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01-21-2011, 05:56 AM   #136
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SDM shouldn't mean "SOL Drive Motor"

Don't get mad at each other people (even as I'm suppressing some anger at some specious reasoning on the part of ... one side or the other of the divide here).

It seems to me even the "it's just a few bad apples (lenses) and noisy complainers" camp might bring themselves to agree that the corporation needs to communicate about the issue, and in any event --

Why the hell does it have to be do or die with the SDM focusing anyway??? The lenses are physically (correct me if I'm wrong) capable of being screw-driven by the body, but current cameras' firmware doesn't support switching from SDM to screw -- wouldn't a simple freakin' firmware patch that would permit users to avoid having to decide among just using manual focus or waiting on repairs (more than once) and going broke in the process or selling the thing (to whom, one wonders) ameliorate the situation considerably?

If SDM were simply a desirable (when it works) fancy feature that one could ignore if necessary while still having an AF lens, then I wouldn't hesitate to buy one. There would be no manufacturing cost at all with a firmware patch, and the company could simply present it as an extra feature -- for all I know, screw-drive might be faster. The user could have a choice between slow but silent, and faster but typically noisy. Thoughts? I have no experience with SDM so people have mercy with my naivete, please

01-21-2011, 03:34 PM   #137
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Most current SDM lenses also have a screw-drive interface. Exceptions are the DA 17-70mm, DA 18-135mm and DA* 55mm. And yes, it's beyond retarded that we can't resort to this mechanism when the SDM motor dies. From reports on this forum, in most cases, the screw-drive focusing is slightly slower than the SDM focusing with the same lens being used on the same camera body (testing conducted on older bodies that can downgrade the firmware to disable SDM support). But I'd happily put up with slightly slower auto-focus speed if it meant the damn lens ACTUALLY WORKED!!!
01-21-2011, 03:38 PM   #138
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QuoteOriginally posted by Hound Tooth Quote
Most current SDM lenses also have a screw-drive interface. Exceptions are the DA 17-70mm, DA 18-135mm and DA* 55mm. And yes, it's beyond retarded that we can't resort to this mechanism when the SDM motor dies. From reports on this forum, in most cases, the screw-drive focusing is slightly slower than the SDM focusing with the same lens being used on the same camera body (testing conducted on older bodies that can downgrade the firmware to disable SDM support). But I'd happily put up with slightly slower auto-focus speed if it meant the damn lens ACTUALLY WORKED!!!
I 100% agree with you that if the SDM motor fails, there is no good reason why the user shouldn't be able to use the screw drive if the lens has both. It would be an easy firmware update Pentax could release; but as they haven't done so by now, I am not holding my breath
01-21-2011, 03:39 PM   #139
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QuoteOriginally posted by dgaies Quote
I 100% agree with you that if the SDM motor fails, there is no good reason why the user shouldn't be able to use the screw drive if the lens has both. It would be an easy firmware update Pentax could release; but as they haven't done so by now, I am not holding my breath
Noisy AF gives pentax a bad reputation... it's better to force you to fix the sdm!

01-21-2011, 03:43 PM   #140
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QuoteOriginally posted by sewebster Quote
Noisy AF gives pentax a bad reputation... it's better to force you to fix the sdm!
I'm sure that was one of many reasons they came up with when they decided not to allow the use of the secondary screw drive system on DA* lenses in the event of a motor failure
01-21-2011, 03:55 PM   #141
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QuoteOriginally posted by Hound Tooth Quote
Most current SDM lenses also have a screw-drive interface. Exceptions are the DA 17-70mm, DA 18-135mm and DA* 55mm. And yes, it's beyond retarded that we can't resort to this mechanism when the SDM motor dies. From reports on this forum, in most cases, the screw-drive focusing is slightly slower than the SDM focusing with the same lens being used on the same camera body (testing conducted on older bodies that can downgrade the firmware to disable SDM support). But I'd happily put up with slightly slower auto-focus speed if it meant the damn lens ACTUALLY WORKED!!!
The need to put both a screw drive mechanism into these lenses likely made them much more likely to break. It is an unfortunate consequence of having a lot of bodies out there at the time that they were designed, that were unable to use SDM. At the same time, newer lenses that don't have both options seem much less likely to break down.

As far as I know, SDM is no faster than the screw drive, just quieter.

At this point, I wish they would ditch the old lens style and up date it to something similar that wouldn't break as often. Sure it wouldn't work on pre-K10D bodies, but there are a lot of other options for those folks anyway. Just call it DA * 16-50 MK II.
01-21-2011, 04:08 PM   #142
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QuoteOriginally posted by sewebster Quote
Noisy AF gives pentax a bad reputation... it's better to force you to fix the sdm!
Are you serious? I've never heard anyone say they don't like Pentax because their focusing system is noisy! I don't care how loud it is as long as it works properly and accurately. What gives Pentax a bad reputation is failing focusing systems, not the noise!!!
01-21-2011, 04:54 PM   #143
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QuoteOriginally posted by builttospill Quote
Are you serious? I've never heard anyone say they don't like Pentax because their focusing system is noisy! I don't care how loud it is as long as it works properly and accurately. What gives Pentax a bad reputation is failing focusing systems, not the noise!!!
I am 99% sure he was being facetious.

01-21-2011, 05:08 PM   #144
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The smiley was meant to indicate my sarcasm. If in doubt you can always assume what I write is in jest somehow
01-21-2011, 07:39 PM   #145
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QuoteOriginally posted by sewebster Quote
The smiley was meant to indicate my sarcasm. If in doubt you can always assume what I write is in jest somehow
Crap, now I'm confused. You added a smiley to that line. Does that mean you're being sarcastic about being sarcastic?

Last edited by Hound Tooth; 01-21-2011 at 11:07 PM.
01-21-2011, 07:45 PM   #146
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QuoteOriginally posted by Rondec Quote
As far as I know, SDM is no faster than the screw drive, just quieter.
Like I pointed out above, the fact that SDM is faster than screw-drive on the same lens has been tested true already. There have been tests conducted on the exact same camera body. It's documented elsewhere on this forum. A 50-135mm lens auto-focuses faster using its SDM motor than using the screw-drive when used on the same body. Mind you, these tests can only be done on K10D's, and my understanding is that the camera's screw-drive motor has gotten faster over subsequent generations.

The screw-drive auto-focus on SDM lenses actually IS really loud. Louder than most screw-drive-only lenses. I've heard a 50-135mm auto-focusing using the screw-drive, and it's a noisy beast. But at least it works reliably.
01-21-2011, 08:42 PM   #147
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if one would disable SDM support, it doesn't make sense to pay for what they are worth right now. considering that other camera lens manufacturers had already come up with better lenses, other than WR, the DA* zooms have outlived their best years in terms of optical performance. SDM is clearly inferior to HSM in terms of performance and reliability. the pricing alone kills the DA* zooms. almost half the price of the Tamron/Sigma counterparts. there is no other reason to buy the 2 Pentax DA* zooms other than being a Pentax brand WR lens.

if ever Pentax would come up with something better in terms of optical performance and silent motor reliability, that would only be the logical time that someone would pay for a $900 and up lens.

personally, I won't even dare to touch or buy either existing 2 DA* zooms for $600. I'd rather spend that money on the Sigma.
01-21-2011, 10:02 PM   #148
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QuoteOriginally posted by Pentaxor Quote
if one would disable SDM support, it doesn't make sense to pay for what they are worth right now. considering that other camera lens manufacturers had already come up with better lenses, other than WR, the DA* zooms have outlived their best years in terms of optical performance.
While I mostly agree with your opinion, I'm curious to know which competitiors' lenses are optically superior to the 50-135mm and 60-250mm and cost significantly less (while ignoring the WR advantage). My understanding is that the 50-135mm has no peer (although the Sigma 50-150mm comes very close... and costs about the same). And there's really nothing to compare the 60-250mm to.

As for the rest, you're right, they've all been outclassed and outpriced for a long time (again, ignoring WR).

edit: oops, the Sigma 50-150mm is discontinued, so that one's not even a consideration

Last edited by Hound Tooth; 01-21-2011 at 10:10 PM.
01-21-2011, 10:57 PM   #149
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QuoteOriginally posted by sewebster Quote
The smiley was meant to indicate my sarcasm. If in doubt you can always assume what I write is in jest somehow
I'm sorry. I was posting from my cell phone and missed the smiley. Oh well, I'll feel like an idiot for a few more minutes and then get over it.
01-21-2011, 11:12 PM   #150
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QuoteOriginally posted by Hound Tooth Quote
As for the rest, you're right, they've all been outclassed and outpriced for a long time (again, ignoring WR).
Aren't the 300mm F4 of the big two companies pretty old and physically larger compared to the DA* 300mm F4 SDM? I'm really happy with mine so far. I don't know how they compare optically, but the Canon one is slightly more expensive and the the Nikon one is a lot more.
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