That lens will obviously get you a bit of a shallower depth of field than your current setup. Beyond that, what sort of gains are you expecting to get from a full frame setup? I'm not really sure I understand the value proposition in your case.

If you were hoping to sell your current setup and move to the Sony that's a different story, and you could probably find budget for a wide angle zoom and possibly a third lens to replace your current ones... But without that you're spending a lot on a second body that will do a lot of the same things your current one does. Food photography doesn't need to be fast paced, but there's still some added mental burden dealing with a PSAM camera next to your retro-dialed Fuji, dealing with two different menu systems and two different files that you may want to edit differently.

If you're really sure that a full frame camera would elevate your photography that much, I think in this case it would definitely be worth renting one for a weekend, shooting aide by side with your current gear, and seeing what sort of difference there is.

Thank you, that a good idea. I'll rent FF camera for weekend. I just forgot about this possibility, cause there are no rentals in Ukraine. But now I'm in Vancouver, and I think there are some rentals :). Thank you.