Pentax SDM issues (like everyone else)

Dtabbler · 08-11-2020, 04:04 PM - **1 Like**

figured out my screwup... didn't have the aperture thingy in the right spot.

SSGGeezer · 08-11-2020, 05:10 PM - **1 Like**

Originally posted by Dtabbler

figured out my screwup... didn't have the aperture thingy in the right spot.

I suspected that or compensation got moved between remounting the lens after conversion. Simple things often create what appear to be big issues! I thought my K-1 was going wacky but I had changed the mode to X-process with my face! took me 15 minutes to figure it out!

dlhawes · 04-26-2021, 05:08 AM

I have never seen any explanation of what it is, exactly, that goes wrong with these SDM contraptions. That really bothers me. I've seen all sorts of theories about dust, contamination, corrosion, condensation, and there's one guy who made a video about taking the thing apart and filing down the ends of what looks like a tiny horseshoe magnet. But I've never seen any kind of competent analysis of the failures. Anybody know anything about this?

**UncleVanya** · 04-26-2021, 06:00 AM - **1 Like**

Originally posted by dlhawes

I have never seen any explanation of what it is, exactly, that goes wrong with these SDM contraptions. That really bothers me. I've seen all sorts of theories about dust, contamination, corrosion, condensation, and there's one guy who made a video about taking the thing apart and filing down the ends of what looks like a tiny horseshoe magnet. But I've never seen any kind of competent analysis of the failures. Anybody know anything about this?

I think you may be mixing up the aperture block failure with sdm, but I could be wrong, if you find that video please post it. The aperture block failure does not affect sdm lenses it affects the camera body. The best repair involves replacing the solenoid, a less effective long term solution is to file the solenoid.

Sdm causes? Only Pentax/Hoya/Ricoh knows the true cause and scope. It could be a combination of factors. Ultimately all we can say for sure is that some failure rates seem higher than acceptable.

**scc** · 04-29-2021, 12:38 PM

Both my 17-70 an 60-250 have had a SDM failure. They were both repaired and if the 60-250 has worked flawless since then, the 17-70 is again experiencing SDM issues. It takes time to revive the AF when the lens has not been used for a while but ultimately it works.

**UncleVanya** · 04-29-2021, 07:52 PM

Originally posted by scc

Both my 17-70 an 60-250 have had a SDM failure. They were both repaired and if the 60-250 has worked flawless since then, the 17-70 is again experiencing SDM issues. It takes time to revive the AF when the lens has not been used for a while but ultimately it works.

I'm sorry to hear that. I had a refurbished 17-70 - which I gifted to my niece and she still uses it without problems. She's using the DA 50 f1.8 I gave her more now however so I hope the 17-70 remains useful to her in the future. I always found the images from the 17-70 to be quite good at all focal lengths. It reminds me of the 60-250 and is a good paired lens if f4 is adequate for your needs.

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08-11-2020, 04:04 PM - 1 Like	#46
Dtabbler New Member Join Date: Sep 2011 Posts: 15 Original Poster	figured out my screwup... didn't have the aperture thingy in the right spot.

08-11-2020, 05:10 PM - 1 Like	#47
SSGGeezer Veteran Member Join Date: Jun 2017 Location: Indiana, U.S. Photos: Gallery \| Albums Posts: 4,845	Originally posted by Dtabbler figured out my screwup... didn't have the aperture thingy in the right spot. I suspected that or compensation got moved between remounting the lens after conversion. Simple things often create what appear to be big issues! I thought my K-1 was going wacky but I had changed the mode to X-process with my face! took me 15 minutes to figure it out!

04-26-2021, 05:08 AM	#48
dlhawes Guest	I have never seen any explanation of what it is, exactly, that goes wrong with these SDM contraptions. That really bothers me. I've seen all sorts of theories about dust, contamination, corrosion, condensation, and there's one guy who made a video about taking the thing apart and filing down the ends of what looks like a tiny horseshoe magnet. But I've never seen any kind of competent analysis of the failures. Anybody know anything about this?

04-26-2021, 06:00 AM - 1 Like	#49
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,385	Originally posted by dlhawes I have never seen any explanation of what it is, exactly, that goes wrong with these SDM contraptions. That really bothers me. I've seen all sorts of theories about dust, contamination, corrosion, condensation, and there's one guy who made a video about taking the thing apart and filing down the ends of what looks like a tiny horseshoe magnet. But I've never seen any kind of competent analysis of the failures. Anybody know anything about this? I think you may be mixing up the aperture block failure with sdm, but I could be wrong, if you find that video please post it. The aperture block failure does not affect sdm lenses it affects the camera body. The best repair involves replacing the solenoid, a less effective long term solution is to file the solenoid. Sdm causes? Only Pentax/Hoya/Ricoh knows the true cause and scope. It could be a combination of factors. Ultimately all we can say for sure is that some failure rates seem higher than acceptable.

04-29-2021, 12:38 PM	#50
scc Loyal Site Supporter Join Date: Dec 2012 Posts: 165	Both my 17-70 an 60-250 have had a SDM failure. They were both repaired and if the 60-250 has worked flawless since then, the 17-70 is again experiencing SDM issues. It takes time to revive the AF when the lens has not been used for a while but ultimately it works.

04-29-2021, 07:52 PM	#51
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,385	Originally posted by scc Both my 17-70 an 60-250 have had a SDM failure. They were both repaired and if the 60-250 has worked flawless since then, the 17-70 is again experiencing SDM issues. It takes time to revive the AF when the lens has not been used for a while but ultimately it works. I'm sorry to hear that. I had a refurbished 17-70 - which I gifted to my niece and she still uses it without problems. She's using the DA 50 f1.8 I gave her more now however so I hope the 17-70 remains useful to her in the future. I always found the images from the 17-70 to be quite good at all focal lengths. It reminds me of the 60-250 and is a good paired lens if f4 is adequate for your needs.

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