R5 lunar photography with stacked EF extenders

Bigger wrote:

J.K.T. wrote:

Bigger wrote:

Yes, with the control ring. All 8 pins seem to have independent springs, and the force seems comparable to Canon lenses (but I didn't attempt to measure this). The adjacent pins didn't move.

OK - then it better than mine. As it seems also easier to mod (less material to remove), I'll have to get one of those. Disassembly is likely not an option, though.

I also have the Commlite CM-EF-EOS R, but I can't find it at the moment. If I locate it, I'll check it and report back later.

That would be nice - thanks!

I found the Commlite CM-EF-EOS R, but it doesn't behave as you describe. All 8 pins seem to work independently.

Here's a pic of both, with the modified Commlite CM-EF-EOSR ARC on the right:

Commlite CM-EF-EOS R (left) and Commlite CM-EF-EOSR ARC with casting ridge filed down to fit RF 1.4x (right).

You can see that the standard adapter would need major surgery to fit the RF 1.4x, but the ARC version only needed minor mods.

And here is the finished product:

Modified Commlite CM-EF-EOSR ARC mated with RF 1.4x.

This can fit any EF lens now. I've mated it with the EF 24-105 f/4L II and EF 100mm f/2 and it seems to work OK. But like with the TC stack, the R5 reports the RF 1.4x, but it doesn't multiply the FL by 1.4x:

Sample image with R5 + EF100mm f/2 USM + EXTENDER RF1.4x. Note R5 still reports FL as 100mm.

Very nice! I've taken optics out of good MC7 vintage Kiron teleconverters and mounted them into digital EF extension tubes, to make Canon EF non-reporting TCs:

https://www.dpreview.com/forums/post/64824180

I've also found that a Kenko Canon AF (EF) C-AF Teleplus SHQ 1.5x teleconverter, which has 5 elements instead of the usual 4, works extremely well with the Canon EF-S 55-250 IS STM, with the teleconverter's electronics removed to make it pass-through electronics:

https://www.dpreview.com/forums/post/65293237

The teleconverters are transparent to the camera, they just report the lens mounted on the teleconverters, even when stacked. Everything works including autofocus and image stabilization. The Kenko SHQ is optically very good with very little change in sharpness or CA. The Canon M6ii seems to be able to work with the TCs down to about f16 or so, it has very good low-light performance, however diffraction starts to noticeably degrade images by f11.