[Henrico]

During the years buying lenses and cameras on Marketplace I collected some standard lenses as colateral damage… . This afternoon I had nothing to do so the ideal moment to compare them on 36 MP on center sharpness, corner sharpness and bokeh.

The wariors:





The M1.4 is my original, I bought this in the late 70-ies as kit lens on my ME-super. In the days of film my best results were shooting at F2.0 for nice bokeh and acceptable sharpness, and at F5.6 for tack sharp images. Shooting wide open was tricky, I always was very keen on precise focussing using my split screen, so I suspect the film was not always flat on the slider or the distance to film and mattglass was not exactly the same.

On the K1ii focussing is much more precise. Test scene again is my backyard on a sunny day. I focussed on the outer leaves of my oleander and checked the focus with live view. The DFA kit lens was the benchmark.



The test scene: (M1.4 wide open)



Center sharpness at F2.0:




Corner sharpness at F2.0: (I focussed right in the center with focus confirmation and turned my camera so the opbject moved to the right upper corner)




Bokeh at F2.0:




Center sharpness at F5.6:




My overall conclusion:

M1.7 is the best, A1.7 is very similar. A little bit CA around highlights. M1.7 is beautifull constructed, the A1.7 feels plastic with a horible aperture ring. Only usable in A-mode.
M1.4 is very good either, only corner sharpness at F2.0 stays a little bit behind the 1.7. You have a bonus for 1.4 for extra less DOF and extra dreamy bokeh. With live view focussing is very reliable nowadays. Beautiful lens even after 40 years of service.
M2.0 is the weaker one. Less sharpness at F2.0 but also at F5.6. At 2.0 it is ghosting in the far corners. It also clearly has a different coating than the others and one lens element less. This is a budget lens.
K1.8 is not as crisp as the 1.7 and 1.4 are, but decent sharp and good corner sharpness too. Almost no CA at F2.0. This lens is build like a tank and still working fine despite it is the oldest of all.
Bokeh is very similar at F2.0.
All these lenses have the advantage of a larger aperture so you can isolate your objects. The kit lens starts at F4.5 at 50mm.
Compared at F5.6 all lenses perform equal with the kit lens at F5.6, only the M2.0 still stays behind a little bit even then.


Cheers!

[pschlute]

Nice test and write up. The M 50mm 1.7 was the first lens I ever owned. It is a great performer and works as well today as it did when I first bought it 40 years ago

[ZombieArmy]

The m 50 1.7 is by far my favorite M lens. It's such a good performer, and has a great look. Treat to use too.

For some reason all the A series equiv lenses I've used have disappointed. I did a similar test with the Tak 50 1.4 vs the A 50 1.4 and it was really obvious the tak was better. I wonder if QA slipped during the time of the A series?

[WPRESTO]

Various versions of the f1.7 have generally been considered the sharpest of Pentax normal-focal-length primes, with various versions of the f1.4 sacrificing a little resolution for getting the wider aperture. The f2 was always the bargain normal prime, although a decent performer.