@Vitaliy_Kiselev is there any word for a 43 to m43 adapter?

Few are available at

http://www.ebay.com/itm/Metabones-Canon-EF-to-Sony-NEX-Smart-Adapter-with-Speed-Booster-NEX7-NEX6-FS700-/221181644952

@B3Guy

Yes, the MSB increase the lens light by one fstop, it is true. What it does is to project the same amount of light to a smaller area, so it will be brighter.

To understand it you can do a test with a projector in the wall. For the same lens setting and same light power in the projector, the image will be brighter if you project a small image and it will be darker if you project a big image.

This is the principle of MSB, take the light from the lens and concentrate it to a smaller area, so it get brighter. It is the opposite of a teleconverter, which increase the area of projected light, so you get a darker image in the sensor.

Same amount of light to fill a small area will be brighter than same amount of light to fill a big area.

If you can use a faster shutter speed and achieve the same exposure, the lens is faster.

B3Guy, adapting lenses is more complicated than just comparing the flange focal distances. It really comes down to the shape of the specific lens and camera and whether there is room for the lens and an adapter. Sometimes you can adapt a lens with a shorter flange focal distance, e.g. C-mount to m43. Sometimes you can't adapt a longer flange focal distance format if the lens has parts that stick out too far past the flange - for example, PL mount to Nikon F.

@Shaveblog , this adapter have optics between lens and sensor ... something very different ...

Just wishful thinking, but is it possible, if eventually someone were to make a modular version, to have part of the system be an iris plate, like a back end filter, that had for example perfectly round bokeh as well, or different shapes.

I'm totally sold on this, but I guess I will wait for the M4/3 version, or buy a Sony, those seem to be my choices. Very curious what a medium format lens plus adapter plus metabones would do. Hope I don't have to mod the mounts on all my Rokkors.

Roger Cicala's explanation was cogent, thanks for the link. For the non-believers, it makes the most sense to speak in terms of a reverse teleconverter; for those of us coming from film, we intuitively understand that we lose a stop or two with the TC, so the reverse seems at least plausible.

Very impressed with the Samyang 24mm F1.4, I mean, holy cow. Porca Vacca.

Actual MTF figures (preliminary; it's still early): Cicala's MTF figures indicate a 22 percent increase in resolution using the adapter; that is, 590 jumps to 720. At f/0.9, it resolved 720 lp / ih. Oink! Obviously, that Canon F/1,2 would be a nice investment, but maybe a good 50/F1.4 would be almost as good.

I remember when m4/3 came along, a lot of junk lesnes suddenly shot up in price. I waslucky enough to get my Vivitar 55mm macro for $13, but now they are not cheap. We can all cry in our beer about missed opportunities. I'm just wondering if there are some lenses that we should try to grab. For example, is a Hasselblad 85mm medium format going to be be a monster lens? Maybe someone who is good with crunching the numbers can speculate a bit. It could be the more recent lenses work better.

If you buy a Alpa to MFT, and some cheap adaptors Nikon - Alpa, Minolta - Alpa and Canon FD -Alpa, you get a modular adaptor ready for all situations. (I'm trying to get someone that makes these adapters for Alpa.)

@Blackspot it would probably have electronic iris support like the EF-NEX adapter does.

Another review from RogerCicala from Lens Rentals - but for photos only:

http://www.lensrentals.com/blog/2013/01/metabones-magic

He liked it.

I saw the review and to my eyes we do not need to worry about the corner softness. It is more pronounced in 100% magnification for High Megapixel still photos. For 1920x1080 videos the corners get pretty good even at 100% magnification and wide open. Stop down the lens one fstop is a rule for me to get better quality and this improves corner sharpness a lot more with the MSB. Also the M43 sensor crops more than the NEX sensor, so corner softness will be lower. No worries for me.

@B3Guy I think if you put a lens on, as several have done, and it meters at F1.2 instead of F1.4, then it is faster. Faster means it meters faster, because you are actually measuring the light. I think the physics is going to take a while to sort out, but ultimately, if it meters faster and IQ looks better, that will be good enough for most people.

@Brunoalmeida I intend on doing this. i don't need electronic control of ef lenses, nor do I use Alpa lenses. I will buy an alpa speed booster and probably fashion some type of flat metal adaptor to replace the alpa bayonet. since there is infinity focus adjustment built into the speed booster I will aim to get as close tolerances as possible and have the infinity calibration to tweek it to perfect. the simplest option would be to take the front flange off whatever cheap dumb adaptor you need to use and use a thickness of machined aluminium to make up the extra distance.

it'll be a nice few hours project and I'll save $200 off the ef version