@BurnetRhoades

That's not spin. It actually makes the lens faster

Yes - I realised that - just saying, I like the way they chose to use that description over the focal reducer one. I've followed the similar topic on here for a long while and it became apparent that making a focal reducer is quite difficult to do well, and it looks like they've succeeded very impressively. A lot of money but the video examples look great. For me the ability to use the whole (mostly, anyway in MFT) of a standard DSLR lens image circle brings about lots of advantages and I hope they have great success with this product.

@BurnetRhoades And then there's the question of how to adapt different lenses to the Speed Booster - because I'm sure most people have a range of different lenses.

@itimjim

Why would I want to adapt from EF? What you've suggested adds to the problem, not solve it. Now i would have to buy additional adaptors to faciliate the EF mount. So what, CY to EF? Minolta to EF? Pentax to EF? Just so i can in turn slap glass of different mounts on the metabones? Where does this madness stop? Goes back to my initial point - how much do you need to spend to make this work?

@kazuo The way I see it, is you have two choices. You buy a Metabone Speedbooster for each lens type one has, so mFT > EF, mFT > Nikon, mFT > whatever is available at $400-600 a pop. Or, you buy one Speedbooster adapter and then adapt to the front mount....which is going to be a lot cheaper.

So then one has to choose the front mount. In my case, that's Nikon, but if I had EF lenses and Nikon, I would choose EF and buy an EF to Nikon adapter. Cheaper than buying two metabones adapters.

One thing is for certain, is there will not be a mFT read > mFT front version.

@Kronstadt read the pdf whitepaper. It clearly shows DX/APS-C type lenses being compatible with mFT or smaller sensor (BMCC for instance). However, the Sigma 8-16 will not work with the Speedbooster on APS-C sensors. If Metabones release an active mFT to EF remains to be seen, so the 8-16 may never work regardless.

Usually EF lenses retain good resale value. Also good value for the money. One could use them on Canon DSLR for photography and on Gh1/2/3 for videography. Some, I guess most of them, use mechanical focus/zoom rings. The only zoom I have is 14-140, and I may get the speed booster if it's proven to work well. I got friends loaded with Canon L lenses collecting nothing but dust :)

But this won't replace native m43 lenses like 12mm T1.6, 17.5mm 0.95, and 25mm 0.95. The native lenses have advantage in minimum focus distance.

Designers share some thoughts on m43 adapter: http://diglloyd.com/blog/2013/20130114_6-Metabones-Speed-Booster-Caldwell.html

They say the IQ might be better than the NEX.

I just got samyang 24mm t1.5 and 14mm t3.1 cine lenses. canon mount with eos-m4/3 adapter for my gh2. will I benefit from this speed booster adapter?

@lenuisible Yes, of course, I doubt that m4/3 have a circle large enough--although I guess one could use them in etc mode for yet another look. Even if I could only use it in my my 50/1.4 it would be a good investment, and I'm sure the Nikkor 85/2 would get some use. Obviously newer prime lenses that are sharp wide open would be amazing, but some of these would have to be jiggered for aperture control if they aren't full manual.

Curious what the effect of ETC mode mode would be, if it is possible.

So what are the super hot lenses for this adapter? Obviously any 50/1.4 is going to be a low light winner, and inexpensive. Are there any lenses we should look at in particular before the price goes up on eBay?

@DrDave I heard Samyang will release 50mm CINE T/1.5 lens this year. Yeap 35mm T1.1 equivalent :)

APS-C f/2.8 zooms for m43. FF f/4.0 zooms for NEX.

Will this work on a GH1 or will it only work on the GH2 and 3. I believe the sensor sizes are a bit larger on the 2 and 3?

@stonebat Good starter list, I'm especially interested in primes that are sharp wide open that then become "super primes", like sharp F/1.0 that really don't even exist right now. Many of the old primes are good value but really have to be stopped down. Obviously, some of the newer prime lenses are sharp wide open, so it is interesting to ask what is the best value for primes that are sharp wide open, have no circle/focusing issues and also work with filters, have good bokeh, and so on.

What would be the best bang for the buck for a "super prime" in each range? It seems like the Samyang 85mm, though heavy, would be a good candidate for super prime status.

It'd be a major boost to use it with CP2s on m4/3 and BMCC cams. I'm looking forward to trying one out.