The only way I can see the RF 70-200 2.8 working with a TC is if they release an alternate version of the TCs designed to work with lenses that have rear elements closer to the sensor. But I don't really imagine that happening...
The Sigma APO Teleconverter 1.4x EX DG hardly sticks beyond the mount, and Sony made teleconverters that didn't stick either.
I wasn't doubting the ability to create such a teleconverter, more just the impetus. How likely is Canon to release TWO sets of teleconverters, each compatible with different lenses?
I mean, even if you could, why would you use a TC on the lower range when all it would do is decrease image quality?
You have an interesting point. But if the subject of interest moves closer to you, there may be no time to remove the TC. I was looking for flexibility. And I found the 1.4TC to not really degrade the image quality much, as opposed to the 2X one.
There were EF teleconverters that worked with any EF lens also. I have one. The image quality is dreadful.
A) I don't know whether teleconverters that don't extend into the lens are, in general, dreadful.
B) Not having a 70-200mm f/2.8 IS that is compatible with teleconverters is a weird choice. A lens longer than 200mm will be bigger, heavier, and >4x the price of a 2x TC, and I'm not going to buy one.
I think you can assume by the fact that Canon didn't do the new TCs in a way that works with the RF 70-200 that to do so would have been an unacceptable compromise.
Not exactly. The R bodies have a brushed silver mount ring as does the rear of the 100-500 for a perfect match. The TCs don’t have this color so don’t match either.Considering the fact that the TC's are white (and the 600/800 @f11 are not) we might expect tele lenses (with wide aperture) in a white lineup. Now the only white lens is the 100-500 that would be color-matching?