Free lunch! Free FREE LUNCH!!!I don't understand this comment.
ROFL ... hahaha!!!
What the metabones adapter does is quite sensible. The image projected by a FF SLR lens covers (for example) 4x the area of a u4/3 sensor. The adapter functions like a reverse-teleconverter, so that the entire FF image is reduced to cover the area of the smaller sensor. By all accounts (e.g. lens rentals) this works extremely well, even with the additional optic elements.
There is no "free-lunch". You are simply using all the light that the lens gathers, rather than throwing it - and the field of view - away.
While I agree in principle, the AF performance using these adapters leaves a lot to be desired. After using one on my friends camera (which was sloooooooow), I couldn't care less what IQ it delivered ... But then maybe I'm spoilt with the AF of the 5d3.
I already have an adapter that allows me to use Canon lenses for my Sony, but it cripples the AF even more... it's called an E-mount-FD adapter
5D3, 5D2, G5X, G16 | SY14/2.8, V20/3.5, 28/2.8 IS, Ʃ35/1.4, 50/1.8, 50/1.8 STM, Ʃ50/1.4 EX, 100/2.8L IS Macro, 16-35/4L IS, 24-105/4L IS, 70-200/2.8L IS II, 1.4x II, 2.0x III, T28-300 VC PZD, 70-300L IS, Ʃ150-600 OS HSM S