Sigma 24MM F2.8 help

I just got a sigma 24mm f2.8 lens pentax k lens and it doesn't fit my k50 or kp, what am I doing wrong?

How old is the lens?

I have a number of Sigma 24 & 28 mm lenses and have no problem with using them on my Pentax cameras.

Perhaps take a picture of the lens and upload it.

jim yeats wrote:

Just above the mount is stamped pentax k, red dots lined up and won't seat.

I have Sigma 24/2.8 for Pentax K (really nice little lens, BTW), and mine looks like this:

This is "A" version (manual focus)

If your lens is really Pentax K version, then its mount is damaged, check bayonet flanges...For example, it is possible that the lens has dropped and the flange is bent.

Ari

This looks like an old Ricoh PK mount to me. Caution:  do not force mount it on your body! The lens pin is liable to get stuck, and you might be unable to unmount the lens.

Cheers,

AlainCo

jim yeats wrote:

this doesn't look like my other pk lens mounts

Yes , all my old Sigmas look very different.

The , both , pin ( link ) and protector are differently shaped , and the protector is located just next to the link.

I had similar problem on some old PK mount lenses.

I had to remove the protector , in my cases it was just too big , see attached photos on my old Vivitar.

Some people just trim the link and protector with some kind of timing tool , like Dremel.

Vivitar Series 1 70-210mm f/3.5 (Version 2) - made by Tokina

Vivitar Series 1 70-210mm f/3.5 (Version 2) - made by Tokina

iTrax wrote:

jim yeats wrote:

this doesn't look like my other pk lens mounts

Yes , all my old Sigmas look very different.

The , both , pin ( link ) and protector are differently shaped , and the protector is located just next to the link.

I had similar problem on some old PK mount lenses.

I had to remove the protector , in my cases it was just too big , see attached photos on my old Vivitar.

Some people just trim the link and protector with some kind of timing tool , like Dremel.

Vivitar Series 1 70-210mm f/3.5 (Version 2) - made by Tokina

I've seen this problem on quite a few independent PK lenses. In many cases the black ring at the rear which the diaphragm lever protector is attached to can be taken off entirely after removing the black screws.

Here's an example of such a lens that we sold some time ago with more explanation and pictures. This one had a second sleeve that came out as well, but this isn't always the case:

https://www.heritagecameras.co.uk/75-200mm-mc-zoom-lens-with-macro-for-pentax-k-m-pk-35mm-film-slrs-ka-easily-modified-for-af-digital-2835-p.asp

Ring removed from PK lens for compatibility with Pentax AF and digital SLRs