Manual Focus Lenses Forum

canoneer · Joined: 16 Mar 2009 Posts: 18 Location: So Cal, USA

So I just won an auction for a Cosina 55 1.2 on ebay this morning and am very excited about it. My only question is about the mount on the lens. What mount is it and what adapter would I need for it to fit on my 20D?
The auction didn't have much info regarding the lens and mount, so I'm hoping it's in good working condition when I receive it. Confused

I was under the impression that the Cosina/Tomioka lenses are Pentax mount lenses. I don't know much about pentax, but I've read that there's a K mount and some other types.

Any help is appreciated guys. Thanks

no-X · Tue Mar 17, 2009 6:17 pm

The former Tomioka (/Cosina) 55/1.2 is M42 lens. Cosina later produced 55/1.2 for Porst and Revue in Pentax mount. Maybe there's a Cosina labeled version of the later lens...

canoneer · Joined: 16 Mar 2009 Posts: 18 Location: So Cal, USA

Well this one is not M42, here are a couple pictures. (Guess I should have thought of that the first time). I'm not too familiar with different mounts so I can't recognize the one in the shot, is this the Pentax mount?

no-X · Tue Mar 17, 2009 6:45 pm

99% yes

canoneer · Joined: 16 Mar 2009 Posts: 18 Location: So Cal, USA

Great, thanks.

Now the question is which Pentax mount? Looking on ebay I see PK mounts, K mounts, and a few that only say Pentax mount... which is the right one for me? Confused

Link 1, Link2, Link 3?

no-X · Tue Mar 17, 2009 8:27 pm

Pentax K-mount, shortly PK-mount is the same thing. There is only one Pentax mount for 35mm film cameras Smile

canoneer · Joined: 16 Mar 2009 Posts: 18 Location: So Cal, USA

Ah thanks for clearing that up and helping me out! I really appreciate it. I'll post images once I get it all set up.

hintheman · Joined: 12 Jan 2009 Posts: 51 Location: Fremont, CA

How are you going to use this Pentax K mount on Canon bodies? I have this lens and it is quite a lens that Pentax users go after.

Unlike a M42 mount that I can use Av aperture, those K mount lens are like Pentax M lens. In my Pentax K20D bodies, I have to use stop-down metering to get exposure.

I have few blog posts using the lens in Pentax bodies, it is a decent manual lens.

Initial test shots
http://techtheman.blogspot.com/2008/11/cosina-55mm-f12-test-shots.html

In aquarium needing a fast shutter on moving fish
http://techtheman.blogspot.com/2008/12/cosina-55mm-f12-in-aquarium.html

with +4 close up
http://techtheman.blogspot.com/2008/12/cosina-55mm-f12-with-4-close-up.html

I do notice that my copy has aperture blades don't close down to circular shape in small apertures. Somehow, ringed lights in background sometimes show in oval shape.

canoneer · Joined: 16 Mar 2009 Posts: 18 Location: So Cal, USA

Haha I've been checking your pages out a few times while researching this lens. Nice examples, I especially like the +4 close ups. I don't mind the oval shaped bokeh lights that I've seen with this lens, I actually kind of like them.

Are you asking me specifically how I plan to use the lens?

I was under the impression that I could use the PK - EOS adapter and manually control everything in order to use the lens. Correct me if I'm wrong.
If I'm wrong and the Cosina can't be used on EOS bodies, then there will be a Cosina back up for sale on ebay in a few days!

hintheman · Joined: 12 Jan 2009 Posts: 51 Location: Fremont, CA

Thanks for the reply. I am not aware of PK mount to EOS adapter, it is likely my ignorance on Canon gear. I hope others can jump in with a link to adapter that you can trust. Cosina is is a great lens that I learn from others.

The oval shaped bokeh doesn't bother me. I like imperfection so that the lens is unique with character. If you happen to find that you like the lens, I highly recommend the add on for a lens hood. The lens front element is quite big in 58mm size and I use a lens hood for protection and mount it semi-permanently on the lens. And the +4 close up will get you closer to flowers and others.

You can see the lens hood in this picture

and I get it from heavystar in ebay that sell the hood in 58mm size and the end cap in 62mm size as a combo for < $10. Link to item in my blog post for +4 close up

http://techtheman.blogspot.com/2008/12/cosina-55mm-f12-with-4-close-up.html

Warmest,
Hin

canoneer · Joined: 16 Mar 2009 Posts: 18 Location: So Cal, USA

Thanks, I'll definitely get the hood and +4 attachment once I see that I actually am able to use the lens with my Canon.

This is the adapter I ended up getting, I hope it actually does work. Ebay Link

Thanks for the info.

hintheman · Joined: 12 Jan 2009 Posts: 51 Location: Fremont, CA

That looks promising. I should get an adapter and bug my buddies in Canon gear to borrow a body to try my K mount lens Very Happy

I find this article from Bot Atkins that talk about the adapters

http://bobatkins.com/photography/eosfaq/manual_focus_EOS.html

and I will suggest to check if the lens rear is too close to the mirror before you mount the lens. Use your Canon lens and compare if the rear of the lens is safe your 20D, especially the aperture lever that looks protected on the rear with a flange.

canoneer · Joined: 16 Mar 2009 Posts: 18 Location: So Cal, USA

That's an interesting article, thanks for the link.

I believe the 5D and higher end EOS bodies are the ones that have the mirror clearance issues. That lever does stick out a bit though, I'll check it out just to be safe.

hk300 · Joined: 30 Oct 2008 Posts: 1041 Location: Hong Kong

i have a Pentax SMC 50 /1.2 and using a Pentax PK to EOS adapter on a Canon 40d.

The aperture lever will be blocked inside the body and i can only use it up fot f4.

canoneer · Joined: 16 Mar 2009 Posts: 18 Location: So Cal, USA

Sent you a PM, hk300.

hintheman · Joined: 12 Jan 2009 Posts: 51 Location: Fremont, CA

hintheman · Joined: 12 Jan 2009 Posts: 51 Location: Fremont, CA

canoneer · Joined: 16 Mar 2009 Posts: 18 Location: So Cal, USA

Thanks for all the resources