September 26, 2016 at 11:35AM, Edited September 26, 11:38AM


Blackmagic cinema camera 2.5k MFT crop with MFT lenses?

Thinking about buying the BMCC 2.5K MFT and some Samyang lenses. In particular:

-Samyang 50mm f1.2 AS UMC CS Lens - MTF
-Samyang 21mm f1.4 ED AS UMC CS Lens - MFT
-Samyang 85mm T1.5 AS IF UMC II Video Lens - MFT

Will these lenses crop on this camera? If they do, why? Surly if they're the correct lens for the mount and the sensor they shouldn't crop. Right? Appreciate the help.



Yes. The BMCC sensor is smaller than a standard m43 sensor, so a proper m43 lens will be slightly cropped by the smaller BMCC sensor. You may be too young to remember when Canon launched their first "pro" digital camera, the EOS 1D. Its sensor was larger than APS-C, but smaller than FF35. It had a standard Canon EF mount, just like its FF35 film camera cousins, but because that sensor was 30% smaller, it had a 30% crop factor. That's just the way it is.

The BMCC camera works well with m43 lenses, as long as they don't have any electronic focus or aperture systems.

September 26, 2016 at 12:33PM


So each of these lenses will have a 1.3x Crop on the BMCC 2.5K MFT? 21mm = 27.3mm?

Joseph Nowell

September 26, 2016 at 12:49PM

No. The 1.3x crop factor was related to the Canon EF sensor back in the day, illustrating the point that a lens mount does not guarantee any properties about a sensor size.

That said, you can use the Abel Cine FOV tool to really compare true m43 fields of view with the BMCC:

The AF100 was a true m43 sensor size, which has an image diagonal of 20.1mm. The BMCC has an image diagonal of 18.14mm. That's a crop factor of 1.108. So a 50mm lens on a BMCC behaves like a 55mm lens on a m43 camera.

September 26, 2016 at 1:24PM


Ok great. thank you so much.

Joseph Nowell

September 27, 2016 at 5:16AM

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