Canon released two unique lenses with the Canon RF 800mm f/11 IS STM and RF 600mm f/11 IS STM. Here is a RF 800mm f/11 IS STM review.

Christopher Frost Photography posted their Canon RF 800mm f/11 IS STM review.

The Canon RF600mm and RF800mm F11 IS STM lenses are the first fixed focal length super-telephoto RF lenses and are incredibly compact and lightweight.
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Continue here:
https://www.canonwatch.com/canon-rf-800mm-f-11-is-stm-review-with-sample-photos/