Canon RF 200-800mm F6.3-9 IS USM Lens Review by Bryan Carnathan...

[JFG]

Hey everyone, I have been on the fence deciding whether or not to purchase the new RF 200-800mm F6.3-9 IS USM Lens, or the RF 100-500 and Tronhard posted a thread here titled "Which is Which",  where he compares the two in a picture comparison, which I thought was great.  It made me lean towards purchasing the RF 200-800.  However, the "narrow apertures" of the RF 200-800 made me hesitate a bit.   So, I decided to research it further.  My concerns were that with such narrow apertures the lens wouldn't perform in cloudy, overcast days, and at dawn or dusk.  So, in my research after going through various reviews, I came across this review by Bryan Carnathan which I found to be so thorough that it would help others that are on the fence like me.  I'm no longer on the fence as the aforementioned review answered all the questions in depth with graphs, picture comparisons and data.  Not to mention the reasons why this lens is different from the RF L series and does not have the L series Red Ring. To give you an example of his review here is one of his illustrations.  

 "Here are focal length ranges reported by the RF 200-800mm F6.3-9 IS USM Lens in 1/3 stop apertures.

200-267mm = f/6.3
268-454mm = f/7.1
455-636mm = f/8.0
637-800mm = f/9.0

For reference, here are the RF 100-500's reported apertures:

100-150mm = f/4.5
151-253mm = f/5.0
254-362mm = f/5.6
363-471mm = f/6.3
472-500mm = f/7.1

While f/9 on the 200-800's long end sounds especially narrow, the difference at the RF 100-500's equivalent focal lengths is not so big, mostly 1/3 or 2/3 of a stop. F/9 is 2/3 stop wider than availed in the RF 800mm F11, Canon's even more affordable 800mm lens. "

I recommend, that if you're on the fence like I was, take the time to read the entire review, you won't regret it.  It is very informative.  here is the link:    Canon RF 200-800mm F6.3-9 IS USM Lens Review (the-digital-picture.com)

I hope that it helps you like it helped me and let me know what you think.