Ef lenses on MFT

rgrebby

rgrebby

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I'm thinking about getting the black magic cinema 4k. It's a micro 4 thirds system but with a speedring I could put my ef lenses on it.
What's the maths for telling what the mm would be?
 
rgrebby said:
I'm thinking about getting the black magic cinema 4k. It's a micro 4 thirds system but with a speedring I could put my ef lenses on it.
What's the maths for telling what the mm would be?
Click to expand...

Double the focal length of the lens and that gives you the 'equivalent' FOV you'd get on a full frame camera. There's different types of adapter, you can get dirt cheap 'dumb' adapters - so called because they don't send any info back to the camera, and they will be manual focus only, but image quality wise they will be perfect. You can also get AF adapters for Canon EF lenses, there's the very pricey Metabones, or third party versions like the Viltrox EF-M2 - these allow auto focus of EF lenses but they are also 'speed boosters' - They give you an extra stop of light, and a focal length multiplier of 0.71x so they become much closer to their original focal length. For example, take a 50mm 1.8 EF lens - with a dumb adapter you get a 100mm 1.8 equiv [I won't go into DOF, the aperture remains 1.8 for light gathering] - Take the same lens and use it with the speed booster adapters and you get a 70mm f/1.3 equiv so not exactly a stop, this is what speed booster users report that they get with a 1.8 lens] - they are pretty tasty because of this but also much pricier. You can get the Viltrox EF-M2 for about £140. I suggest looking more into it, I'm not the best at explaining but I've thought about getting one myself for my MFT cam.
 
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The problem of dumb adapters for EOS lenses is the complete lack of adjustability for the aperture! I have the Zhongi Lens Turbo 2 EF to M43 Speed Booster, but also use an OM to EF adapter so I can use my manual OM lenses on my M43 cameras using this arrangement. In the past, certain Metabones Speedboosters, after a firmware update, would autofocus on Panasonic bodies only, not Olympus, nor Black Magic, but aperture control was available. Things may have moved on since then but I stopped looking as the price was too high for me to justify a Metabones.
 
Great thanks guys. I meant speed booster not speed ring hah

As soon as the black magic cinema 4k is released I'll grab one and a speed booster. Then I'll have a play.
 
A speed booster changes the maths a little on this. If you were using a standard adapter with no optics then the focal length of the lenses do any change. So a 50mm standard Canon EF lens would be a 50mm short telephoto on the m4/3 camera (effectively a 100mm equivalent lens due to the sensor being half the diagonal dimension of the 35mm full-frame). The Metabones speedbooster is a 0.64x converter so the same 50mm lens is converted to a 32mm focal length which is the equivalent of a 64mm lens on the m4/3 camera. Hope that’s clear :)
 
magicolor1 said:
A speed booster changes the maths a little on this. If you were using a standard adapter with no optics then the focal length of the lenses do any change. So a 50mm standard Canon EF lens would be a 50mm short telephoto on the m4/3 camera (effectively a 100mm equivalent lens due to the sensor being half the diagonal dimension of the 35mm full-frame). The Metabones speedbooster is a 0.64x converter so the same 50mm lens is converted to a 32mm focal length which is the equivalent of a 64mm lens on the m4/3 camera. Hope that’s clear :)
Click to expand...

Don't forget the boost in aperture too. The metabones are very expensive, there are third party options that work just as good as I posted above. Metabones have 2 variants, that 0.64x but also a 0.71x afaik. That's what the Viltrox is too.

http://www.viltrox.com/en/index.php?m=index&a=show&cid=145&id=181
 
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