Pentax SDM to Screwdrive Autofocus Conversion
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- Опубліковано 6 лют 2025
- Hello everyone, this video demonstrates how to complete the SDM to screw drive auto focus conversion for the older Pentax camera lenses!
Here is what you'll need:
(I do not own or maintain these programs; use at your own risk)
PKTether: drive.google.c...
^^^ Link may be dead.
Try blacknight659's github: github.com/bla...
Click on the 'PK_Tether_0_7_0.zip' link and then click on the 'View Raw' link at the bottom to download the files
Debug Files: www.dropbox.co...
^^^ Link may be dead.
Try blacknight659's github: github.com/bla...
Click on the 'enable Debug Menu.zip' link and then click on the 'View Raw' link at the bottom to download the files
Big thanks to blacknight659!
Notepad++: notepad-plus-p...
Pentax I-USB7 USB Cable
List of compatible lenses:
smc PENTAX-DA* 16-50mm f/2.8 ED AL [IF] SDM
smc PENTAX-DA* 50-135mm f/2.8 ED [IF] SDM
smc PENTAX-DA* 200mm f/2.8 ED [IF] SDM
smc PENTAX-DA* 300mm f/4 ED [IF] SDM
Compatible cameras (I think):
K-5 IIS
K-5 II
K-5
K-r
K-20D
Time stamps:
1:12 - Skip background
1:41 - Download PKTether and connect camera to computer
2:24 - Enter camera into debug mode
2:44 - Download debug files
3:21 - Access development menu(4) and extract lens data
4:14 - Make backup of .LNS file
4:43 - Replace C0 with 80, but only in column 03
6:20 - Upload the edited code into the lens
7:00 - Exit debug mode and format SD card
7:21 - UncleVanya Conversion Service: www.pentaxforu...
Send us stuff!
Stephen Foster
PO Box 99900 WU 227 122
RPO Meadowbrook
Edmonton AB T6T 0W4
![How to repair Pentax lens SMC DA* 50-135mm F2.8 ED AL [IF] SDM with focus problem](http://i.ytimg.com/vi/iUqD8FTPpyQ/mqdefault.jpg)
It worked with my 300mm that I bought used some years ago on ebay from Germany and the autofocus worked occassionally. After sitting for ~5-6 more years, the autofocus was dead. This helped a lot, THANKS! :)
Thanks for posting this, got the 50-135 working and reduced the desire to get a mirrorless😆
Phew, that focus ring throwing trick at the beginning just prevented me from sending a newly purchased used 50-135mm back! Thanks!
Thanks for putting this together! I appreciate everyone who figured this out, and those who put guides out before, but this was the most clear one and it was nice to have a newer guide. Converted my DA* 300mm and 50-135mm this evening in no time.
I have a K10D and was unable to use the same method as you, but through some digging provided in the debug files I saw that it was unnecessary to go through all these steps, at least with the K10D. You can trigger debug mode by simply putting a txt file on the SD card with a debug open menu command. From there you can unload the lens ROM, modify it as you show, and load back. It was very simple. Just in case anyone else has an old camera not supported by the other method/can't use pk tether/doesn't have a cable. Those seem unnecessary for some camera models at least. Go to the debug files dropbox link and if your model isn't listed click Other Cameras and read through that info :)
Hey snappiness - did you do it after your 300 failed or as an af speed upgrade?
@@doncoombez My 300 failed twice but recovered after each time, so I knew it was on the way out. AF did feel a little bit faster, but probably just because mine was in process of dying. I don't actually think it's faster than a working SDM version, though people have reported different things.
Now my DA* 16-50/2.8 is brought back to life. Thanks for excellent instructions.
Dude, I had not used my 16-50mm or my 50-135mm DA* lenses for years because of SDM failures. Thanks to this video, I'm back to my best glass again! I can give my primes a rest. Thank YOU for taking the time to share this!
BEFORE committing to do this - try the 1c fix ... it shouldnt work, but it does.
IF your SDM motor is broken, then its broken, and the 1c fix wont do anything. But if its notr eally broken, then this is worth a try.
The 1c fix :
- take the lens off, and use a small flat head screwdriver to action the screw drive. It should rotate cleanly with no resistance, all the way from minimum to infinity and back again
- place a fully charged battery in the camera body
- attach the "broken" SDM lens
- set both the body and the lens to AF
- press the AF button on the body - hold it for a few secs
- press and release the button dozens of times. Keep doing this for a few minutes, dont despair, and dont give up early
- after a while, you will notice that the focus distance is starting to move a tiny bit when you press the AF button on the camera. Keep going !
- after another short while, the entire lens springs back into life, and SDM works again at full speed with no issues.
- Attach the next broken SDM lens, and try again.
- It should take less time with the next lens
It seems like there is some level of capacitance in the camera body and or the lens that needs "recharging" to bring the lens back to life.
I cant see a capacitor on the SDM board (doesnt mean its not there, I just cant see one). But yeah - it definitely works, provided that your lens is actually in good condition.
Thanks very much for this fix. It has worked for me, with my 50-135 and 16-50, my two best lenses. My older camera is a K10 so would have been difficult to work through a fix!
Is your fix long term or do you need to repeat from time to time?
Thank you very very much! You saved my life!!!
@@grinsekotze so it worked ?
Mine have been unused in storage for 8 months - took me 15 mins to get them going again. They still work :)
@@steveoc64My lens lay unused in the drawer for about 2 years. Then the autofocus stopped working. With the K-3, I could still activate it by switching between video and photo mode. After another 6 months in the drawer, that didn't work anymore either. Your tip brought the lens back to life after about 10 minutes. I'm curious how long it will work now. Otherwise, I know now how to revive it. Thank you!
@@steveoc64 My lens lay unused in the drawer for about 2 years. Then the autofocus stopped working. With the K-3, I could still activate it by switching between video and photo mode. After another 6 months in the drawer, that didn't work anymore either. Your tip brought the lens back to life after about 10 minutes. I'm curious how long it will work now. Otherwise, I know now how to revive it. Thank you!
Just performed this on my 50-135 with a K-R. So happy it worked! Thanks!
Wow! You nailed it on this walkthrough man! I tried for hours with a K10D to flash a 16-55 with no luck. Ran across this today and had a 50-135 flashed and ready in about 15 minutes with a K5 II. Major props for helping us find PK_Teatehr again!
Absolutely brilliant video. It makes a change to have someone who explains things calmly and logically, rather than pissing and blundering about all over the place with irrelevant comments and multiple false starts. Had my heart in my mouth for the entire process, and did not in fact encounter a single problem. Thank you.
Thanks for the detailed instruction, I was just bit late to know this trick and updated my K3-1 FW too early to disable this hack, I wished Pentax to release unlocked FW for old models so that we can save those good old lenses with failed SDM.
Tested a lot of cameras downwards and the first that worked was the Pentax K-m.
Also the *ist D series worked great. K-3, K-30, K-50, K-70, k-s1, K-s2, K-20D, K-10D, did not work with the software.
For those you who are having trouble with the Google Drive link for PKTether, below is a link to Justin Hamblins video for debugging; in his video description he has a working (as of time of writing) github link to download the software
ua-cam.com/video/gpfcEebrBSs/v-deo.html
Much thanks to all that figured this one out and put out this invaluable information; I'm in the process of acquiring a used K-5 to in order to resurrect my 50-135/2.8 :)
FOLLOW UP: SUCCESS - 50-135 is alive and well with screw driven focus
I had one hitch; the first time I tried to dump the modified code into back into the lens, I got an error. I doubled checked my modified codes in the word file and tried a second time and it was successful
So helpful you absolute legend! Thanks!
Thank you. I just converted my 50-135
Easy to follow video. Good stuff!
Thanks for this I have managed to get my 50-135 and 16-50 working again, brilliant! Is this a long term fix or is it something you need to do from time to time?
Great Tips... it works for my DA* 50/135 on my K5 and then directly on K3 ( set up on K5) Great Thx! :) ((let the lens you need to fix on the camera...(lol)if not : everything will be code ''ff'' on notepad :)))
Nice! Thanks
This video converts the 50-135, do you make the same changes on other lenses (e.g. CO to 80 in column 3)? I need to convert the 16-50, the 60-250 and the 300.
Thank you for making this video. My son and I fixed both of our 50-135s in about 45 minutes. WOOHOO!
I do not know 100%, but I believe so! I only own the 50-135. However, I believe you should change every 'CO' in column 3 to '80' no matter which lens. Always make backup files in case something goes wrong and you can revert to original settings!
Great vid, I just sent a request through to download pk tether :)
Hello - just letting you know - there is no request needed. The program downloads right away. Might be a computer setting issue on your end?
@@PentaxTips Thanking you, seems the link was broke for me... anyhow got PKtether working and now have a usable 16-50 2.8 that i bought second hand cheap :D
Pentax K7 woks as well for conversion
thank you for great info. Unfortunately I have Pentax K3 ii, and could not convert my 50- 135mm to SD. I live in Calgary, just wondering are you still do this service, or could you accept if I can drive up one day to get my lens converted. Best regards, Johan
We might be able to arrange something. You can email me at PentaxTips@gmail.com and we can talk about options.
buen video gracias
The debug code link is dead.
Oh no! I’ll go looking for a new link and I’ll add it to the description if I find one. If anyone finds one, please let me know!!
I have put a new link the description showing the location of the files to allow the debug menus!
How can i get the develop mod for my K5? The link is disable!
I have put a new link the description showing the location of the files to allow the debug menus!
After installed and opened the PK Tether. I connect K3 to PC by cable, but the PK Tether can not recognize the K3. Therefor I cannot Turn On the DebugMode as the video. I do not know why. Maybe the cable is the reason?
K3 is too new. Needs to be older than a K5. The camera requirement is explained near the beginning.
@@PentaxTips I has just try with K5ii. After got the LENSEEP.LNS, I open with notepad and the content text is not the same as in your instruction. I find C0 and replace with 80 then put back to camera . But Error message .
Work on KP ?
The post-converted lens will work fine on a KP. But you cannot convert the lens in the first place with the KP.
When I click link for pk tether it says file does not exist
apparently this doesn't work on a mac
KP support?
You won't be able to convert the lens with a KP, but once the lens is converted, it will work on every camera in screwdrive including the KP.
hello I can not download pktether it asks me for an access authorization do you know how?
cordially
make sure to use the Google Drive link, do not download from the website (see description)
@@PentaxTips hello I can not download PKTETHER the google link asks me for access to the owner, access I requested but not received a link. If you have a link to recover software please
I just now downloaded the program from the google link as a test, and was not asked for access. The link and download work as expected. I'm going to guess it's an issue on your computer.
@@PentaxTips hello thanks for your quick reply i will test with another computer ..
@@PentaxTips I'm having the same issue =(