neuroanatomist said:
Facts and data rule the day. If you look at the block diagrams of the two lenses, you'll see that the space behind the rear elements of both of them is similar.
That is true, but I think you're not taking into account the different flange distance, so for an equivalent design you'd need to take 26mm off the end of the Sony layout for it to work on EF - and that is why I am saying it potentially could be done, but only at the expense of the extenders.
I am sure there are optical formulae that would allow a rear-heavy design to still work with the EF mount, but I stand by my statement that I doubt this could be done to the same level of weight reduction/weight redistribution that the new Sony 400mm does.
There are a lot of things I think Sony need to catch up on to get the pro market to pay attention, not least their poor record on weather sealing. And the Canon 400mm 2.8 remains an outstanding lens that I sorely wish I had in my arsenal.
But, as I've said before, a shorter flange distance gives more flexibility with lens design. it's not just about the light-weight compact lenses. It's about designers having new options for all designs. No design that currently performs well on the EF lens couldn't perform at least as well on a shorter flange mount, and more likely than not it could be designed better.
neuroanatomist said:
Regardless, you tell yourself whatever you need to so you can sleep at night. You have plenty of company from other forum members who also choose to ignore reality.
If I am wrong then feel free to point out my mistakes and I'm happy to listen. I certainly don't know everything. But please do so with some civility, there's no need to descend to insults.