Well I am not an expert, but I have some lenses with aperture ring and they work just fine if not set on A.
BUT if I set them on A or I use a lens without aperture ring I get very underexposed pictures. If I put the camera on burst mode and shoot 10-20 pictures it starts to work OK for a while (1-2 hours) then the same problem.

more about this fault I found here:

http://www.pentaxforums.com/forums/151-pentax-k-30-k-50/207619-k30-exposure-prob...

The reason I am looking for this lens is that, my K30 aperture mechanism failed (common fault). So I decided to keep the camera and buy a good lens with aperture ring as my camera works just fine if I set the aperture from the lens directly.
Before it broke I was planning to get the 18-135 WR, but now the 24 -135 is closest to this range and has an aperture ring.

I am located in Romania.

Thanks!

Looking for a Tamron SP 24-135 f 3.5-5.6 or the Sigma 24-135 f 2.8-4.5.
Item shoulf be located in EU due to high postage price.

Thanks!