Sigma 16mm f/1.4 or just keep the Canon 22mm f/2

I have extensively tried both the Canon 22mm f2 and the Sigma 16mm f1.4 at night for extreme low-light photography, in conjunction with DxO Photolab and its DeepPRIME de-noise.

The 22mm f2 is a great lens because it is 'very good' optically, and so small and light. it gives sharp images in the daytime and is so small it fits in the camera bag without a second thought.

I do railroad photography and video, and what I've found is that the Sigma 16mm f1.4 lens is optically a class above the Canon 22mm f2 lens. It has much better flare control and gives cleaner, contrastier images in very low light than the Canon 22mm f2 lens.

My videos shot with the 22mm in very low light are washed out enough (poor contrast) to be unusable, where the 16mm f1.4 results look great. The Sigma 56mm f1.4 is in the same class as the 16mm f1.4, and the Canon 32mm f1.4 is even a cut above those two due to its incredible sharpness wide open.

I am currently experimenting with the Sigma Contemporary (EF) 150-600mm f5-6.3 extreme telephoto lens, for more reach beyond the EF-M 55-200 and EF-S 55-250 IS STM lenses. I"m comparing them all, and unsurprisingly, it's looking like the Sigma is optically superior to the Canon kit telephoto zooms when used at the same focal lengths. It is really large, quite a beast of a lens, though --- not a lens that's going to be carried around regularly!

With Sigma, it looks like optical quality is a very high priority, and the 16mm f1.4 lens is larger and heavier so that the optical quality will be uncompromised.

On my recent vacation, when walking at night in the city, I did carry the M6ii with no EVF and the 22mm f2 on a strap around my neck, inside my jacket. This way it didn't look like I had a camera, but I had it when needed, and the 22 is good enough to shoot city scenes in well lit areas at night. So there definitely is a place for both lenses for me.

The other 'great' wide night lenses I use are the Rokinon 12mm f2 and Laowa 9mm f2.8 lens. Both are also excellent low light lenses in the same class as the Siggy 16, quite sharp wide open. They are manual focus lenses, but at that wide a focal length, you can reliably set focus using the focus scale much of the time, plus they have a deep depth of field, and because they are so wide you can use slightly slower shutter speeds, making them as useful as the Siggy 16. The Rokinon 12mm f2 in particular is a fairly inexpensive lens compared to the other fast, wide options.