SMC Pentax and Canon 50mm 1.4 question
 

Just about to receive my T2i in the mail and have no real prior experience with Canon DSLR's. I have laying around a SMC Pentax-M 1:2 50mm (has the two black plastic tabs on the mount side).

My first question is, would this work (getting an adapter at B&H) along with has any one experienced any difficulties with these prime lens'?

Secondly I came across a used Canon FD 50mm f/1.4 S.S.C. Prime Lens. These are the older versions of what a lot of people are talking about working great on the T2i so I am wondering if the $80-100 price tag on these are too good to be true? Any possible issues mounting these also?

Realistically I believe I should just get the adapter for the Pentax and see what results I get from that and go from there since it is relatively fast (compared to my 18-55 kit lens).

Any advice and/or input would be appreciated greatly.

Thank You

link to the canon lens:

Canon FD 50mm f/1.4 S.S.C. Prime Lens F-1 A-1 EX - eBay (item 380238045432 end time Jun-28-10 08:41:09 PDT)

Firstly, don't bother with the FD. You cannot adapt these for use on EF/EF-S mounts and retain infinitiy focus without using an optical element. The FD/EF adapters advertised on eBay are JUNK. There are some kicking around made by canon, but these are rocking horse crap, and you will never find one.

If I were you, I would buy that adapter. Pentax-M lenses are know to adapt well to the EF mount. Check if that B&H one has a focus confirm chip, and compare prices to eBay offerings. The chip means you still get the illumination of focus points and beep, which helps enourmously on a manual focus lens.

James - Since the lens is so old will it work with the focus confirm chip adapter? Reading the description of it on an ebay listing made me believe it is for newer Pentax lens'.

I could be completely wrong.

And thank you for the reply.

The Pentax-M is known to obstruct the mirror on the 5D2 - not sure about the 550D.

There is a workaround which is valid for all Pentax M and A versions.

Use a jewellers screwdriver to remove the three small screws which hold the black plastic baffle, the screws are 120 degrees apart and are located in the groove of the metal mount. Remove the baffle by the lug which is near the aperture lever. Then, use a stanley knife to pare down the lug on the baffle until it is flush (careful you dont cut yourself). Before putting the baffle back use tin snips to shorten the aperture lever. When re-assembled you will have a lens which is useable on the 550D and the 5D2.

The nice thing about old Pentax lenses is that they are cheap and have buttery smooth focus and have decent focus throw, the SMC coating gives a nice tonal aesthetic.

Watch out for the M 28mm F2.8 on ebay it is so cheap and gives great results as a standard lens ~ 44mm.


Enjoy your lens

Hi Sean,

This is a great resource to find out what lens brands are adaptable to the Canon mount:

Canon EOS lens Adapters - Manual focus lenses on Canon EOS bodies

So in essence I am just getting both the baffle (longer black piece, on the inner side of the aperture lever) and the aperture lever to sit flush with the rest of the lens? In other words instead of having those two sticking out, this is making them flat along with the rest of the lens.

I am going to be getting the adapter tomorrow and see how it fits or if it is even able to fit before I modify the lens because if I can avoid taking it apart that would make me happy.

Thank you John. And indeed these are buttery smooth focus rings! I just got the camera about an hour ago and the kit lens' ring seems like it will be tricky to maneuver effectively but nothing some patience cant change.

Cheers

If you do end up taking the lens apart, while you've got it open you can lift the aperture ring off and remove the tiny bearing to 'de-click' the ring and give you continuous aperture adjustment, great for precise exposure adjustment. I added a 1/4" strip of metal tape to the inside of the aperture ring before putting it back on to tighten it up a bit.

Not necessary on EF-S cameras (550d). The mirror is smaller.

The focus confirm chip does not care what lens it sits on. It merely talks to the camera, and says basically, hi, I'm a lens. Focus confirm does not rely on anything in the lens, it's just that Canon saw fit to not activate the feature unless a recognised lens was attached.

In short, if you have an adapter that mechanically fits both lens and camera, if it has a focus confirm chip on it which is correctly aligned, it will work.

In really short, it will work.

Thank you James

Just realized this is a K-mount lens. I can get my hands on an adapter without focus confirm. Is it worth it?