How to disable SDM on the lens ?

lotech · 04-22-2014, 03:35 AM

Hi there,

I was overjoyed when I read an article about deactivating the SDM on the lens to enable screw drive focusing, thought I could give my handicapped 16-50 a try, but then disappointed that the process requires a camera flashrom programming, I don't want to alter my new K3, so that I can still use SDM on the same lens at later time. I wonder if masking the lens contact can do the trick as well, any idea ?

Sandy Hancock · 04-22-2014, 03:47 AM

Masking the SDM contacts will just give you a manual focus lens.
Either borrow or buy an older body which allows you to access the debug mode and all will be well. I borrowed a K10D from a mate.

Adam · 04-22-2014, 04:11 AM

Originally posted by lotech

Hi there,

I was overjoyed when I read an article about deactivating the SDM on the lens to enable screw drive focusing, thought I could give my handicapped 16-50 a try, but then disappointed that the process requires a camera flashrom programming, I don't want to alter my new K3, so that I can still use SDM on the same lens at later time. I wonder if masking the lens contact can do the trick as well, any idea ?

See this thread:
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/208353-how-...ml#post2203064

lotech · 04-22-2014, 04:11 AM

Thanks for the reply, I would rather manual focus, no rush no cash for another body, and my lens still half able with the SDM,I dropped it and ruined the motor, the repair cost too much that's why.

**PPPPPP42** · 04-24-2014, 10:47 AM

Someday hopefully Pentax will take the 30 seconds required to add the one line of code to the bodies that would add a menu option to override the body to to screw drive only. It would be simply changing the one line you change in the lens in debug mode only doing it on the camera end.
Easy firmware update, it wouldn't even actually be new code, just a software switch to override the existing lens detection to screw drive only.
The current fix basically just reprograms the lens to lie to the camera and tell it that it doesn't have SDM and is a screw drive lens.

Next time we interview Pentax nag them about it will you?

lotech · 05-19-2014, 03:32 AM

I believe it is worth to add an 'intelligent dual drive mode' in the focusing, which select by system which motor to use, for example, the system first estimate the amount of focus change required, and select whether to use body drive for speed, or/and then SDM for fine tuning/low noise, this can also be override in user settings, and in case you've got a faulty SDM lens the system can still use body focus, so that Pentax/Ricoh don't have to say 'yes, there is some flaw in the SDM design...' how that sounds ?

**clackers** · 05-19-2014, 04:37 AM

But you backup the original lens ROM so that you can shift between SDM and screw drive ...

Much harder to lose two text files in this modern age than two lens caps! :-)

Last edited by clackers; 05-19-2014 at 02:11 PM.

**c.a.m** · 05-19-2014, 11:37 AM

Originally posted by PPPPPP42

Next time we interview Pentax nag them about it will you?

With such a user-selectable feature, Ricoh could promote it as "enhanced operational reliability for those lenses featuring a dual focus drive capability."

Originally posted by lotech

I believe it is worth to add an 'intelligent dual drive mode' in the focusing

Not only enhanced reliability, but Ricoh could also market the feature as a fully intelligent on-the-fly auto focus operation.

- Craig

**lawsonstone** · 05-24-2014, 09:23 AM

Originally posted by lotech

Hi there,

I was overjoyed when I read an article about deactivating the SDM on the lens to enable screw drive focusing, thought I could give my handicapped 16-50 a try, but then disappointed that the process requires a camera flashrom programming, I don't want to alter my new K3, so that I can still use SDM on the same lens at later time. I wonder if masking the lens contact can do the trick as well, any idea ?

You are not modifying the ROM of the camera, but of the lens. So once the lens has been re-programmed, it will work on any camera. The problem with the K3 is we have not yet learned how to put it into debug mode so that we can use it to modify the lens EPROM. But the process posted does not affect the camera's firmware in any way, only the lens. I borrowed a K100D to fix my DA*16-50 and have used it successfully on a K5, K30 and now, my K3.

**clackers** · 05-24-2014, 04:33 PM

Yeah, I used a K-x to do my 50-135 as per the other thread.

Works a treat.

04-22-2014, 03:35 AM	#1
lotech Pentaxian Join Date: Apr 2012 Posts: 1,312	How to disable SDM on the lens ? Hi there, I was overjoyed when I read an article about deactivating the SDM on the lens to enable screw drive focusing, thought I could give my handicapped 16-50 a try, but then disappointed that the process requires a camera flashrom programming, I don't want to alter my new K3, so that I can still use SDM on the same lens at later time. I wonder if masking the lens contact can do the trick as well, any idea ?

04-22-2014, 04:11 AM	#3
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Originally posted by lotech Hi there, I was overjoyed when I read an article about deactivating the SDM on the lens to enable screw drive focusing, thought I could give my handicapped 16-50 a try, but then disappointed that the process requires a camera flashrom programming, I don't want to alter my new K3, so that I can still use SDM on the same lens at later time. I wonder if masking the lens contact can do the trick as well, any idea ? See this thread: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/208353-how-...ml#post2203064 Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

05-19-2014, 11:37 AM	#8
c.a.m Site Supporter Join Date: Jan 2013 Location: Ottawa, Canada Photos: Gallery \| Albums Posts: 4,189	Originally posted by PPPPPP42 Next time we interview Pentax nag them about it will you? With such a user-selectable feature, Ricoh could promote it as "enhanced operational reliability for those lenses featuring a dual focus drive capability." Originally posted by lotech I believe it is worth to add an 'intelligent dual drive mode' in the focusing Not only enhanced reliability, but Ricoh could also market the feature as a fully intelligent on-the-fly auto focus operation. - Craig Last edited by c.a.m; 05-19-2014 at 11:51 AM.

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04-22-2014, 03:47 AM	#2
Sandy Hancock Moderator Site Supporter Join Date: Feb 2012 Location: Adelaide Hills, South Australia Photos: Gallery \| Albums Posts: 11,272	Masking the SDM contacts will just give you a manual focus lens. Either borrow or buy an older body which allows you to access the debug mode and all will be well. I borrowed a K10D from a mate.

04-24-2014, 10:47 AM	#5
PPPPPP42 Site Supporter Join Date: Jan 2012 Location: Wisconsin Photos: Albums Posts: 947	Someday hopefully Pentax will take the 30 seconds required to add the one line of code to the bodies that would add a menu option to override the body to to screw drive only. It would be simply changing the one line you change in the lens in debug mode only doing it on the camera end. Easy firmware update, it wouldn't even actually be new code, just a software switch to override the existing lens detection to screw drive only. The current fix basically just reprograms the lens to lie to the camera and tell it that it doesn't have SDM and is a screw drive lens. Next time we interview Pentax nag them about it will you?

05-19-2014, 03:32 AM	#6
lotech Pentaxian Join Date: Apr 2012 Posts: 1,312 Original Poster	I believe it is worth to add an 'intelligent dual drive mode' in the focusing, which select by system which motor to use, for example, the system first estimate the amount of focus change required, and select whether to use body drive for speed, or/and then SDM for fine tuning/low noise, this can also be override in user settings, and in case you've got a faulty SDM lens the system can still use body focus, so that Pentax/Ricoh don't have to say 'yes, there is some flaw in the SDM design...' how that sounds ?

05-19-2014, 04:37 AM	#7
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	But you backup the original lens ROM so that you can shift between SDM and screw drive ... Much harder to lose two text files in this modern age than two lens caps! :-) Last edited by clackers; 05-19-2014 at 02:11 PM.

05-24-2014, 09:23 AM	#9
lawsonstone Site Supporter Join Date: Oct 2008 Location: Wilmore, KY Posts: 376	Originally posted by lotech Hi there, I was overjoyed when I read an article about deactivating the SDM on the lens to enable screw drive focusing, thought I could give my handicapped 16-50 a try, but then disappointed that the process requires a camera flashrom programming, I don't want to alter my new K3, so that I can still use SDM on the same lens at later time. I wonder if masking the lens contact can do the trick as well, any idea ? You are not modifying the ROM of the camera, but of the lens. So once the lens has been re-programmed, it will work on any camera. The problem with the K3 is we have not yet learned how to put it into debug mode so that we can use it to modify the lens EPROM. But the process posted does not affect the camera's firmware in any way, only the lens. I borrowed a K100D to fix my DA*16-50 and have used it successfully on a K5, K30 and now, my K3.

05-24-2014, 04:33 PM	#10
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Yeah, I used a K-x to do my 50-135 as per the other thread. Works a treat.