R5 lunar photography with stacked EF extenders

J.K.T. wrote:

Bigger wrote:

I think the EF 1.4x iii may have slightly better IQ than the RF. Still need to do more conclusive testing.

That would be a surprise as it should be easier to design TC with shorter flange distance - or so I've read.

Yes, indeed, that's why I said I need to do more conclusive testing. The RF 1.4x actually has a larger rear element than the EF, so I expected it to work better with the R5.

No trouble with my Commlite so far, but I will keep an eye out. Thanks for the tip. Are you sure the issues were with the CM-EF-EOSR ARC and not one of the other versions?

If I understand correctly ARC is the one with control ring. Mine did not have that. Maybe they've gone cheap on the plain adapter. Could you test whether the pins have springs behind them? In mine pushing one pin takes much more force than in Canon version and the other pins move as well - not as much, but noticeably.

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.

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.