With an R to E adapter in hand, I had a chance to test the venerable 180mm APO-Elmarit-R and APO-Extender-R 2X directly against the E 70-350mm G lens. On moderately fine details, shooting both at f/8, I could see no difference in either edge acuity or color. And with the G lens less than half the weight of the R combo, and with AF to boot, the choice of which to carry is an easy one.
Interestingly, though, the a6700’s focus magnification starts at 6.1X and I can find no way to customize it in the way that some m43 bodies permit. I can only guess the choice was (correctly) based on the notion that very few people shoot long with MF, and the high magnification is useful for focusing on things like eyelashes.
Then there’s the matter of whether half-press of the shutter button deactivates magnification or not. Shooting critters, the preference is to keep the subject area magnified until after the shutter fires, which the Sony does. But with shorter glass, using portraiture as an example, one would either need to set the focus point over the eye of choice before magnifiying, or else double push the button used for magnification in order to return to the full image, presumably to compose the shot, before pressing the shutter button.
Fair enough that Sony chose to keep using their excellent 2.4mp EVF in the a6700. But I have to wonder why they put it in the a7CR. It’s one of two things: lack of space for a larger EVF in the body design; or perhaps a plan to include a higher-mp EVF in the future, to help nudge people towards the a7CR II whenever it comes out.
Either way, I think—after putting some thought into it—that the a7CR will be a more suitable addition to the kit than would an a7RV. The EVF in the latter is overkill for my eyes, especially since I’ll likely be using mostly AF going forward. And I don’t really need the 1/8000 mechanical shutter. The centered EVF would be useful for a lefty like me, but I’ve grown so accustomed to pressing my nose against monitors over the years that it’s probably flattened some anyway.
Experimentation continues as weather permits, though daily highs in the upper 90’s without cloud cover have force me to remain indoors more than I would like. Seems like I went very quickly from 30’s, 40’s, and steady rain to 97-98F and blue skies, without any middle ground. And as soon as the heat ends here, the monsoon season will arrive—by which time I will hopefully be elsewhere, probably still complaining about weather!

a6700/ZA 55mm f1.8 . . .