Pentax smc DA* 50-135mm SDM Issue

Demoguy wrote:

On Tuesday I went to Everett Wa. to look at a possible project. The Nimitz, CVA 68 is back from a long deployment so I thought I would stop along the waterfront and take some photos. I pulled out my camera (k-3) with the DA* 50-135 on it and lo and behold, no auto focus. I bought this lens last year on black Friday, so its three weeks out of warranty. Anyway it was @ 29 deg F so I ended up using manual focus and with my bad eyes the result was not so good. Today I mounted the lens on my K-5 and nothing happened, then on the K-01 and it woke up. Tried it on all the other cameras and it worked fine. I wonder if it was just cold or if this is a sign of SDM failure.

Has anyone had this lens fixed at CRIS recently and would you have a cost?

Thanks,

Joe

Given it only happened the once it's all to easy to run round the room screaming SDm failure as seems to be the forum norm.!

The reality is in order of most likely ( 1 off occurrence).

1. AF/MF switch not seated in AF correctly

2. three way gear/clutch mechanism out of Sync

3. SDM tightening

4. seals slipped

5. Seals hardening/ diirt in barrell

6. gear damaged

options 1 and 2 are no cause for concern.

option 3 will be noticeable in that though AF will now function it will be slower than previous, You can easily asses this, In a free focusing 50-135 the lens will be fractional quicker short -> infinity than back again , the whole proses would take < 1.5 secs. If they are the same speed and greater than 1.5 sec then suspect you may have SDM motor beginning to bind.

for options 4-5 you can manual spin the focus barrel it should appear loose and tacky

If it feels tight, gritty or well damped you have a problem.

Though 3,4 and 5 are classed as SDM failure only 3 will be 'fixed' by modifying the microcode to allow screw drive.

It is relatively unusual for SDM to fail inside 2 years normally waiting till the 'nomal' warranty period outside the US has expired (24 months).

Check your consumer protection laws as in the UK we are covered for 6 years for 'faulty design' and I had my 4.5 year old 50-135 replaced by Pentax UK FoC (after some frank discussions).