Here are some comments from using the Olympus OM 50mm f/1.8 Zuiko Auto-S lens on the Sony A7III with the K&F concept adaptor.

Like many others of my generation (and, yes, that does date me) my first lens was a 50mm f/1.8 “kit lens” that came with my SLR camera. After using the 50mm as my sole lens for a couple of years, I decided it was too restricting for what I liked to do, neither wide enough for my taste as a normal lens nor long enough for other purposes. Eventually, I settled on 35mm for my normal lens, and 100mm for when I wanted something a bit longer, especially for head-n-shoulders portraits.

Having said that, I’ve always had a 50mm lens in my operational gear collection: currently, I have a Nikon 50mm f/1.4 that I’ve mentioned previously here and here. On the other hand, I’ve not bought a 50mm equivalent lens for my GX9 (e.g. the Panasonic 25mm f1.7 Lumix G, even though it is dead cheap) and have not missed it.

The Olympus 50mm f/1.8 has sat in a drawer unused for years until I tried it recently on an A7III. It has turned out to be something of a revelation!

I’ll let the pictures speak for themselves, but here are some overall thoughts.

At f/1.8 it is sharp in the centre, but vignettes like nothing on earth. The contrast is quite low too. The bokeh is busy in comparison to modern lenses. It is by no means unusable, but, shall we say, suboptimal in relation to modern lenses.

From f/2.8 onwards, it sharpens up nicely across the field of view, and the vignetting improves. By f/4, the vignetting is under control and easily correctable in Lightroom. Although there is minor geometrical distortion, for most purposes it is unimportant and it is possible to correct it in Lightroom (but you wouldn’t be trying to make prize-winning pictures of architecture with this lens anyway!)

Between f/4 and f/11, the lens is nicely sharp and I like the overall rendering. It also does not suffer from haze when shot into the light that some of my other lenses do.

On the A7III, it is extremely easy to focus using focus peaking. Not only that, but zone/hyperfocal focusing works very well. The opening picture was taken on an evening near sunset when I was out for a walk. I looked up to see the man with the dog passing by, with the light of the setting sun illuminating the dog’s fur. If I had tried to lift the camera to my eye and focus by hand they would have left the scene. However, I had the camera set to f/8 and hyperfocal: I lifted the camera to no higher than my hip and shot one frame without thinking further. As you can see, it is in focus, and the lighting is captured nicely, as is the gesture of the dog and the man. I could not have made that picture any more quickly using a modern AF camera.

All told, I think the OM 50mm f/1.8 has the potential to be a lot of fun for street photography, providing you are happy working between f/4 and f/11. It is very small, very light, and sharp for most practical purposes. They can be had on eBay for around 1/10th the price of the new compact Sony 50mm f/2.5G lens. For fun – not for work! – I think this is a great little lens.

Update 2023005-06: see also this post on using this lens while spending a day walking in London.