[Paleo Pete]

LOL...

[rawr]

I didn't need another 50mm, I had 5 already...

I think Digitalis holds the PF record for the most 50mm's - he has said he has over 50 of them (presumably from various manufacturers aside from Pentax).

I only have 3 50mm's - the M50 1.7, a Ricoh XR Rikenon 50 f1.7, and the FA 50 1.4.
I feel so inadequate .

[stevebrot]

I have a ton of fast 50s and I can honestly say that the M 50/1.7 is the best performance value in the Pentax line. In 1978, Modern Photography used the Pentax-M 50/1.7 (along with the Leitz Summicron 50/2 and a rogue's gallery of fast 50s from various makers) in their test for ultimate film resolution (target = 100 line/mm). Read about it here:

How Sharp Can You Get? | Flickr - Photo Sharing!
How Sharp Can You Get - continued | Flickr - Photo Sharing!

(Thank you Nesster (Jussi) for the scans!)

Hint...The Pentax-M did very well. Another note...lenses faster than f/1.7 were conspicuously absent from the test. Modern noted during their testing over the years that the faster f/1.4 and f/1.2 optics were less sharp overall than their slightly slower brethren.


Steve

[Jean Poitiers]

I think Digitalis holds the PF record for the most 50mm's - he has said he has over 50 of them...LL.

He once wrote that the total number was 180 .... J

[Jon]

Love the M 50/1.7 as well. I got mine on an MX a while back. I used it as my sole lens while walking around Boston this past week. Plenty of b&w streets shots of it Here

[Paleo Pete]

I took mine out for a walk yesterday, thought I'd show off a couple of shots of what this baby will do.







Tried a couple of shots wide open but as usual didn't like them, these were all at f8. This is a really good lens, but as I said, my favorite is still the A series f1.4.

[whojammyflip]

Another note...lenses faster than f/1.7 were conspicuously absent from the test. Modern noted during their testing over the years that the faster f/1.4 and f/1.2 optics were less sharp overall than their slightly slower brethren.

Speaking personally, for my two 50's, M 50/1.7 and M 50/1.4, the 1.4 is noticeably better, at f5.6, when shooting test charts, by a clear grouping, or 12%. This will of course be sample dependent, and with the 50/1.4 having been more expensive, its likely to have seen a better life, but my M 50/1.7 is also in good condition. Its similar in the difference between the 28/2.8 and 28/3.5 in my opinion: nice to know its there, but unless you are shooting with a tripod, its not going to make a difference.

For what its worth, both 50's were substantially sharper than a 50mm 1.8 MIJ OM Zuiko. I only tested f5.6, f8 and f11, and the M 50/1.4 appears to be diffraction limited at f5.6, whereas the M 50/1.7 is not.

[stevebrot]

Speaking personally, for my two 50's, M 50/1.7 and M 50/1.4, the 1.4 is noticeably better, at f5.6, when shooting test charts, by a clear grouping, or 12%.

Have you seen @LesDMess' comparison tests? His M50/1.7 and M50/1.4 were pretty comparable at f/4 and f/5.6 with the 50/1.7 being somewhat better at wider and narrower apertures. (LINK)


Steve

[whojammyflip]

I havent looked I am afraid and I have one of those internet blocking things which I need to switch off in order to take a look at the link you sent.

The difference I saw was small but definitely there. The other thing that may explain the difference could be the different interaction of the lens and sensor design. Nevertheless, on film at least, the difference is there, albeit small. Next time, I will test from f2.8 through to f11.

I actually just bought a 2x magnifier for this kind of testing, to double check the focus is spot on. I am using a MX which I had serviced for focus etc by Harrow Technical, so the camera is in tip top shape. The comment about the tripod is particularly relevant: without everything being set up to achieve the best from the lens, I don't believe that the difference between lenses will be detectable.

However, all the above said, I thought that I would wade in with the counter-common opinion that the slower lens is sharper: for my two M lenses, this is definitely not the case.