Please help me identify this 50mm prime

CWyatt · 08-24-2009, 09:27 PM

(Just a note that I have just read the the 'Yellowing Super-Tak == SMC?' thread too)

I've just got hold of a 50mm f/1.4 screw-mount prime, which my Dad got with his Ricoh in the early 1970's. I have been through the lens review database but can't decide exactly which lens it is.

There's no sign of fungus (as far as I know) but the glass has a very strongly sepia/yellow tinge.

The lens came in a little leather box, which it's been in for about twenty years.

The lens reads:
Super-Takumar 1:1.4/50 3397174
Asahi Opt. Co. Lens made in Japan

Can anyone link me to this lens in the review database (or similar)? Thanks

Just1MoreDave · 08-24-2009, 09:48 PM

Super-Takumars often have exactly this kind of yellow reflection from the front element. The rear element often has a purple reflection. You can see if the lens has the yellowing problem from decaying radioactive elements in the glass by opening the aperture and looking through the lens at a white piece of paper. It helps to compare the lens to another lens to see how yellow it is.

Steinback · 08-24-2009, 09:51 PM

Like it says on the front ring, that's a Super Takumar 50mm f/1.4. All of the versions of the lens are grouped together in the lens review forum: Pentax Lens Review Database - 50mm F1.4

I've got one that's very similar with a serial number just under 2.2 million. Worth buying an M42 to K adaptor for if you don't already have one for your current body.

If you don't like the yellow leave the lens in a sunny (but preferably not too hot) window for about a week with aluminum foil lining the rear lens cap and the front cap off and it should clear right up again. After about a year of being stored in its case when not in use mine is starting to turn yellow again.

stevebrot · 08-24-2009, 09:52 PM

Based on the lettering, I would guess that to be a Super Takumar 50/1.4 (Pentax Lens Review Database - 50mm F1.4)

This is the earlier version that lacked the multi-coated optics of the S-M-C and SMC models. It is a good lens. Use it and enjoy!

Steve

P.S. The yellow is the reflection from the coating. The thorium glass versions with the yellowed cementing appear yellow when you look through them.

CWyatt · 08-24-2009, 09:54 PM

Thanks very much, I wasn't sure that this was the same lens as the database one due to the version differences,

Just1MoreDave · 08-24-2009, 10:21 PM

Here are some examples of the reflection color I was talking about, on a Super-Takumar 135mm f2.5. The huge front element and flat rear element on this lens make the reflections obvious. As you can see from the third photo, the lens itself doesn't tint the image much, while a lens with the decay issue would.