Which 50mm(ish) f/1.2?

I'm slowly working through my LBA wishlist and I've been looking around at 50mm f/1.2 lenses.

I like the 50mm focal length for doing portraits on my K-m and have a couple of F1.4s (Pentax K50/1.4 and Chinon/Tomioka 55/1.4). I'm happy with both of these, and am pretty sure I don't actually need an F1.2 (which, of course, isn't the point!) but I would definitely like to have a go with one.

I've been looking at the following:
- The Pentax options, which seem to be highly regarded but very expensive (ideally an A1.2)
- Tomioka manufactured lenses (Porst, Chinon etc.) seem more affordable, but not as good as the Pentax. I was pleasantly surprised by the performance of my Chinon 55/1.4 though.
- Breaking out the machine tools and going for something a bit more ambitious, like converting a C*non FD mount 50mm lens, as these seem comparatively cheap and well regarded and I'm not averse to having a go and have access to workshop facilities.

If the FD to PK conversion works out (and is vaguely feasible), there is a whole seam of interesting, comparatively cheap, high quality glass to try (I'd be really keen on the 85/1.2).

Any opinions/suggestions/attempts to talk me out of it would be welcome, thanks.

In all honesty I don't think converting between lens mounts like that is feasible for the DIY engineer. You're dealing with measurements which make the old "thickness of a cigarette paper" look massive. You also need to consider how much money you'll have thrown away if it doesn't work - they may be "comparatively cheap" but you're still looking at £150-£200.

I think you'll be better off saving and waiting for a genuine Pentax 50mm f1.2 if you're that keen to have one. They are still making the A version to special order IIRC?

Wow, are you my clone? I'm living in the same area as you and almost threw down the cash for three different 1.2 lenses (FD, MD, and AIS) to do the swap over for an affordable f1.2 'normal' prime.

However, something rare happened. I actually found a reasonable deal on a PK fit 55mm Porst, and it's in the mail now! Though, if you find a cheap canikonolta f1.2 lens feel free to go nuts on it. The cheapest I found was 90 euro+15 shipping for a Minolta 50mm f1.2 from Germany.

Best of luck in your hunts.

It does sound sensible to go for the Pentax option, but the following makes it sound very straightforward to convert from FD to EOS mount reversibly:

http://www.ganymeta.org/~darren/photo_f1.2_conversion.php

I know that the PK mount has a ~1.5mm difference in register distance from the EOS mount, but as I would use it as a portrait lens, I'm unlikely to need infinity focus. Besides which, I've stripped down and reassembled several Pentax and Takumar lenses in the past and these have a means of adjusting the focussing helix, which may allow some of the difference in register difference to be taken up with an adjustment. I naievely hoped taht the FD lenses have a similar mechanism.

If I could do it reversibly (and thereby not wreck a £150 lens!), I'm quite interested in the challenge, if the result is likely to be worth the effort.

whelmed - it's a small world! Glad to hear about the Porst (it's not from Germany, is it?).

I'd be interested to hear how you get on with it.

It is from Germany as well, why do you ask?

Only because I was watching it too but have bought enough lenses this month already...

I have the K 50mm 1:1.2.

I do love the lens, but I have to say that I don't use it very often. When I do, I use it wide open (why else have it?), so it exposes properly with Av, just like the SMCP-A version.

G

I have K50/1.2.
Great lens IMO. Weights as much as a brick though. But the IQ is great and manual focus just pleasure to use. Wouldn't mind A setting though....
Can't comment on other brands as I never used other 1.2 lenses