[UncleVanya]

No idea to be honest. It just didn't work for me as far as I remember. I'll be trying again with a 50-135 I've bought recently. I'll test out both SDM and Screwdrive functions with it as it has a sluggish motor. Nice and cheap tho!

Look over what I wrote and make sure you are in the lens rom section of the menus and not the general rom section. Also make sure you are using STORE and LOAD correctly - they are semantically difficult to tell apart in some ways and they are easy to mix up.

[jcdog2006]

I subscribed this thread years ago and wished I'd never need to come back to read all of the posts in here to figure out what is going on............

Well, my DA1650 finally went to the west weeks ago and I came back to this thread this morning to get help. After going through almost all of the posts, I found myself fortunate enough to have an old K100D in the drawer.

Before writing the modified .LNS file back to the lens, I accidentally turned K100D into normal operation mode to find DA1650 was working well with noisy focusing action when I pressed the shutter half way down. (According to UncleVanya, K100D has screw-drive mode only.)

This thread is so valuable, thanks to PF and all of the members who contributed to this thread.

Merry Christmas and happy year 2017 to everyone.

[UncleVanya]

I subscribed this thread years ago and wished I'd never need to come back to read all of the posts in here to figure out what is going on............

Well, my DA1650 finally went to the west weeks ago and I came back to this thread this morning to get help. After going through almost all of the posts, I found myself fortunate enough to have an old K100D in the drawer.

Before writing the modified .LNS file back to the lens, I accidentally turned K100D into normal operation mode to find DA1650 was working well with noisy focusing action when I pressed the shutter half way down. So we can actually verify the modified .LNS file before we write it back to the lens.

This thread is so valuable, thanks to PF and all of the members who contributed to this thread.

Merry Christmas and happy year 2017 to everyone.

Actually the k100d lacks SDM and always works in screw drive mode. The k100d super does SDM and can test if the file works. The k100d should always work in screw drive even before conversion.

[jcdog2006]

Actually the k100d lacks SDM and always works in screw drive mode. The k100d super does SDM and can test if the file works. The k100d should always work in screw drive even before conversion.

Thanks for your response, and now I know why.

Merry X'mas!

[UncleVanya]

Thanks for your response, and now I know why.

Merry X'mas!

The k100d is an excellent way to verify that a screw drive conversion should work.

[HarisF1]

I converted my 50-135 to screwdrive the other day using my k100d. There are more lines to change on these compared to the 16-50.

Also, the store function worked this time around so it was pretty cool to use. Maybe last time I was referring to a different issue. I think it was that I wasn't able to change more than one value consecutively on the camera itself. I kept needing to restart the camera to move onto the next data point.

This time it was straightforward on the PC.

[UncleVanya]

I converted my 50-135 to screwdrive the other day using my k100d. There are more lines to change on these compared to the 16-50.

Also, the store function worked this time around so it was pretty cool to use. Maybe last time I was referring to a different issue. I think it was that I wasn't able to change more than one value consecutively on the camera itself. I kept needing to restart the camera to move onto the next data point.

This time it was straightforward on the PC.

Fantastic!

[spyglass]

I have had 3 SDM motor failures with my DA* 16-50. I paid full repair costs each time with no help or even a care by Pentax / Ricoh. They have not solved the problem (last fix lasted 3 month and only was used twice). Ask the repair center how many lenses they repair. Look at the lengths loyal Pentax users have to go to be able to use their lenses, like conversion tricks. Funny how Pentax only offers a 1 year warranty of their lenses....... while Tamron & Sigma offer 6 & 7 respectively if purchased in Canada.

[UncleVanya]

I have had 3 SDM motor failures with my DA* 16-50. I paid full repair costs each time with no help or even a care by Pentax / Ricoh. They have not solved the problem (last fix lasted 3 month and only was used twice). Ask the repair center how many lenses they repair. Look at the lengths loyal Pentax users have to go to be able to use their lenses, like conversion tricks. Funny how Pentax only offers a 1 year warranty of their lenses....... while Tamron & Sigma offer 6 & 7 respectively if purchased in Canada.

Just have to ask - who repaired the lens and did not give more than 90 days warranty.

[slip]

I have had 3 SDM motor failures with my DA* 16-50. I paid full repair costs each time with no help or even a care by Pentax / Ricoh. They have not solved the problem (last fix lasted 3 month and only was used twice). Ask the repair center how many lenses they repair. Look at the lengths loyal Pentax users have to go to be able to use their lenses, like conversion tricks. Funny how Pentax only offers a 1 year warranty of their lenses....... while Tamron & Sigma offer 6 & 7 respectively if purchased in Canada.

Pentax should be offering screwdrive conversion free as an option to their pathetic SDM design issues

Randy

[willskywalker93]

Just did this with mine after its second SDM bit the dust. Pretty annoying. I had noticed it being sluggish for a few months and needing to warm up. Left it sitting for a month for school, and it's dead. None of the usual wake up tricks did a thing. I want to go to the sigma because it has less flare/fringe/other aberrations than the 16-50, but I'll lose weather sealing and full time manual capabilities. What to do....

After an hour of trying to get to the debug menu of my K5 since I'd read that the K3 couldn't be used for lens rom edits, I gave up and switched the to KX. Found the MODSET.492 file name easily, took me forever to find a thread saying I had to hold the AV button down on boot to get me there. The 16-50 actually focuses much more accurately and quickly in screw drive now. The noise is just weird for my now, I've got the Sigma 70-200 HSM II, the DA 18-135 WR, and the BigmOS, so focus noise was a thing of the past when my 16-50 was functioning. Alas, it is back. Like an itch on that one part of your back that you just can't quite reach.

Anyway, rant over. Thanks for the guide, OP! Much appreciated. Good to have a working lens again.

[HarisF1]

Just did this with mine after its second SDM bit the dust. Pretty annoying. I had noticed it being sluggish for a few months and needing to warm up. Left it sitting for a month for school, and it's dead. None of the usual wake up tricks did a thing. I want to go to the sigma because it has less flare/fringe/other aberrations than the 16-50, but I'll lose weather sealing and full time manual capabilities. What to do....

After an hour of trying to get to the debug menu of my K5 since I'd read that the K3 couldn't be used for lens rom edits, I gave up and switched the to KX. Found the MODSET.492 file name easily, took me forever to find a thread saying I had to hold the AV button down on boot to get me there. The 16-50 actually focuses much more accurately and quickly in screw drive now. The noise is just weird for my now, I've got the Sigma 70-200 HSM II, the DA 18-135 WR, and the BigmOS, so focus noise was a thing of the past when my 16-50 was functioning. Alas, it is back. Like an itch on that one part of your back that you just can't quite reach.

Anyway, rant over. Thanks for the guide, OP! Much appreciated. Good to have a working lens again.

The SDM unit is quiet but takes a split second to start spinning (inertia) whereas the screwdrive jerks quite quickly into action. That's probably why it seems so much faster. It's more responsive.

[UncleVanya]

Just did this with mine after its second SDM bit the dust. Pretty annoying. I had noticed it being sluggish for a few months and needing to warm up. Left it sitting for a month for school, and it's dead. None of the usual wake up tricks did a thing. I want to go to the sigma because it has less flare/fringe/other aberrations than the 16-50, but I'll lose weather sealing and full time manual capabilities. What to do....

After an hour of trying to get to the debug menu of my K5 since I'd read that the K3 couldn't be used for lens rom edits, I gave up and switched the to KX. Found the MODSET.492 file name easily, took me forever to find a thread saying I had to hold the AV button down on boot to get me there. The 16-50 actually focuses much more accurately and quickly in screw drive now. The noise is just weird for my now, I've got the Sigma 70-200 HSM II, the DA 18-135 WR, and the BigmOS, so focus noise was a thing of the past when my 16-50 was functioning. Alas, it is back. Like an itch on that one part of your back that you just can't quite reach.

Anyway, rant over. Thanks for the guide, OP! Much appreciated. Good to have a working lens again.

I recently converted a 50-135 that was having focusing issues in low light in a k-1. My testing if the lens showed that while SDM was functional it seemed to fail to focus under some circumstances - perhaps giving up too soon as the SDM lagged perhaps. The conversion hasn't been tested by the user but I thought I would post this to see if others have seen this scenario - SDM works and isn't sluggish per say but fails to lock focus in poor lighting more than expected. In these cases has Conversion to screw drive helped? In this case on my k-3 and k100d super it seems to have had a positive impact. Waiting for customer to validate with his k-1.

Note: I tested my own 50-135 in the same focusing challenges and mine with SDM enabled did not fail nearly as often. 1/10 as often perhaps. The screw drive conversion was better than before perhaps failing 2/10 of the original 10 failure scenarios.

[HarisF1]

I recently converted a 50-135 that was having focusing issues in low light in a k-1. My testing if the lens showed that while SDM was functional it seemed to fail to focus under some circumstances - perhaps giving up too soon as the SDM lagged perhaps. The conversion hasn't been tested by the user but I thought I would post this to see if others have seen this scenario - SDM works and isn't sluggish per say but fails to lock focus in poor lighting more than expected. In these cases has Conversion to screw drive helped? In this case on my k-3 and k100d super it seems to have had a positive impact. Waiting for customer to validate with his k-1.

Note: I tested my own 50-135 in the same focusing challenges and mine with SDM enabled did not fail nearly as often. 1/10 as often perhaps. The screw drive conversion was better than before perhaps failing 2/10 of the original 10 failure scenarios.

@UncleVanya

I've seen the same behaviour with my 50-135mm. Hunting takes a lot of small movements and I think the SDM just isn't up for it so the camera gives up. At f/2.8 the lens is wide enough to lock on focus when seeing might be difficult (and screwdrive helps in this case).

[UncleVanya]

@UncleVanya

I've seen the same behaviour with my 50-135mm. Hunting takes a lot of small movements and I think the SDM just isn't up for it so the camera gives up. At f/2.8 the lens is wide enough to lock on focus when seeing might be difficult (and screwdrive helps in this case).

That's a good way to sum this up. My lens didn't seem to give up. His did. At least with SDM. Ironically I bought my lens as failed SDM but I woke it up and it never gave me trouble again. I am pretty sure mine was from the Pentax offices closing out and may have had an SDM replacement motor and just sat on the shelf too long. Waking it was painless and it hasn't ever been a problem since.