by 8540tomg; 07-16-2012 at 05:23 AM. Reason: typo
07-16-2012, 05:14 AM   #70
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QuoteOriginally posted by 8540tomg Quote
The data would seem to indicate some improvement in SDM failure rates. This is small comfort for DA*16~50 owners such as myself however. Seems we have a pretty good chance of an SDM failure with this lens at soem point. I'm pretty sure a car company wouldn't last too long if their products failed to start 30% of the time. Pentax needs to be doing better in this area. I'm happy to report my copy is still working perfectly but I'm a little nervous every time I snap it on the camera.

Tom G
Exactly! Thirty percent failure rates would be unacceptable in any other manufacturing field and result in massive protests. Additionally, as the survey points out, some lenses that do not get the use of the top three worse offenders may be just as bad. In my case, as I noted in an earlier post, my 300mm failed. Looking at the statistics, the failure rate for that lens is around 6%, but it's not a lens people use near as much as the three popular zooms listed with failure rated in the double digits. So in all probability, the problem may be worse than the survey indicates.
07-17-2012, 07:02 AM   #71
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I came back to Pentax from Canon where I was used to quick and quite auto focus so I wanted SDM. I got the 17-70mm and for about a year and half I loved it, but it started having focus problems. It was repaired and it was better than ever and less than one year later more focusing problems. When using it all is great for about 15 - 20 pictures and then it acts like it's focusing and will even beep, but when you press the shutter nothing. This is not something that isn't fun in the middle of a paid shoot. I have two Pentax lenses I like the 55-300mm DAL and a old 55mm f1.8 no SDM's. I like zooms so I can carry less in the field and I used the 17-70 for more because it was so sharp. I've had students with Canon 24-70mm f2.8 "L" lenses and my 17-70 was as good or better. Now it sits and waits to be repaired again and sold. I would buy Pentax primes but no SDM again. Pentax has not come out with anything of Pro Quality in over a year and I don't think they will. I love my K5 and I hope it last awhile. If Pentax won't use up-graded parts what makes you think they'll come out with a FF system. They need a better quality flashes, better focus motors and more lenses ie. 100-400mm, 150-500mm, 10-2?mm and up-grade some current lenses and the K5 so no FF for now just cheap stuff.
07-17-2012, 09:17 AM   #72
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QuoteOriginally posted by Tom S. Quote
Exactly! Thirty percent failure rates would be unacceptable in any other manufacturing field and result in massive protests. Additionally, as the survey points out, some lenses that do not get the use of the top three worse offenders may be just as bad. In my case, as I noted in an earlier post, my 300mm failed. Looking at the statistics, the failure rate for that lens is around 6%, but it's not a lens people use near as much as the three popular zooms listed with failure rated in the double digits. So in all probability, the problem may be worse than the survey indicates.
We are talking about an average here so it doesnt matter how many or few are sold.
07-17-2012, 09:35 AM   #73
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QuoteOriginally posted by Anvh Quote
We are talking about an average here so it doesnt matter how many or few are sold.
Where in my post did I say anything about numbers sold? I'm talking about usage. Most people who buy a 60-250 will use it a lot more than people who buy a 300. My point, which obviously went over your head, was if people used the 200mm and 300mm as much as the various zooms were used, the failure rate would likely been much higher for those lenses. I suspect the double digit failure ratings for the three zooms listed would extrapolate (google it if you don't understand it) to the other SDM lenses if those other lenses received the same amount of usage (not sales) the three zooms with the highest rate of failures received.

I know you are a dyed in the wool fan boy of Pentax, and you refuse to admit there's a problem, but don't let it affect your reading comprehension.
07-17-2012, 09:44 AM   #74
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QuoteOriginally posted by Tom S. Quote
My point, which obviously went over your head, was if people used the 200mm and 300mm as much as the various zooms were used, the failure rate would likely been much higher for those lenses.
This argument may not apply, since many reported SDM failures appear to have followed periods during which the lens was not being used.
07-17-2012, 10:01 AM   #75
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QuoteOriginally posted by lytrytyr Quote
This argument may not apply, since many reported SDM failures appear to have followed periods during which the lens was not being used.
That is a rumor which has not been substantiated. Doesn't it strike you odd that three of Pentax's most popular zooms would exhibit this effect vs lenses that typically are not used as often? Using the logic of use it or lose it, don't you think the 200mm and 300mm would have topped the list for repairs?
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