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11-08-2011, 12:00 PM   #31
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QuoteOriginally posted by audiobomber Quote
All of the DA* lenses with SDM also have screw drive. The DA 17-70 has SDM but no screw drive. The 17-70 and 18-135mm won't AF on K100D or *istD bodies. It's not such a big deal, there are plenty of lenses that will work. I would recommend a body upgrade for the oldest cameras rather than upgrading from the kit lens to a 17-70 or 18-135mm.
Thanks, I didn't realize the 17-70 was also like that.
We're talking about the same thing, but for different reasons - I'm not worried about the body upgrade (I have a K5 currently) so much as that while bodies may come and go, I'd be quite pissed off if a $$$ lens with SDM only, had SDM failure after a very short warrantee period, with no potential to fall back to screw drive existing. It gets even better if Pentax decides to obsolete some SDM lenses and/or refuses servicing at reasonable rates - I don't feel all that comfortable about assuming an SDM lens with no screw drive backup will still be around in 10 years. If that's the case, then price it accordingly, as a disposable lens. Having a screw drive backup would go a long ways towards convincing me of their long term value even in the event of an SDM or DC failure, while I'm unlikely to spend 1k+ on a lens with a 1 year warrantee that can turn into an expensive MF only lens in a few years or less.

All of the DA* SDM have screw drive, but the screw drive isn't usable on newer bodies if the SDM fails, without a firmware update being made by Pentax. Without that being available, having the screw drive on an SDM lens is of no use with a newer body.

Hope that helps clarify on my point? I'd love to pick up a 50-135 and 60-250 in the future, and potentially other SDM/DC lenses, but with the above kept in mind, I'm unlikely to ever buy more than one until some hope exists of seeing at least 10 years out of one of these lenses. It's ironic that a 10+ year old AF seems to have a better chance of functioning 10 years from now than a brand new $$$ one - there's an easy enough way to correct that, but I'm not sure if it will happen.

11-08-2011, 12:11 PM   #32
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QuoteOriginally posted by rtpguy Quote
All of the DA* SDM have screw drive, but the screw drive isn't usable on newer bodies if the SDM fails, without a firmware update being made by Pentax. Without that being available, having the screw drive on an SDM lens is of no use with a newer body.
There's a lot said about SDM failures, but is it really a problem with lenses other than the 16-50 and 50-135? Some people say the other SDM lenses are as reliable as any makers', and other manufacturers don't include dual drive.

I agree with you though, a choice of SDM or screw on the newer bodies would be nice to have as a backup.
11-08-2011, 12:45 PM   #33
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QuoteOriginally posted by audiobomber Quote
All of the DA* lenses with SDM also have screw drive. The DA 17-70 has SDM but no screw drive. The 17-70 and 18-135mm won't AF on K100D or *istD bodies. It's not such a big deal, there are plenty of lenses that will work. I would recommend a body upgrade for the oldest cameras rather than upgrading from the kit lens to a 17-70 or 18-135mm.
No they don't. The DA*55 is SDM only.

11-08-2011, 01:05 PM   #34
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QuoteOriginally posted by JeffJS Quote
No they don't. The DA*55 is SDM only.

Thanks, I didn't know that. Or maybe I forgot. What was the topic again?

11-08-2011, 05:11 PM   #35
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QuoteOriginally posted by audiobomber Quote
There's a lot said about SDM failures, but is it really a problem with lenses other than the 16-50 and 50-135? Some people say the other SDM lenses are as reliable as any makers', and other manufacturers don't include dual drive.

I agree with you though, a choice of SDM or screw on the newer bodies would be nice to have as a backup.
I don't know - you may well be right, most reports I've seen have been on the 15-50 and the 50-135. So much so, I've contemplated the 60-250 as potentially being in my future. It is some comfort that the 60-250 does have screw drive, if Pentax would make it usable as a user menu option on newer bodies it would probably clinch it for me, but I can't justify the others to myself with the seeming number of reported failures and the short warrantee period.

Now, if the SDM (or a replacement) were priced for what it was, a $20-ish PCB and motor overpriced to $50 or so, and user serviceable...that would also remove my concerns into the realm of 'maintenance' vs 'expensive paperweight potential.' Maybe someone can chime in with a link, but I also recall reading something about one of the SDM lens internals, the motor or other assembly being attached to a plastic mount that can/did break off - which seems poor design, or seriously overpriced planned obsolescence. Paying ~$1k (lens depending) on a 'top of the line lens,' with limited warrantee and a seeming history of problems, and seeing repair bills quoted at several hundred dollars, worrying that the 'plastic mount' may break making it entirely unable to be repaired..yeah, right or wrong, doesn't give me warm fuzzies as a potential customer.

The other manufacturers - well, Sigma Ex lenses seem to offer at least a 4yr US warrantee, and Tamron 6 years.
If you're spending close to a grand or more on something that historically easily lasted 20+ years, competitors with more inexpensive and generally competitive offerings offer more than triple the warrantee..yeah, I'm not thinking a 5 year warrantee is out of line on those lenses, or even 3 + a 2 year $20 extension like you can buy on the bodies.

It's somewhat annoying - there are several ways customer satisfaction/trust could be boosted to improve their reputation and reliability/concerns, but right now it seems most things are the exact opposite. I expect to probably pick up an 18-135 as an overall WR walkaround/travel lens, and a Tamron 28-75 f/2.8 or similar Sigma as the "alternate" - while I'd love for the "alternate" to be WR, for the $, seeming reliability, and the length of time a company will stand behind it via warrantee, there's no other option at this time, for me. I'll "gamble" a bit on the 18-135, but it is at least the newer DC AND it's not a ~$1k+ lens. After that is the bigger decision for me, a nice 70-200 f/2.8 Tamron or sigma EX, or take a chance on a 60-250 SDM at another 50% of the price, which I could spend on a 1.4x teleconverter with the Tamron or Sigma and still be under the cost of the DA*. Because of the SDM reports and warrantee length, I'd likely be considering buying the Sigma or Tamron used without too much worry, but probably only buy the 60-250 or other Pentax SDM lens with the ability to extend the warrantee via SquareTrade or other means. There are definitely days that Pentax makes you wonder what they're thinking..

And yeah, this one sums it up
QuoteOriginally posted by audiobomber:
What was the topic again?


Sorry for the OT. I did in a roundabout way answer the OP, though.
Why not a Tamron 28-75 or Sigma 24-70 + the DA* 60-250 ?
Oops - saw the OP rented them and is now sticking with the 18-135.
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