SMC 50MM 1:2 and 1:1.7 Comparison

Hi Experts!

I see a large number of early K mount (MX type) bodies for sale on eBay with either or both of the above primes.

Other than the obvious brightness issue, is there a difference in design?

I believe the 1.7 is very sought after - more than the 1.4 ?(which I believe IS a different design).

Would very much value your insight and opinions as I don't have a bayonet prime of this length yet (using screw Super Taks 1.4 and 1.8 with an adapter presently).

Cheers

The 50mm lenses do have different characters, and I see them as follows:

f1.2 Very expensive and very high quality, equal to the best at small apertures, and having very good handling of point light sources (ideal for night shooting)

f1.4 Very high contrast at the expense of fine resolution. Ideal reportage lens.

f1.7 The best overall performance that can be abused with close up attachments, lens reversing, etc.

f2 Needs stopping down for best results, but very fine performance at f8 and smaller. A low cost version usually sold with the lower cost bodies.

Compared with the screw thread lenses, you will find that the bayonet ones reach maximum performance much quicker, maybe at f5.6-f8 as opposed to f8-f11. The character of the images is different, but they are superb examples of the lens-makers' art.

Many thanks as always John.

I'll continue my 1:1.7 quest. (Seems to be the most versatile. And if you can only have one....)

I've never seen a 1.2! (Bet George snapped 'em all up!)

Good to know that the K mounts out perform the screws!

Cheers!

One other consideration when making your choice (apart from price) is the weight.

My:-
SMCP(K)1:1.2 weighs 417 grams (including caps and filter).
SMCP-M 1:1.4 weighs 250 grams (including caps - no filter).
SMCP-A 1:1.7 weighs 193 grams (including caps and filter).
SMCP-F 1:1.7 weighs 243 grams (including caps and filter).
The 1.2 has a 52mm filter thread compared to 49mm on the other two which also might influence your decision.

The 1.2 is certainly weighty but oh so lovely.

Whichever you decide, if its a good one, you'll not be disappointed. If you need that extra bit of speed for night shots, the 1.4 is an excellent choice.