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05-16-2016, 09:46 AM   #1
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sdm-screwdrive, Pentax k5, 50-135mm help please

Hello everyone!

Question, hopefully simple. With the help of y'all, I'm attempting to fix a minimally working 50-135mm by switching to the screwdrive motor.

I'm going through the instructions posted on this forum, which led to here: How to deactivate SDM and allow for screw drive autofocus with DA* 50-135mm f/2.8 - Le site des amateurs de PENTAX


I've accessed the debug menu on the k5, but I'm completely at a loss of what's next. How do you export the list of commands available to the sd card, in order to open in notepad and change the required files? What am I missing?

The specific part I'm referring to is here: Put the file in the root of the SD cardPut the card inside the switched Off DSLR.
Press and Hold MENU button and switch on the DSLR.

If everything OK, it will show you all options avaible on Debug mode :
Beware to not change a thing you do not need ( once again, all this are made at your own risk)

Use the pad to go to the line
LENS EEPROM SAVE

Make a saved file of the EEPROM to allow you to reverse the process in cas of troubles

{{STEP 3}}
To modify the EEPROM, you can
-Either access the LENSEEP.LNS file you create by saving the file, I ask you to use Notepad++ Notepad++ Home
-Or go to the line :
LENS EEPROM READ/WRITE
You can change the code line by line


Any help/suggestions are greatly greatly appreciated!





-Side note, the lens was purchased on here from a user. Great price/service/etc, I'll leave a review soon. However, further question. When I put the lens on the k5/k5iis with all autofocus settings to on, the lens motor does silently move attempting to find focus. It continually hunts (going over the appropriate focus zone, and moving on, back and forth forever), just ever so slowly. Is this the sdm failure that everyone refers to? Or does it sound like a different issue?

05-16-2016, 10:54 AM   #2
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Is the camera on AFA or AFC? If yes it might be worth trying AFS? If the lens is actually moving, then it doesn't sound like an SDM failure to me

---------- Post added 05-16-16 at 06:58 PM ----------

If this is your first SDM lens, I'd be wary of assuming it's broken. I made the same mistake when I first owned the 50-135. Does it lock focus and allow you to take a picture? Have you tried changing the focus to centre spot? Sometimes the K-3 can get confused for busy scenes - I'm not sure how the K-5 behaves in this regard
05-16-2016, 11:13 AM   #3
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QuoteOriginally posted by dflorez Quote

The specific part I'm referring to is here: Put the file in the root of the SD cardPut the card inside the switched Off DSLR.
Press and Hold MENU button and switch on the DSLR.

If you're already in debug mode you don't need this step. This is for accessing the debug mode. There is no commands to import, the options will be there if you're in debug mode.

You may want to have a look here, start at post #587(Credit to user Duc-Driver): https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/208353-how-...-2-8-a-40.html

Another "easier" solution would be this (Credit UNcle Vanya):https://www.pentaxforums.com/forums/24-photographic-equipment-sale/311609-sal...nversions.html
05-16-2016, 11:49 AM   #4
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robthebloke - AFC or AFS (k5 doesn't have a AFA mode) yield the same results. Slowly rotating back and forth never locking a target. Regardless of bright/dark/contrast subject, single or all focus points.


K57xr - when I turn the camera on, it says "DEBUG MODE" in the top left. If I hit menu, I can access "test mode" which contains capture/system test, af test, strings disp test, icon test, and debug mode disable. Is there a deeper debug mode I need to access?

I probably should have clarified, this is the part I'm at/stuck on.

"Use the pad to go to the line
LENS EEPROM SAVE"

Is that displayed on the camera menu or will I find it in pktether, or on the sd card?


Thanks y'all again.


EDIT - using the link that led to dropbox folders has helped! New menu opened in camera!


Last edited by dflorez; 05-16-2016 at 12:08 PM.
05-16-2016, 12:08 PM   #5
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QuoteOriginally posted by dflorez Quote
Is there a deeper debug mode I need to access?
Yes, there is. The debug menu is about 5 pages, I think you're only looking at the first one. There should be a "LENS ROM CAMERA=>SD" and vice versa somewhere in the penultimate page.
05-16-2016, 12:44 PM   #6
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Brilliant! Got it working. That link to the drop box with the specific files that need to be on the sd card solved it all!

That is a terrifying process, but this lens is now autofocusing like a champ. Seriously, thank everyone! (Not listing all involved, but for real. Highly appreciate!)
05-20-2016, 08:30 AM   #7
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did you use PK tether? I tired to visit that site, but google says it is infected with malware. Where did you get your installer?

---------- Post added 05-20-16 at 10:36 AM ----------

Also, how do you like this lens now that it is converted. Does it seem to focus faster?
05-22-2016, 09:03 AM   #8
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Blacknight, I did. Step 1 on this site led me to the download (it says for k7, but for the early parts it doesn't matter). How to deactivate SDM and allow for screw drive autofocus with DA* 50-135mm f/2.8 - Le site des amateurs de PENTAX Interesting though, I used two different computers during the lens reprogramming. 1 computer said the same google alert, one didn't. Both using the same internet platform and antivirus.

As for how the conversion is now. I never got to see this lens when the sdm drive was functional, so I can't comment on it's speed vs that. However, I've now used it for 2 weddings. I'm absolutely loving it. Focus hits perfectly, plenty fast for my needs. On a k5iis with center point, I've had no issues hitting focus even in low light. AFS or C, both groovy. I have a zillion other weddings I have to edit before I can really get into the newer ones that I used this lens on, but In my unscientific opinion*, it's super solid. At f4 and almost any focal length, it's on par with my 50mm 1.7 (80's autofocus model) at f2. Kind of blowing my mind a bit.

As for the sound, it doesn't bother me. I think Pentax bodies muffle sound very well (side benefit of weather sealing). The only other lens I have with sdm is a sigma 10-20 which I never ever use... so I'm probably just used to the "jttt jjjttt" screwdrive sound though.



*Disclaimer: I don't, nor have any desire to shoot test charts or graphs. Shots based purely on portraits/landscapes in varying lighting.

05-22-2016, 01:42 PM   #9
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Thank you! I actually figured it out and made a new post with the entire process. I agree, it works great!
05-25-2016, 06:28 AM   #10
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anyone tried the * lens with screw drive autofocus? Really fast now?
05-25-2016, 06:43 AM   #11
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QuoteOriginally posted by yipchunyu Quote
anyone tried the * lens with screw drive autofocus? Really fast now?
Not significantly faster, but it is a little. Mostly, it focuses more confidently.

I made a post where I converted mine here: https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/321757-how-...ive-video.html

In the beginning of the video I spin up the AF with screw drive on my K-5ii. I think this should give you an idea of the speed you should expect. It isn't a "test" but you can watch it rack back and forth.
05-25-2016, 05:26 PM   #12
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QuoteOriginally posted by yipchunyu Quote
anyone tried the * lens with screw drive autofocus? Really fast now?
I have the 50-135 converted to screw drive. I just go in a DA * 200 with sdm working and can tell you that screw drive is faster (the 200 sdm performs about the same as my 50-135 when it did have the sdm working)

Randy
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