RF24mm F1.4 L VCM

As with all the modern "really nice" wide-aperture lenses this one has VERY strong uncorrected vignetting in the corners on a full-frame camera. Corrected it disappears, of course -- this is the price of the lens being both reasonable in cost *and* mass, never mind allowing a sharper overall (corner-to-corner) image -- which this lens delivers. Stop down some and the vignetting is greatly reduced, of course. But you buy this lens for its wide aperture and thus the creative expression it allows, never mind being able to shoot in very low light (think star scape and available-light photography where the narrow depth-of-field is either acceptable or even desired.) I have both APS-C and full-frame "R" series bodies and thus I can have a modest wide (~38mm) or 24mm focal length depending on which body I use. Focus performance is excellent and this lens is tack-sharp producing very impressive image quality from corner-to-corner -- not just in the middle. Its not inexpensive but for what you get the ask is very reasonable and I'm happy to have it in my kit.

Low abberation, low coma, although some color fringing is noticeable in some situations, but is easily corrected in post. Very sharp, very lightweight. No depth of field aperture marks but ability to use DOF apps and manually focus with distance data on the screen overcomes this limitation. This lens is designed for the images to ONLY be used when lens corrections are enabled. If you disable them during post, you will see a severe amount of peripheral shading, and the barrel of the lens will clip the corners. Generally this isn’t a major issue, but for some specialty work such as nightscapes this can cause some post processing shortcomings. However, for this same type of work, the comatic aberation and astigmatism is about the lowest I’ve ever seen in a wide-angle lens with stars on the edges and corners depicted as round points of light, even when shooting wide-open. I agree with other online reviews that this is probably Canon’s best performing wide angle lens they’ve ever produced when shooting nightscapes of the Milky Way, and the performance wide open will improve nightscape exposures by at least 1 EV since you don’t have to stop it down to reduce astigmatism and coma. The AF capability wide open when shooting starry landscapes is also superb, eliminating the need to use focusing aids to achieve sharp stars. If you can achieve sufficient exposure, or don’t overly process nightscape imagery, then the lens corrections won’t be a problem. Given it’s tremendous performance on rending stars wide open, ease of focus, and light weight, this will likely be my new go to lens for Milky Way photoshoots over my very heavy, manual focus, expensive german made lenses I’ve been using for that work up to this point.