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02-07-2016, 03:32 PM   #16
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QuoteOriginally posted by THoog Quote
The last polls I saw on PF seemed to indicate that SDM failures tapered off around 2011 (coincidentally, Ricoh bought Pentax from Hoya in 2011). Pentax switched to a different internal motor technology ("DC") for most new lenses. The latest lens with the SDM label is the "D FA 24-70 ED SDM WR". It's a Tamron design, so it is unlikely that it is using the same motor technology as the earlier SDM lenses. I'm not sure why Pentax revived the "SDM" designation, when it has such a bad reputation. These days, the biggest complaints about motorized Pentax lenses seems to be focus speed, but RIcoh appears to be working on that area as well.

Unfortunately, the Internet is forever, so those reviews from 2011 will always be around, warning you off Pentax and SDM lenses. An SDM lens may still fail - there are going to be lemons in every batch of lenses, but at this point, it does not appear to be more likely than other types or other brands.
SDM is a screw drive, driven by a small electric motor more like the old screw drive with an internal motor attached. The new DC motors are ring motors a totally different technology. I think it's safe to assume that the Tamron tech in this lens was more suited to SDM than it was to designing a ring drive for the motor. And besides who need lightning fast AF for 24 to 70? That being said, my belief is the original SDM failure were caused by to much variation in barrel tolerances, leading to some lenses being tighter than others, and the original SDM motor being to weak to overcome the resistance that happened when a small ( but within tolerances ) outside barrel got matched with a large (but within tolerances ). I'm sure if there is an SDM motor going into the 24-70 it's more powerful than the original SDM and possibly than the revamped motors that are in lenses like the DA*60-250.

To my mind there is no possibility that Pentax engineers make the mistake of putting an underpowered (in some cases) motor into an SDM lens again.

For people like myself, with my DA* 60-250, there''s nothing wrong with SDM. But it's not a s=fst focusing as my DA 18-135 with it's ring motor.

02-07-2016, 04:08 PM   #17
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Pentax used the SDM trademark for the 24-70 for the same reason they used it for the 18-270...

It's a trademark they already own and they aren't going to use the Tamron USD trademark...
02-07-2016, 04:53 PM   #18
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QuoteOriginally posted by boriscleto Quote
Pentax used the SDM trademark for the 24-70 for the same reason they used it for the 18-270...

It's a trademark they already own and they aren't going to use the Tamron USD trademark...
But rather than reuse something with a negative connotation, couldn't they have come up with something bland and generic, like "HD"?
02-07-2016, 09:27 PM   #19
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FWIW, Eric Hendrickson in his interview said that once he's put a current replacement SDM motor into a repair job, it's been fine.

02-08-2016, 02:12 AM   #20
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QuoteOriginally posted by bertwert Quote
I've seen this clip with different captions about Canon failing with sensors and whatnot...
I would love to see one about sony, considering the overheating problems battery life and the e mount zeiss batis 85mm being inferior to the older cheaper sigma 85mm on other systems

QuoteOriginally posted by THoog Quote
the biggest complaints about motorized Pentax lenses seems to be focus speed, but RIcoh appears to be working on that area as well.
I tried some old non-usm ef lenses on the 70d, man what a huge difference in speed from my old eos 30 film camera, it was almost a 4 fold impovement, so if ricoh manages to workout the quriks in the focusing then it would hopefully benefit all af lenses in the system *wishful thinking*

QuoteOriginally posted by bschriver11 Quote
If one were to troll Canon forums or Nikon forums i'm sure you would have no trouble finding plenty of focusing motor failures.
when i did that i found sigma to be the number one af motor failures, nikon users bitching about no having screw drive, and canon raging about aperture cable problems

QuoteOriginally posted by THoog Quote
couldn't they have come up with something bland and generic, like "HD"?
they could always revive the stupid naming conventions of the past (*ist D, *ist DS ect)
02-08-2016, 02:42 PM - 1 Like   #21
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QuoteOriginally posted by Ratcheteer Quote
they could always revive the stupid naming conventions of the past (*ist D, *ist DS ect)
They are saving that for the full-frame... *ist DF, anyone?

Pentax does have something of an anti-genius for names. Now, if I had been in charge, either the K-7/5/3 sequence would have been reversed, or else "K-50" would have come before "K-30", the "Limiteds" would have been called "Takumars", and the successor to "SMC" would have been "SDMC", with no explanation, and never admitting publicly that it actually stood for "Super Duper Multi Coat".
02-08-2016, 02:43 PM   #22
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QuoteOriginally posted by THoog Quote
Pentax does have something of an anti-genius for names. Now, if I had been in charge, either the K-7/5/3 sequence would have been reversed, or else "K-50" would have come before "K-30", the "Limiteds" would have been called "Takumars", and the successor to "SMC" would have been "SDMC", with no explanation, and never admitting publicly that it actually stood for "Super Duper Multi Coat".
I vote for you in charge.
After me of course...
02-09-2016, 02:00 AM   #23
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QuoteOriginally posted by THoog Quote
They are saving that for the full-frame... *ist DF, anyone?
and the successor to "SMC" would have been "SDMC", with no explanation, and never admitting publicly that it actually stood for "Super Duper Multi Coat".
SDMC
Maybe not so good on second thoughts. People might believe the coating will fall apart after a few years

03-06-2016, 05:47 PM   #24
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QuoteOriginally posted by THoog Quote
But rather than reuse something with a negative connotation, couldn't they have come up with something bland and generic, like "HD"?
See, this is exactly it. They should have kept SMC (maybe make it UMMC - ultra mega multi coating), but changed the SDM. Because SMC was actually a positive thing that Pentax was known for, while SDM was a negative thing. Why get rid of the good and stick to the bad?
Anyway, hope neither causes problems..
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