Which is Best ? Canon RF 100-500 or Canon EF 100-400 II 1.4x extender III

[@numlock9653]

In terms of sharpness they are virtually identical, and there is likely more margin in error on production variation or user error. But I find the bokeh slightly more pleasing on the older 100-400 mkii in every example, likely due to the slightly wider aperture that is maintained further in the zoom range. If you already own a 100-400 mkii and 1.4 mkiii extender, the only reason to spend any money at all on the 100-500 is for the convenience of not having to attach and remove an extender, however you do get a slighly longer shot at 560mm with that combo. I feel like the slight reduction in weight is purely a trade off in terms of a less robust platic vs. metal contruction. Even high grade plastics degrade slightly over time especially when exposed to the elements, where the metal body may possibly take a little more abuse. Just depends on how hard you are on your gear maybe. With a massive gap in price, it really comes down to where your priorities lay. A skilled photographer with either option at their disposal will create virtually identical images.

[@incabloc]

During focus speed testing you kept switching the RF 100-500 to manual focus to turn to min or max focus making me think there’s no full time manual focus override but I found there’s a setting for “Electronic full-time MF” on the R5, R6, and R7 (available as of new firmware from early 2021 for the R5 & R6 and older lenses) that allows the old style full time manual override focus adjust most or all EF L lenses have. I’m not sure if it’s available on the R, RP or other newer bodies.

[@Technologyadvisor1]

The problem with these new cameras and lenses is the full time manual focus is by wire its coupled to the auto focus system on the rf lens the ef lens has a proper usm manual focus ring so for manual focus the ef glass is better. not saying you can not focus manually on rf but the rf lens wants to use auto focus first so their is a slight delay when you want to focus manually perhaps a firmware update has changed to be faster .