So I have a hunch… and as previously mentioned it’s the right time to speculate since all of the imaging shows are coming up.
As you know, Sony is producing a 400mm f/2.8 G Master lens…
And as you might not know… the Sony E mount extenders are currently only compatible with two lenses.
The FE 70-200mm f/2.8 GM OSS and the FE 100-400mm f/4.5-5.6 GM OSS lenses are both compatible and have been specifically built with a large enough recess in the lens to allow the extenders to be attached.
The only other lens people really thought might be compatible was the Sony 70-200mm f/4. It isn’t compatible with either extender. It seems that the recess is not large enough to even fit the optics protruding from the end.
Almost all of Canon’s and Nikon’s long telephoto lenses are compatible with their extenders… it’s just how things work when you get up there in focal length.
It only makes sense that the 400mm G Master lens will also be built with a recess that makes it compatible with the Sony E mount extenders…
The extenders will allow you to have an 800mm f/5.6 lens with the 2x extender or an 560mm f/4 lens with the 1.4x extender on full frame cameras…
For APS-C cameras the lens would become a 1200mm with the 2x extender and an 840mm lens with the 1.4x extender.
So that’s something we have to look forward too. It’ll be nice to have Sony extenders that have real utility and aren’t only accessories for two specific lenses.