Canon EF lens and a TC on a Canon R

[rgs]

I have an EF70-300L. They are not supposed to work with a TC, but it seems to me that the lens and TC might work on an R6. Here's the question: Should the TC be an EF model or an R version? Would it matter? Would the addition of the EF to R converter foul up the optics in the TC?

[stever]

I think the only way this works is with the R extender on the camera and a modified converter such as a Velo filed out about 1/16th in on the bottom to clear the extender (modifying the canon converter would be a risky proposition).  I found some examples on the web, try googling something like "R5 with extender and converter"

there's a Velo converter on my desk waiting for the file

[stever]

finally got around to filing out the Velo adapter - works physically & operationally with RF lenses not designed for converters. Images look sharp enough with the RF1.4x but haven't done a resolution test or a careful comparison with the EF 1.4x on my 70-200 or 100-400 .

[rgs]

Thank you. I'll keep this in mind.

[stever]

got around to testing EF 70-200 f4 with extenders on my R5. i printed crops equivalent to 16x22 which is the largest i can prin.  the EF 1.4xiii appears to be marginally sharper than the RF 1.4x with modified converter looking at fine hair & feather detail, but it's a very small difference (there's essentially no difference between equivalent crops at 200mm with & without the EF extender - the 70-200 is making good use of all those R5 pixels.

I also tried my 2xiii - much better off cropping from the 1.4x or lens without the extender