Originally posted by paulzhere Has anybody faced such a problem before, or does anyone have an idea as to what the problem might be? Any help is highly appreciated.
Originally posted by Sterby What camera are you using?
As Sterby suggests, your experience may be related to your camera. Your profile indicates that you shoot with a K-50. If you are still using that camera, it may be the source of the problem. There is a known problem with both the K-30 and K-50 that involves aperture control.
You can evaluate the lens off-camera by working the aperture actuator by hand. If the action is smooth without binding or hesitation, it is unlikely that the problem is with the lens.
You can evaluate the aperture mechanism on the camera by setting the mode to "B" and releasing the shutter while looking into the front of the lens at various apertures. If the aperture does not fully open after releasing the shutter, you have problems. Similarly, if the aperture does not stop down appropriately (incrementally smaller at larger f-numbers), things are not right.
If there is a problem with the body, warranty service would be your best option. If the camera is no longer under warranty, a repair by the Ricoh/Pentax authorized service center will likely cost between $200 USD and $250 USD. Other options have recently been suggested, but I have no personal experience and cannot recommend.
Steve