Please help identify lens/mount! JCPenney 135mm 2.8

[Cabe26]

I picked up this lens at an antique shop today for $10. It is a JCPenney 135mm f/2.8. I have just recently began researching these lenses to adapt to my Canon 5d mk II and am in need of some help to identify this lens and mount. I already have an M42 adapter, so I know that it is not an M42 mount. Is this a K mount? If so, what distinguishes it as a K mount, and what adapter should I use for K to EOS?

The lens reads: 1: 2.8 f= 135mm JCPenney Auto Lens =55mm No. 814135 and says that it is made in japan.

I'm also curious if $10 was reasonable ( I figure $10 is always reasonable) and if this is a good lens that I should keep. They also had a JCPenney 28mm f/2.8 that I might pick up tomorrow for $10. Same mount.

Thank you for your help!

[Andreq]

[Cabe26]

What can I do so that they can be seen? Just post more?

[Andreq]

[Cabe26]

Thanks so much for your help. What is the chipped adapter with focus confirming light? And are there any problems with these lenses hitting the mirror at infinity focus? I've seen some talk about that on the M42 threads and am not sure if the same applies.

Also, since I plan on browsing some more antique shops in the coming days, what can I look for in the mount to determine if it is a Pentax K mount?

[philslizzy]

Looks like Olympus OM mount

[Andreq]

http://www.ebay.com/itm/Big-is-AF-Confirm-Pentax-PK-Lens-to-Canon-EOS-5D-mark-II-adapter-with-cap-/170925788665?pt=US_Lens_Adapters_Mounts_Tubes&hash=item27cbf88df9

The chip is on the adapter and let the camera knows there's a lens. It's mostly fixed to 50mm f1.4, but doesn't affect much the exposition. You do have to find out how your lens behave in A mode anyway. Sometime you go over exposed and sometime under exposed.

I buy most if not all my adapter from Big_is. I find he has the best build quality of them all. I got 2 cheaper one from other seller and they are really crappy.

As for mirror hitting problem, see here http://www.panoramaplanet.de/comp/

I don't have any PK lens to be honest. I've just seen a lot of them latetly since I have a friend with a Pentax DSLR. What I try to look at his the small sliding tab hollowed part that move with the aperture ring (top right on the 3rd picture). The flatness of the mount itself, compared to a C/Y (Contax/Yashica) mount.

Furthermore, don't be temped to buy all those cheap lens. I did it first and ended up with a bunch of really low quality 28mm lenses (you find them so easily and cheap).

It really depends on what you want to shot and how you want to do it. I find that manual focus telephoto are a really nice place to save some money for an hobbyist. You can find good quality 300mm prime for 1/8 of the price of a modern AF lens. A nice fast 50mm f1.4 from mostly any brand can be had for $50. Won't be top of the line primes, but a pretty nice fast lens for indoor shooting and what not.

[Lloydy]

That's an Olympus OM mount, the little pin on the side is the giveaway.

[Cabe26]

Thank you! Do all Olympus OM mounts have the 2 pins on the side? What makes it different from the PK mount?

[DigiChromeEd]

[luisalegria]

This is ALMOST like PK. For that matter its almost like Nikon also.

Olympus mount lenses actually nearly mount on PK bodies. Not quite, but almost.

The visual differences -

Two buttons on the sides, as seen here, one is a lens mount release the other is a manual stop-down.

No hole or slot on the mount "flat" for the PK locking lug. PK is similar to Nikon in this, but the slot is in a different location.

These are the easiest indicators.

[philslizzy]

Some OM fitting lenses only have one button, the one that releases the lens from the camera.

[Cabe26]

You guys are the best.. Thanks for all the info