DA* 50-135 Lens Problem

Hi all,

I don't seen to be having much luck lately, my K3-II has gone in for a check/warranty repair and now I seem to have a lens problem.

My DA* 50-135 won't focus, it tries to focus but just keeps going backwards and forwards and making a whirring noise, manual focus seems ok though.

Is this a sign of SDM failure, I've had the lens since April 2013 and it gets regular use during the oval racing season, it's my most used and favourite lens.

I've tried it on my K5 and K5-II bodies and it's the same on both.

If it is an SDM problem does anyone have any idea about repair costs and where would I send it.

Regards.

Chris.

Firstly try and get it diagnosed to make it sure it's an SDM problem. Get a quick video of the lens in action and post it on here. If that's not possible then just make sure that it's only this lens that has the issue. You've more or less done this by trying the lens on the other bodies.

Secondly try to clean the contacts with contact cleaner or isopropanol.

Thirdly (assuming it's only this lens that's messed up), if the lens has some AF movement then try to keep the AF button pressed while you manually turn the focusing ring - this might free up the mechanism. If it works, then simply do this every time you use the lens and it'll hopefully stay in good shape.

Lastly, if there's no AF movement or the lens is still not responding then you can convert it to screwdrive. The K-5 will be fine to use and there are tutorials online. Screwdrive operation is not that loud and you might gain a bit of AF speed to go with it. The best part is that it's free!

How long is it since you used it last? I had one which was not in regular use and I had to "wake it up" by winding the focus ring back and forth a few times. A word of caution though, it got me so annoyed one day, I think I've dislodged one of the elements being too vigorous with the wake up call. My advice would be to have it converted to screw drive.

The last time I used the lens was October 2018, the last race of the season.

I'll try and give it a 'wake it up' tomorrow.

My 50-135 has the SDM problem and the problem is that it won't focus at all.
Manual focus works ok but the auto focus does not move at all. There is no hunting for focus and I understand that this is the usual failure.
Basically I use it as a manual focus lens with no problems and have not got around to converting to screw drive, intend to take the plunge but have not go around to it yet.

Sounds like you have a different problem to the usual SDM failure, if the lens focus is moving and trying to focus. Might need to be seen by the menders.

I've just had another go at sorting the lens out without any luck.

It will focus lock on the very odd occasion but 99.9% of the time it won't.

When i try to focus the focus scale on the top of the lens is just keeps spinning and clunking back and forth between the infinity mark and the 1 meter mark.

Regards,
Chris.

SDM will be fine then. You've got a problem elsewhere (maybe in the quickshift clutch system)

** Update **

I've just been over to JP Technical to pick up my repaired lens, all seems to be working fine again.

This is the work they carried out,

Check, adjust and calibrate focusing
Replace, calibrate and repair electronic circuit board
Repair focus movement
Repair lens assembly
Replace mechanical assembly

Cost - £187.80

Regards,

Chris.

I've had to take my DA* 50-135 back to JP Technical again for another focus issue.

The repair they originally did is fine, no problems at all.

It turns out that the new issue is that lens is de-centred and it would have to be sent to France to have the repair done.

I have been told that the repair could be around £180.00 'ish again, I've had the lens for 5 years and have already spent £187.80 on having it repaired first time so I've bitten the bullet and ordered a new one through SRS.

I'll pop over to JPT next week and pick up the old lens.

Regards,

Chris.