I picked up my copy today and can give some first impressions and comparisons with my other wide angle option the RF 15-35 f/2.8
I did a little sharpness comparison on the R5. Wide open (f/1.8 on the prime vs. f/2.8 on the zoom) the lenses are pretty similar regarding sharpness in the center. In the corners the new 24mm is a bit softer tough.
Stopped down to f5.6 the prime is noticeable sharper in the middle but still a tad softer in the corners again. Not soft in general, but a bit less detailed.
Overall I would say the 24mm is a good performer (especially compared to the 15-35mm which is an awesome lens), outresolving the L lens in the middle and being not too far off in the corners.
And yes, the lens has pretty severe barrel distortion but is of course automatically corrected in camera. Lightroom also already offers the lens profile.
Chromatic aberration is definitely present, especially LoCa. Quite similar to the RF 50mm f1.2 in that regard.
The bokeh is definitely nicer on the RF 24mm – if the RF 15-35mm f/2.8 has one weakness it‘s bokeh, especially trees and leaves that can look quite harsh. But the rendering of the 24mm is definitely softer there.
The Macro ability impressed me quite a bit. You can get fairly close (around 4cm to an object) and the sharpness holds up. Only problem here is the LoCa wide open, but it is greatly reduced, once stopped down.
The sunstars are nice and pointy when positioned at an edge, but have the “double-spike” effect similar to the Rf 35mm f/1.8. Flare is absolutely no issue, there is a bit of ghosting but nothing too distracting.
Lastly the IS works nice, giving similar results as the RF 15-35mm, which means for me that I can usually hand hold around 1s.
From my first test I think it‘s a very well rounded lens. Sharp, very good close up capabilities and nice bokeh. The only downsides are the corners that are not quite as sharp and a bit of LoCa. Hope that was useful for anyone interested in this lens.