Patent: Canon RF mount Big White Lenses


CR Pro
Nov 8, 2011
That's exactly what I said.

In case you missed it: The total lens length figure in the patents is not the physical length of the lenses - instead, it includes the flange distance of 20 mm. So that has to be substracted in order to get what you call the real lens length. But since you can't mount an RF lens to an EF body, the only relevant comparison is when both are mounted to an RF body - so you have to add the 24 mm adapter length to the EF lenses real length. It is not a one or the other consideration.
OK! In that case both are equal:

29.25cm -2cm +R5 depth = 27.25 cm + R5 depth


24.8 + 2.4 + R5 depth = 27.20cm + R5 depth

Same total length. I guess unless some DO technology is involved we cannot get length savings.


Wildlife Shooter
Aug 8, 2018
Interesting that they all are listed as longer than the EF mount versions?

I'm guessing that the design for telephoto lenses stays pretty similar except that they basically have a built in RF adapter to bridge the extra backfocus, but I'm sure there's not much Canon can do about that in those designs
So, I wonder if there is any way Canon could do a collapsible lens design to use all that empty space? The problem would be the size of the front element AND reliability for pro shooters. The RF 600/ 800 ARE PRETTY MUCH THE SAME DIAMETER FOR THE ENTIRE LENS WITH A MUCH SMALL ER FRONT ELEMENT. Where are the DO’s?