They've put the zoom ring—the most imporant of the three rings—in the wrong place again, as with the 70-200 f/4. You always want the most important control to be as far forward on the lens as possible for maximum stability. Putting the zoom ring to the rear means most of the lens' weight in use is going unsupported, hanging free several inches away. Even with lens IS, that's not good. At the very minimum it puts more wear on the extension mechanicism when the forward weight isn't supported. I suppose if you know you're only going to be using it at 400mm (which I expect many people will) then you could just leave it there and keep your hand on the control ring, but even then it still seems erroneous to place the zoom ring so far away from the control ring.
Also confused as to why they didn't combine the control and manual focus rings. Seems like an obvious, easy cost saving and streamlines the operation of a lens like this which is so very rarely going to be focused manually.
But still, appears to be a good size, I'm happy to see them vaguely (between this, the 24-105 f/7.1, 85mm f/2 and 100mm f/2.8) adopting the modern standard 67mm filter size, and while I don't expect the optics to be anything special, just hitting 400mm (probably actually 380-390mm) at a price below what second hand 400mm f/5.6Ls cost, and presumably a weight far below that lens (not that the L lens is particularly heavy to begin with) is a good combination. With the close focus, I can see this lens plus the 800mm f/11 becoming 'the' combo for the wildlife amateur who wants to shoot
everything from butterflies to birds and large mammels with the lightest possible kit. If an RP-size camera can be made that is just a little faster, that and this lens will be a helluva starter combination for kids.
It does raise the question of the purpose of the 600mm f/11, though, since I'm sure many people would much rather have the extra stop of f/8 than the extra 200mm, and conversely if you can live with f/11 and do value more reach then surely you'd go to the 800mm.
Should make a good landscape lens, too; I know many people think "landscape" only means 16-35s, but for my money landscape begins at 100mm.
I wasn't that fussed when the rumours started flying, but now seeing the even smaller than expected size and uncharacteristically reasonable price (unless Canon screws over the UK on the conversion again, as they've done with most RF products so far), I can see myself picking one up for the times when I'm not anticipating seeing anything special and/or I just can't be bothered to carry one of my Great Whites, moreso than I ever considered the f/11 lenses. Overcast England does not like f/11, but f/8 is right at the limit of usable.
Because the market says so. I see many people who would buy a bit higher end lenses without spending thousands on top L glass.
For example a weather sealed 85mm 1.4 which has a focus motor at least as good as the original EF 85mm 1.8 from 30 years ago.
Not the slow and noisy RF 85 F2 with external focusing. Or should we be happy the filter thread is not rotating?
Samyang/Rokinon/Bower already made the lens you're asking for. 85mm f/1.4, sealed and with a
much better focus motor than the terrible STMs (which is a motor Canon should be ashamed of, quite frankly). As a bonus, if you buy the Samyang-branded version it will even have a red ring, because sure why not. (The Samyang-branded version is actually temporarily unavailable due to their distribution problems with covid, but the Rokinon and Bower versions are still around and the Samyang will come back... eventually...)