Because it does...
You used what is regarded as the softest FE lens and tried it for like 2 days before saying it was worthless and continuing to bash it on the internet. I'm sorry your buyers remorse is so heavy that you still can't let it go, but any issues you had with the system are your fault for not doing the research before you bought it.
Also, why on earth would you buy the a7 and not the a7R based on what you shoot? They're like $300 apart from each other...
Im sorry but there is no excuse for a t5i with a KIT lens to produce better images than an A7 with an $1100 Zeiss lens period. No buyers remorse at all, loving my 6D I got when I returned the A7! Where are you seeing the A7 and A7r within $300 of each other? Try $800. If it were only $300, I would have bought the A7r.


