Help! lens focussing problem...

Hello, I have an interesting issue I wonder if someone can help me with... Having saved up my pennies I just received a DA* 50-135mm lens from SRS. Attaching it to my K7, the focussing will not work. I can kind-of hear a slight whining of the motor indicating it is trying to focus but nothing noticeable actually happens. Also, if I try instead to manually focus, again nothing happens as the focussing ring turns, but the display under the little window at the top of the lens does not move and through the viewfinder the focus does not change.

I already have a DA* 16-50mm lens, which (so far) has worked perfectly on the K7 and still does. I also have a k10d, and attaching the 50-135mm lens to that, the 50-135 seems to work OK. So now I am really confused... on the basis of the 16-50mm lens, the K7 seems to work fine (it also works OK with the DA* 300mm lens) and when attached to the K10d, the 50-135mm lens seems to be OK, but the 50-135 will not work on the K7...

Has anyone come across a similar issue?, or know of/can suggest a solution??? I did wonder whether there could be something firmware-related? I haven't updated the K7 firmware since I bought it...

Any advice gratefully received!

Best Regards

Mat W

When used on the K10 is the camera focusing the lens using SDM or screw drive?

Regards - Steve

You've got me stunned. You shouldn't need any firmware updates. The K7 supports SDM and as you've stated your 16-50mm works fine. The only thing i can suggest is to take your gear into a camera store and try out another 50-135 and see what happens. Sounds like it could be a specific issue with your camera and the lense not the exact model or firware issue. Sorry that I can't be of much help.

Thanks folks. On the K10 the camera is focussing the lens using SDM. Maybe it is a camera issue, although it seems very localised as my other Pentax SDM lenses work fine and I assume they use the same underlying technology...

Hmm

Mat W

OK now i'm even more confused, but in a good way. I thought I would compare the mount of the 50-135 with the 16-50 to make sure they were identical, and I was variously wiggling and rotating all the moving parts of the 50-135 which I could find, and after about 20 minutes of wiggling, rotating, trying the lens, taking it off, trying again, it is now working perfectly on my K7. Having taken it off and replaced it several times now it seems to be consistently working. I have no idea why it wasn't working before, nor why it is working now, but I shall go with it and hope it stays working!

Thanks all

Mat W

Is it new or a used one?

Sometimes I have to do a bit of wiggling and jiggling to get me to work

Jack.

It's an ex-display model from SRS and comes with a two year warranty so I'll keep an eye on it and if the problem recurs I'll take the camera and lens in to have it more thoroughly checked. I have a couple of ex-display items from SRS (a sucker for the reduced price) and have had no problems with anything else. Superficially the lens looks brand new

Jack -Ha! i know exactly what you mean

Cheers

Mat

You could try the firmware update, nothing to lose right?

Thanks Stefan. I did do that as it happens - when I first subsequently tried the lens it wouldn't focus, but then after the wiggling and jiggling it started working and still is, so I don't think it was a firmware issue, but at least it has made me update the firmware...

Best regards

Mat

Could have just been a bit of dirt on the SDM contacts thats gone now?

Could well have been Unlocker. When I was comparing the mounts of the 16-50 and the 50-135, I was running my fingers all over the edges of the mount so if there was any dirt, I would have dislodged it I think, so maybe that was the culprit!

Mat