Did anyone ever try this combo?
I've just bought a 70-300mm macro that would become a 210mm-900mm using a 2x teleconverter over the the LA-EA1. One thing is for sure...this would probably be one tough combo to test your manual focusing skills.
Yes, 900mm is tripod only. With the help of magnification and focus peaking it might be doable; but I don't know if you'll be pleased with the IQ. My experience with 2x converters is disappointing. I only use 1.4x.