When I bought my Sony A7 over a year ago I planned on putting lots of vintage lenses on it because, obviously, that would be awesome. I had all the classics from Leica, Zeiss and Voigtländer in mind. Only I did not have any money for a long time. So no lenses for me.
For casual / daily / street use I love the angle of view of a 35 mm on full frame (Leica, Zeiss and Voigtländer all have great offerings in that focal length), and also a large opening to have the tiniest depth of field possible. My friend Bas Stubert happened to have a Pentax K 50 mm f/1.2 in his mouthwatering photography gear collection which he lent to me, and I managed to muster the money for a measly adapter. I wanted to try if working with a manual f/1.2 lens on the A7 is pleasant enough to start saving for something more expensive (than just the adapter) in the 35 mm range.
This review of the Pentax K-mount 50 mm f/1.2 is not technical, just an account of how delightful (or frustrating) the lens is when you use it, and how awesome (or not) the resulting photographs.
To start with delightful: this 50 mm f/1.2 was made by Pentax some 50 years ago and it still works perfectly. The focus ring is quite smooth not giving much resistance but just enough, and consistent over its entire range. Also: it turns the right way, I find it intuitive (apparently, what do I know, it does not appear to be rational…) when turning counter-clockwise focuses towards infinity. The lens is small and light, with the adapter it fits tightly on the A7 and balances well. There is the tinyest amount of play when you go look for it, but while using the combination I quickly forgot about it. It does not hinder focusing, nor does it affect sharpness that I can see. The only thing that was slightly discomforting to me was the angle of view, generally I found it too tight, which is of course because the focal distance is 50 mm and not a flaw of this lens as such.
While focusing with this manual lens the A7 will not enlarge automatically, so I used focus peaking. I had already switched to focus peaking earlier because waiting for the enlargement with the dedicated Sony kit lens sometimes took longer than I cared for and that would do nothing good for my stress levels. The focus peaking takes some getting used to, learning to interpret the signs. Especially when your depth of field is not so small, you need to pay attention to the range where the Sony thinks your image is sharp, focusing a bit to and fro to assess the situation. But with a 50 mm f/1.2 it is much clearer and the peaking function works fine. Depending on available contrast you may still have to move about a little. I had some misses but not more than with a normal ground glass. Even though I still prefer the calm view of a real ground glass (like the one on my ex EOS 1Ds or soon to be ex Mamiya 645 AFD III) over the slightly stuttering electronic viewfinder, beggars can’t be choosers.
The optical quality is as to be expected. Not tack sharp at f/1.2 and some vignetting and major corner degradation going on, also: field curvature. But this is also the charm, part of why you want the f/1.2, and why you want to shoot it at f/1.2, all the time. This lens is not for landscapes or product shots, not even fashion (seriously, there are other tools for that), but for scènes de ménage, portraits, rainy days in woods, sunlit scenes of children playing or old folks dancing and stuff (I can’t post those shots because of privacy…).
With this lens slices of life are properly distorted to become favorite memories. The Pentax 50 mm f/1.2 lacks some of the instant coolness Zeiss lenses are known for (that can also be perceived as harsh), but makes up for it with a forgiving silky look that is quite consistent in different situations (regarding light, contrast, colour). Maybe obfuscating some details other lenses would have rendered, but in that way also lessening the pain these details can cause when you wallow in the past.
Well. Whatever. I am very pleased with the Pentax, and upon returning it to Bas, I have ordered myself a second hand Voigtländer 35 mm f/1.2 for the Sony. I figured I could finally afford it since we sold our house at an obscene profit. In the meantime, I will fondly remember the Pentax 50 mm f/1.2.