[alfa75ts]

Any comments would be appreciated

First off I would extract LENSEEP.LNS again just in case.

Perhaps Matt could upload (attach) his unmodified LENSEEP.LNS as LENSEEP.TXT for you to compare. No, don't use his in your lens, there are almost certainly lens calibrations embedded in it.

[UncleVanya]

If you posted your unmodified file, we could look at it and give feedback. I have dozens upon dozens of them.

[ianc]

If you posted your unmodified file, we could look at it and give feedback. I have dozens upon dozens of them.

Thank you - that would be appreciated. .txt version attached

[UncleVanya]

Thank you - that would be appreciated. .txt version attached

My first thought is that someone put 00 in where 80 or C0 was. I will check my files later.

[delboy65]

Before I try attempting this I wanted to check whether the symptoms I am experiencing merit this, or a return to the Pentax UK Service company...

For some time I have noted the AF performance of my 50-135 deteriorating, so much so that now it will only budge if I insert a fully charged battery in my K-3 (even then it is REALLY sluggish)

As this is only a firmware change, I wonder if the fault I am experiencing is mechanical therefore needs a return for service rather than this fix...?

[sebberry]

Before I try attempting this I wanted to check whether the symptoms I am experiencing merit this, or a return to the Pentax UK Service company...

For some time I have noted the AF performance of my 50-135 deteriorating, so much so that now it will only budge if I insert a fully charged battery in my K-3 (even then it is REALLY sluggish)

As this is only a firmware change, I wonder if the fault I am experiencing is mechanical therefore needs a return for service rather than this fix...?

The failure you're describing seems consistent with the traditional SDM failure. The SDM motor failure happens independently of the screw-drive focus mechanism.

If the lens is under warranty, return it for service. If not, the firmware 'hack' outlined in this thread will* convert the lens to the screw drive.

Note that the screw drive is louder, so if you're shooting where you want the quiet operation of the SDM, then return the lens for repair.

*there's always a chance the firmware fix will fail. Make sure you back up the firmware files, preferably keeping more than one backup in case you need to revert to it. If you're not comfortable with the steps, don't try this. A botched firmware hack or flash can permanently damage the lens.

[UncleVanya]

Before I try attempting this I wanted to check whether the symptoms I am experiencing merit this, or a return to the Pentax UK Service company...

For some time I have noted the AF performance of my 50-135 deteriorating, so much so that now it will only budge if I insert a fully charged battery in my K-3 (even then it is REALLY sluggish)

As this is only a firmware change, I wonder if the fault I am experiencing is mechanical therefore needs a return for service rather than this fix...?

It sounds very much like a failing SDM motor. If manual focus works without increased resistance I would guess it will convert. The sdm and screw drive systems are mostly independent focus solutions. If you decide to convert it and it doesn’t work the changes are easily reverted.
If you don’t want to convert it yourself feel free to contact me. I offer conversion services.

[delboy65]

It sounds very much like a failing SDM motor. If manual focus works without increased resistance I would guess it will convert. The sdm and screw drive systems are mostly independent focus solutions. If you decide to convert it and it doesn’t work the changes are easily reverted.
If you don’t want to convert it yourself feel free to contact me. I offer conversion services.

The lens is long out of date in terms of warranty, and having had the previous 55-300mm (now have the PLM) I doubt the increased noise of the screw mechanism vs SDM will be an issue for me..

however I am in the UK and you are in the USofA (probably cheaper I send for SDM repair here than ship to/from the US)

Though tempted to try to firmware update - but short of scrolling through all 18 pages [have read a few] there seems some mis-information (e.g. posts saying "My first thought is that someone put 00 in where 80 or C0 was"

Whilst i am not a geek, I do feel i am quite computer literate - especially if there is a step-by-step process to follow

[mtkeller]

It’s honestly a pretty straightforward process, if you have an older body lying around (or can borrow one or buy one cheaply) that will get you into debug mode. I have lots of geeky skills, but I enlisted zero of them to do this change. As long as you make a backup of the file you transfer from the lens, you can undo things.

[UncleVanya]

however I am in the UK and you are in the USofA (probably cheaper I send for SDM repair here than ship to/from the US)

I agree.

Though tempted to try to firmware update - but short of scrolling through all 18 pages [have read a few] there seems some mis-information (e.g. posts saying "My first thought is that someone put 00 in where 80 or C0 was"

Do you mean firmware update? That’s normally not done for sdm to screwdrive conversion. I guess you could call it a lens firmware modification/hack.

You do realize that I wrote that that in response to a specific lens file? The file was posted by another user and it is consistent with my expert opinion. This is not “misinformation” and I’m a bit offended that you label it as such. But it is possible we have a miscommunication here and I’m giving you the benefit of the doubt.

Whilst i am not a geek, I do feel i am quite computer literate - especially if there is a step-by-step process to follow

The step by step processes varies depending on:

1) Which body you plan to use.
2) how you plan to get the body into debug mode.
3) what you plan to use to edit the files.

If you supply answers to these questions or pose more questions to determine how to decide on answers, you may get the answers that you need to proceed. I apologize if you already have done so the thread is one of many I am participating in and I may have forgotten your details.

Best of luck.

[delboy65]

I agree.



Do you mean firmware update? That’s normally not done for sdm to screwdrive conversion. I guess you could call it a lens firmware modification/hack.

You do realize that I wrote that that in response to a specific lens file? The file was posted by another user and it is consistent with my expert opinion. This is not “misinformation” and I’m a bit offended that you label it as such. But it is possible we have a miscommunication here and I’m giving you the benefit of the doubt.



The step by step processes varies depending on:

1) Which body you plan to use.
2) how you plan to get the body into debug mode.
3) what you plan to use to edit the files.

If you supply answers to these questions or pose more questions to determine how to decide on answers, you may get the answers that you need to proceed. I apologize if you already have done so the thread is one of many I am participating in and I may have forgotten your details.

Best of luck.

Dear Uncle V ;-)
Apologies if my earlier post implied 'mis-information' from yourself, it was meant about trying to follow a long thread
As for the 3 questions you posed above...
- and this is where I am getting a tad worried
RE 1) is the 'hack' limited to a single camera body, or once done can be used on multiple bodies?
RE 1) of my 4 current bodies I could put up a legacy K-3(Mk 1), but ultimately I would want to use on either of my K-3(1)'s, my Katie or my KP
RE 2) not sure I understand the question :-(
RE 4) I assume my Dell laptop.......?

thanks

[UncleVanya]

Dear Uncle V ;-)
Apologies if my earlier post implied 'mis-information' from yourself, it was meant about trying to follow a long thread
As for the 3 questions you posed above...

No worries. I wondered if it was something like that.

- and this is where I am getting a tad worried
RE 1) is the 'hack' limited to a single camera body, or once done can be used on multiple bodies?
RE 1) of my 4 current bodies I could put up a legacy K-3(Mk 1), but ultimately I would want to use on either of my K-3(1)'s, my Katie or my KP
RE 2) not sure I understand the question :-(
RE 4) I assume my Dell laptop.......?

thanks

Re: conversion is lens specific and affects all known sdm/screwdrive bodies made by Pentax to date. Bodies without sdm continue to work as they always did. You are reprogramming the lens to claim it lacks sdm and has screwdrive. Only works on DA* 16-50, 50-135, 200, 300. Does not work on the da* 60-250 or any other lens.

Re: what body will be used to convert with. Not sure what a Katie is. K-3 is too new. K-5 works. K-50 doesn’t. Not sure but I think k30 doesn’t.

Re: debug required along with a body that supports reading and writing lens rom files. Some newer bodies look like they should work as far as menu options but the menu item doesn’t do what it should. Debug mode can be entered different ways on different compatible bodies. My favorite body to use is the k100d which lacks sdm so the lens can be tested in screw drive before investing time in editing the file. Debug mode is a simple boot up keypress sequence.

Re: laptop, windows 10? Get notepad ++ installed.

[delboy65]

Thank you

[FozzFoster]

I made a PentaxTips version:

Youtu.be

Youtu.be

Thanks to this forum for all the help and information on how to complete this process!
Especially @UncleVanya for all his gracious help with all us forum members!

[UncleVanya]

Especially @UncleVanya for all his gracious help with all us forum members!

I’m just a guy with a computer and a little knowledge learned from others who put in the hard work to figure out the way this works. Basically, I can follow directions!