Art and Photography

Pentax lens repair...............Failed SDM

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  • Nov 16th, 2016 3:34 pm
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Sr. Member
Aug 3, 2011
935 posts
159 upvotes
Toronto

Pentax lens repair...............Failed SDM

Posting for a friend who's Pentax 50-135 SDM has stopped auto focusing. Called Henry's , they are charging $50 for diagnostics and would adjust that 50 If one chooses to get it fixed from them.
Any other options ?
Bumped into a video which claims that the SDM mechanism can be over ridden and screw drive can be activated on the lens.............any insights on this too please ?

Thanks
2 replies
Deal Addict
Dec 20, 2007
4713 posts
6306 upvotes
Prince George
Yes I did that on my 50-135 (got cheap off eBay because the SDM had failed). The conversion to screw drive requires specific older bodies. For some reason my K-30 cannot upload/download the firmware from the lens so I had to borrow a different body to do it. I used a K-x.

You can find all the gory details over on pentaxforums.com. The gist of it is, you use the body to download the lens firmware to a file on the SD card. Back up and edit the lens firmware file and upload it back to the lens. Thereafter the lens will tell the body (any body to which it is attached) that it doesn't have SDM and the body will fall back to screw drive.
Member
Feb 3, 2009
205 posts
21 upvotes
There are many posts on the pentaxforums.com forum regarding the conversion of SDM lenses to regular screw drive mechanism. This was done with firmware heck on the lens. The 50-135/f2.8 lens has superior optics and weather resistance. If the cost to repair is not much, it is worth to just keep it.

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