Its an older EF lens and soft in the corners I know. But will it work with an R5?
I shoot video and wide angles when traveling and sight seeing.
The 17-40L might be ok for 4k and lower resolution video, but it will be pretty soft on the R5 for photography or 8k video.
I have both lens. The 17-40 is a lot more economical, but honestly not as good as the 14-35 in many area
Not only is the 14-35 much sharper with better contrast and less chromatic abberation, its focusing speed is more than two times faster, quieter to operate with better image stabilization, shorter focus distance, higher magnification and slightly bigger zoom ratio.
14mm is obviously a lot wider (20+%) than 17mm
17-40 has 5mm longer reach, but image from 14-35 at 35mm enlarged to 40mm would show more details than the 17-40mm at 40mm on a R5