Rated 4 out of
One of the best!"The Canon 24-70/4 L IS lens is an excellent lens by just about any standard. It's main (minor) failing is that it is not quite as good as the Canon 24-70/2.8 L II. By any other standard it is a great lens. It may be that the specific lens I received is a good one it is actually better than my f/2.8 version II at focal lengths of 28, 35 and 50mm, and only slightly inferior at 24 and 70mm. (This is of course at apertures of f/4 to f/11. If you need f/2.8, you will need the f/2.8. Beyond f/11 all lenses are pretty much the same.) It is better than any other 24-70 I have used (which includes lenses by Sony/Minolta, Zeiss, and Nikon.) One word of advice: if you don't need the IS function, switch it off. IS works by de-centering certain of the lens elements. I'm sure the designers have worked hard to minimize the effects this has focus, but it does tilt the focal plane a bit. As a result one will find focus at the edges may be a bit in front or behind the focus in the image center when IS is ""on"". This is not unique to Canon it happens to some degree with all IS (or VR) lenses in my experience. Is this a good lens to use on your Canon 5DSR? In a word, Yes! I would not hesitate to recommend it for use on the 5DS or 5DSR. Is it better at 40 mm than the 40/2.8 STM? No, but you probably will not see the difference in your 30 by 40 inch prints unless you place them next to one another and examine closely. Can you use it wide open at f/4? Absolutely! Your main problem will be darkening in the extreme corners sharpness should be fine. I do see some flare when shooting into the sun."