[CincySig]

When I attach this lens the view finder is so dark it is hard to see subject matter and get a good focal point. Any ideas?

[KevinR]

Is the lens set to A on the aperture ring..??

If it is, then demount it an flick the aperture lever to see if it moves the aperture blades, and also check if the aperture lever is bent.

[CincySig]

Yes it was set to A. If I mount it not in A the camera doesn't seem to know what to do. The blades open and close if I change the aperture. Aperture setting just blinks and camera won't work. I guess it just is not as compatible as I had hoped. I have had the lens for close to 20 years. The K-30 is my first DSLR camera. I have had three other 35mm Pentax cameras so was hoping my old lenses would work seemlessly, that does not seem to be the case.

[KevinR]

This lens should work just fine. Almost all old pentax mount lenses work on new dslr's. Something is apparently wrong imho.

Does the viewfinder light level change if you move the aperture ring with the lens mounted..?

The aperture lever should hook on the aperture mechanism in the camera and keep the aperture fully open until the optical preview or shutter is released. If this is not catching due to misalignment or bent aperture lever on lens, the lens will behave like a preset aperture lens.

[CincySig]

OK. I will take a closer look. I do know that if I manually set the aperture the viewfinder gets much brighter as I open it to larger apertures. I can not see anything misaligned.

Thanks so much.

[KevinR]

That sound like the aperture lever is not making contact, or the camera aperture pusher is not working. Forgive the implication, but I assume you have a camera that works with another lens.

Assuming camera works with another lens, your lens lever could be:
a. bent in very slightly
b. too short
c. bent downwards

If you have had the lens for 20yrs, I would go with a. as the most likely cause and very slightly bend the lens aperture lever radially outwards.

[Canada_Rockies]

If the aperture lever bend is not the cause, in the menus set [Use Aperture Ring] to on. You can then manually meter and expose with the green button, or whatever the equivalent is on your model Pentax (AE-L?). Set the mode dial to M to do this. You can also use it wide open only in A, but it won't know what you have set the aperture ring to.

[bluestringer]

Mount the lens with the aperture ring set to wide open, then rotate the ring to each stop while looking through the viewfinder, if the view gets darker with each setting then the lever on the lens is not making contact with the camera. If you are using the lens in manual and not on A, then you will need to set aperture permitted in the custom settings. The camera will not fire if this is not set. When setting the lens on any f stop other than A setting, only F---- will show on the display.