I think this is a great lens for Canon RF mount cameras and I am very happy with my purchase. I had a lot of fun using it with the Canon R5, as you can see from the examples I've posted. The Canon RF600/11 in combination with the Canon R5 is not too heavy to take with you on frequent trips and it does not become a nuisance even after 1-2 hours of carrying. Most of the images I have posted with this review are stills of full screen images. The excellent optics of this lens and the 40 MP of the R5 seem to be a good match. The lens has a fixed focal length of 600mm and a fixed focal length of f/11. Although I've successfully shot at 1/125, I've found that I get my best results in daylight at around 1/500 or 1/1000, which allows the camera to set the ISO automatically. I think the smooth high ISO R5 capabilities have a big impact on the usability of this lens, especially when shooting in low sunlight. I would definitely recommend this lens to all Canon R5 owners and I would seriously consider it for all other Canon RF mount cameras.