[MrApollinax]

Use the directions in this link and fire a test shot:

K100D (Super) Pictorial guide to using manual lenses [imgs] [Page 1]: Pentax SLR Talk Forum: Digital Photography Review

Post the test shot after following those steps here. From your descriptions it sounds like you are not stopping down the lens before taking your shot.

[Marc Sabatella]

How ever when i opened the photos in Photo browser i still don't see the Aperture setting..

Right, as others have said, the camera is not able to read the aperture ring, so it has no idea idea what aperture you used.

I took few pictures by settings different values in the Aperture ring on the lens and all the pics look almost the same and none have aperture value when opened in the Photo Browser.. I shot all these in Manual (M) mode..

Irrespective of the Aperture value i have set on the lens the shutter speed is always set to 1/60 sec.

One of these statements is wrong. If you shot in M mode at differen apertures but the same shutter speed, there is no way the pictures would look the same - only one or two would be exposed well. Ones with too large an aperture (small f-number) would be overexposed, and ones with too small an aperture would be underexpose. So I'm guessing you werne't actrually in M mode but rather Av or some other mode. And as others have said, those modes don't work with manual lenses. The aperture ring is completely ignored (meaning you shoot wide open p f/2) in all modes but M. So perhaps you meant o say you were in manual focus mode, but were not in M exposure mode?

Anyhow, you should go to the beginner's forum and check the sticky note on how to use manual lenses. It explains the whole process.

[simico]

I just bought a Pentax M 50mm F2 lens yesterday and after ~30 test shots I can safely say that screwing up a photo is very easy with such a large aperture Approx. half of the photos was blurry due to either totally missed focus or not the intended area being in focus (it was mostly front focus).
I noticed that I cannot trust only my eyes or only the AF focus confirmation! I have to move the focusing ring very slowly, wait for the focus confirmation and further adjust focus (within the "confirmed zone") using my eye - this increased the number of successful shots drastically. I think its very challenging (both for our eyes and for the AF system) to find perfect focus at F2 and the smallest mistake is clearly visible on the photo (unlike at F4-5.6 and higher, where larger DOF hides small mistakes).

[Mike Cash]

I noticed that I cannot trust only my eyes or only the AF focus confirmation! I have to move the focusing ring very slowly, wait for the focus confirmation and further adjust focus (within the "confirmed zone") using my eye - this increased the number of successful shots drastically.

You're not one of those people who think the red square is the focus confirmation, are you?

[malakola]

i had been experiencing same that problem. in my case
when i push a shutter, a mirror jumps up and is closed again, the focus ring is a little shift because lens is not fit.

[simico]

You're not one of those people who think the red square is the focus confirmation, are you?

No, I'm not. That's the first thing I disable (and set center only AF point) on every DSLR in my hand. My current cam don't even have red squares