I'm a "prosumer" photographer, and until now, most of my work has been landscapes. Recently I wanted to branch into portraiture and whilst most of my glass is from Canon's "L" series, there was no way I was going to hand over £1K+ for the L series 50mm prime lens, for an area I'm only dipping my toe into.
I was lucky enough to have a kind friend to let me try out his EF 50mm 1.8 MK II (the predecessor to the STM version of this lens) and I was pretty impressed with it, although the build quality of that pervious version leaves a lot to be desired (all plastic including lens mount and the focus drive is clunky, noisy and a bit hit and miss).
This new STM version though, is nothing short of superb value for money!! Using the centre-only focus point on my Canon 77D, I was able to capture beautifully sharp images, time and time again. The focus is smooth, quiet and most important accurate and although not quite as rapid as the USM focus mechanism, still more than adequate and impressive for a lens of this budget. The bokeh on this new version is also lovely and circular, thanks to an additional 2 aperture blades compared to the previous version.
It does suffer from a little CA and fringing in areas of high contrast (backlit detail near the edges of frame for example) but even my L glass exhibits this and with Canon's Digital Photo Professional 4 software (or the appropriate lens profile uploaded to the camera), this can be well controlled.
I've seen good reviews of the cheaper, Chinese brands that compare with this lens and I'm sure they can produce good results. But for me, I prefer to stick to a brand I know and trust, and generally I've been happy with Canon lenses and did not want to diverge from the brand. I'm glad I didn't as this new version of an already great value lens ticks all the boxes, and for me, solves all the shortcomings of the previous MKII version.
With the exception of focus speed, I also think the STM focus drive has almost all of the advantages of the USM mechanism, hence why I didn't consider the more-than-twice-the-price 1.4 50mm USM from Canon, which seems to get mixed reviews.
The focus ring on this lens is fully electronic, which means there is absolutely no mechanical connection between the focus ring and the focus drive mechanism. Instead, the ring sends a proportional focus control signal to the camera body, which then in turn proportionally drives the auto focus gear in accordance with the ring movement. This makes the focus ring beautifully smooth, seamless and continuous, and also means it can be complete disabled in the camera software (assuming your body supports turning off manual focus override) which means you cannot bump the focus whilst handling the lens during shooting.
If like me, you want a lens to take beautiful portraits with, I can only sing this lens's praises. As the cheapest lens I own, it also now ranks as one of my favourites and it's very easy to forget how inexpensive this lens is, when you see the quality of images it can produce!