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View Poll Results: Select the option that best describes your agreement with the statement
I have a dual SDM and screw drive lens and I want the ability to choose the focus mechanism. 20258.38%
I am planning on buying a SDM/screw drive lens and I want the ability to choose the focus mechanism. 6919.94%
I will not buy a SDM lens until I have the ability to choose the focus mechanism. 7521.68%
Voters: 346. You may not vote on this poll

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01-13-2010, 09:59 PM   #181
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QuoteOriginally posted by Russell-Evans Quote
This TC is one of the few that is reported to work with some of the SDM lenses. The lack of a SDM TC is one of the reasons for wanting the firmware to allow the use of the screw driven AF on dual drive lenses.

As for the price, I think I was remembering this post in this tamron-tc-converter-pics thread from long ago.


Thank you
Russell
Ok, that makes sense... I had the Kenko 1.5x which worked with SDM, but not correctly - it tended hunt a lot. My theory is that the focusing system knows how much to turn the lens to get focus nearly right, but since it doesn't know a TC is in the way, it over estimates how much to turn the lens, so focusing becomes a series of overshooting brackets - I have know idea if that is correct... I also don't know if the Tamron TCs did this as well or focus properly. The best TC I ever used with my DA* 300mm was the Pentax-F 1.7x AFTC, which of course works by very different means.

01-14-2010, 12:06 AM   #182
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QuoteOriginally posted by heliphoto Quote
I had the Kenko 1.5x which worked with SDM, but not correctly - it tended hunt a lot.
Ron Brandson on DPR has a number of long lenses and more TCs than Hinman. He posted that the TCs like the Kenko, Tamron, Promaster are working well on the K-X and K-7 with all his SDM lenses. I can't remember if he also said his HSM lenses where included. I know he has the Sigma 150-500mm. This wasn't the case with his K10D and K20D.

So it now appears that information about TCs needs to include camera used with to be accurate.

Thank you
Russell
01-14-2010, 12:32 AM   #183
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Yeah - It seems different people have had different experiences with these TCs. I used the 1.5x Kenko with the K20D and the K-7, and on either it hunted too much to be useful for non-static subjects (and would often fail to lock with static subjects as well - I had to find a hyper-contrasty spot in order to get a lock). With screwdrive lenses it was good though - it worked especially well with the Tamron 70-200 (though I never used it much as I usually carried the 1.7x Pentax as my only TC).

In case anyone stumbles on my comments in a search, I'll mention that I had the Kenko Pz-AF 1.5x TELEPLUS SHQ...
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01-21-2010, 12:50 PM   #184
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Dave Duy Le's SDM firmware petition is doing really well at 382 signatures.

Pentax SDM Firmware Petition

Thank you
Russell

01-21-2010, 01:20 PM   #185
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So, has anything been sent to Pentax yet?
JP
01-21-2010, 03:01 PM   #186
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QuoteOriginally posted by jpzk Quote
So, has anything been sent to Pentax yet?
JP
I don't know about the petition.

Ask here
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/80067-superson...tart-fire.html

Or maybe send a PM
https://www.pentaxforums.com/forums/private.php?do=newpm&u=18305

Thank you
Russell
01-21-2010, 04:07 PM   #187
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QuoteOriginally posted by Russell-Evans Quote
Just did that ... at both places.

Hope this will grow and make Pentax realize that we'd love to have this possibility of using either screw/SDM AF.

JP
01-26-2010, 03:19 PM   #188
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Pentax, fix the firmware and I buy a lens!

It is critical that Pentax addresses this. I have a K10D and the DA* 50-135mm f/2.8 lens, which I love. I'd love to get the DA* 16-50mm f/2.8 and I have the money for it, but there are so many reports of the SDM failing with that lens that I will likely go with a 3rd party lens in order to be safe -- which is really sad, because one of the reasons I most want to get the DA* is it's weather sealing (which the 3rd party brands don't offer).

If Pentax released this ability in a firmware update today, I would order the DA* 16-50 immediately. If they don't do it soon, though, Tamron or Sigma is going to get my money instead, and I will have to make do without the weather sealing. The DA* is also 1-2mm wider at the wide end than either of the 3rd party's offerings, which is also appealing to me.

Since both the camera and the lens support both methods, it seems like this would be an extremely simple switch to add to the firmware and it would provide us Pentaxians with MORE confidence in buying the DA* SDM lenses. It is unfortunate that the newest DA* lenses are SDM-only, since this wouldn't help with those lenses. But at least it would give us the confidence that the two most popular/useful DA* (the 16-50mm and 50-135mm) lenses (at least for wedding/portrait/event photography) will continue to have functional autofocus if the SDM fails (which seems to be quite a common occurrence).

Or perhaps Pentax could just issue a statement saying that SDM failures will be repaired free of charge, even if the lens is over one year old (the ridiculously short warranty Pentax provides on it's high-end lenses). All they have to do is tell me that if the SDM fails they'll get me a free replacement ASAP, and I'll buy the 16-50mm tomorrow!

Whichever is simpler for them works for me (though my preference would be the firmware update, since then I don't have any downtime). If they give me this firmware fix for my K10D, I'll never bother them if the SDM fails. I'm happy to live with the old screwdrive autofocus if the SDM fails, but I don't want to spend good money on a high-end lens that could lose its autofocus capability at any moment.

01-27-2010, 02:50 AM   #189
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QuoteOriginally posted by ManWithCamera Quote
It is critical that Pentax addresses this. I have a K10D
I agree Pentax should address the issue, but I'm also trying to get the most out of what I already own.

With the K10D you do have a fall back position. Only the K10D 1.30 firmware has SDM support. You can, through some changed firmware, roll back to a previous version. You roll back with the changed 1.1 firmware, then you can overwrite the 1.1 firmware with the official 1.1 firmware or update to a later version, 1.20 being the last before SDM support was added.

Not great solution if you plan on replacing the K10D, but hopefully by the time you are ready to replace the body Pentax will have addressed the issue. The other part is that, forewarned about the issue, you can buy an extended warranty with the purchase of the lens so that upgrading the K10D to another camera isn't going to leave you high and dry.

Thank you
Russell
01-30-2010, 06:43 AM   #190
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QuoteOriginally posted by calicojack Quote
The DA* lenses have both SDM & screw drive focus. But the new(ish) DA 17-70 is SDM only. On older non SDM cameras its manual focus only. That also means SDM failure = manual focus only and no firmware upgrade can correct that.
The DA* 55mm f1.4 is SDM only as well.

Looking at my current lens collection I think the option of SDM on/off would be a decent idea.
02-01-2010, 10:17 AM   #191
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QuoteOriginally posted by alohadave Quote
Why would you buy an SDM lens and disable SDM?

The SDM lenses that have screwdrives are transitional. As bodies progress, the screw drives are going to go away and all new lenses will be SDM.
I know this is an early post in the long running thread and has been mentioned, but perhaps it would allow AF with a screw drive TC. Plus, some years out should the SDM go out, the lens can still AF in the screw mode.
02-01-2010, 11:03 PM   #192
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QuoteOriginally posted by simdavid Quote
Screw drive is an auxiliary engine to SDM, why not let it be used if the main engine fails in time of needs? The capability is already there in the lens and body, what is missing is the switch.
+1. If my 16-50mm should fail via SDM, it would be great to have screw drive AF.
02-06-2010, 09:00 AM   #193
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QuoteOriginally posted by Russell-Evans Quote
I agree Pentax should address the issue, but I'm also trying to get the most out of what I already own.

With the K10D you do have a fall back position. Only the K10D 1.30 firmware has SDM support. You can, through some changed firmware, roll back to a previous version. You roll back with the changed 1.1 firmware, then you can overwrite the 1.1 firmware with the official 1.1 firmware or update to a later version, 1.20 being the last before SDM support was added.

Not great solution if you plan on replacing the K10D, but hopefully by the time you are ready to replace the body Pentax will have addressed the issue. The other part is that, forewarned about the issue, you can buy an extended warranty with the purchase of the lens so that upgrading the K10D to another camera isn't going to leave you high and dry.

Thank you
Russell
Hi Russell,
At one time I had both the K20D, and K10D, which I was keeping as a back-up body. I intended to change the firmware on the K10D back to a previous version, just as you describe, so that I could instantly have a camera available in case the SDM failed (not a theoretical proposition, as I have had to send my DA*50-135 in for repair- I was sent a refurbished unit in its place...). I was not able to "roll back the firmware" though. IIRC, I had found a version of K10D firmware 1.20 but when I tried to install it, the camera would only tell me something like "the firmware has already been upgraded", and wouldn't allow any backward change. I'm only into photography as a hobbyist, so since I had no other reason to keep two camera bodies and I couldn't change the firmware back as planned, I sold the K10D. It's a moot point now for me, but maybe others would like to know if changing back to the old firmware is even possible, and if so, how it is done?
Paul
02-06-2010, 09:25 AM   #194
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Firmware downgrade

QuoteOriginally posted by NeverSatisfied Quote
It's a moot point now for me, but maybe others would like to know if changing back to the old firmware is even possible, and if so, how it is done?
Paul
See this.
K10D firmware downgrade: Pentax SLR Talk Forum: Digital Photography Review
02-06-2010, 04:15 PM   #195
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QuoteOriginally posted by NeverSatisfied Quote
I sold the K10D. It's a moot point now for me, but maybe others would like to know if changing back to the old firmware is even possible, and if so, how it is done?
Rolling back requires editing the 1.10 firmware with a hex editor to change the header. A lot of people will find this too complicated so there is a 1.10 firmware on the net that has this done so all that is need is for you to download the changed firmware, install, and then if you wish, install an official 1.10 firmware over the changed 1.10 firmware or update to the 1.20 firmware. The 1.20 firmware being the last firmware before SDM support was added.

Thank you
Russell

Last edited by Russell-Evans; 02-06-2010 at 05:15 PM.
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