$270 Bargain

I bought this lens for the equivalence of around 270 USD, it was more or less like new. I could have bought the Tamron or Sigma 45/50mm lenses but they are over double the price and don't look like they offer double the IQ! I had owned the 50mm 1.4 Art before and wasn't impressed by it for the size and weight of the thing.

This 50mm weighs around 500g and is quite fat but it's not as big as the f/2.8 zoom lens sized Art version. I generally use my Tamron 24-70 so that's another reason why I didn't want to pay close to $1000 USD for a lens that won't be my primary.

I find the wide open IQ to be quite good, it's at least on par with my old Nikon 50mm f/1.8G, once you stop it down to f/1.8 and beyond it gets very sharp in the center, corners need closing down more, but I bought this lens for strong large aperture performance.

Autofocus is stellar, the motor has a bit of a kick to it but it's quiet and accurate. I added around +3 for my D750's fine AF tuning and that has corrected the slight autofocus hiccups I was having. I had a Nikkor 1.8G that required +12, so good job Sigma!

The bokeh is the best thing about the lens, it's quite outstanding and nowhere near as harsh as my Nikkor 50mm 1/8G or Tamron 24-70. Backgrounds melt away with ease.

Distortion, CA, flaring hasn't been an issue for me. There's definitely CA if you don't correct for it but this is true for many lenses. I'm enjoying this lens for its large aperture performance at a very appealing price. There is an issue of colour fringing wide open but this can be corrected with some Lightroom editing, it does not bother me much though as I won't notice it unless peeping.

I hear Canon versions have more AF issues but for Nikon I highly recommend it.

EDIT: This lens will not focus in live view on my D750, I'm personally OK with this but I docked half a star for the inconvenience and wide open fringing.