Metabones BMPCC Speedbooster for Nikon Lenses.

[Robert Hart]

This last few days I have been making an IMS-Mount for a Speedbooster purposed for the Blackmagic Pocket camera. It is possible "just" due to the IMS-Mount flange to focal plane distance being 19mm and the MFT-Mount used by the Blackmagic cam being 19.25mm. I had a notion that it would be handy for use on the SI2K which uses a sensor slightly smaller than the Blackmagic camera but is still regarded as being in the Digital Cinema Super16mm class.

Initial tests have been encouraging that the device does as the manufacturer claims. More light is introduced to the camera sensor. Whilst there remains some cropping of the image to the smaller sensor, the apparent sharpness of 35mm stills lenses is significantly improved over using them direct to the small sensor.

Using the speedbooster on the Epic/Scarlet/Dragon camera family may be unlikely due to the deep setback of the camera sensors within the case when compared to the original Red One. The original Red One has a mount adaptor system and the sensor is closer to the front of the body. As P+S Technik released an IMS-Mount for the Red One, this suggests that the Speedbooster could be made to work via a custom adaptor mount.

Why bother?? The use of the Red sensor cropped to 2K is a trade-off for higher frame rates. 35mm lenses tend not to perform so well at the smaller 2K image size. The speedbooster seems to restore the sharpness of the 35mm format lenses to become very favourably comparable to Super16mm lenses and most of the field-of-view/perspective of the 35mm lenses. Because a faster shutter speed/frame rate requires more light, the Speedbooster would help there too. The difference in perspective should be less pronounced.

 

[Robert Hart]

A quick happy snap, no post-sharpening or colour-grade applied, just a frame with low contrast look applied, exported direct by the camera. Lens - 50mm f1.4 Nikon AIS, IRND1.8 filter, 1/50th shutter, conditions - 8/8ths overcast, approx 2pm, late winter, sun behind camera. The flowering bush is locally known as the "bacon and egg plant".

Furthur to above, whilst the Speedbooster in its entire state might not be workable with the Red Epic/Scarlet/Dragon family, the optical group in a custom fitting might.

For curiosity sake the following measurements apply to my arrangement for the SI2K but should be close for the Red family.

The rear element of the optical group is 8mm from the sensor. This likely rules out using the motion mount. The widest outer diameter of several steps along the optical group is at the front - 32mm. The normal Nikon flange to focal plane distance is 46.5mm. With the BMPCC model speedbooster optics in the path, the Nikon flange moves rearward to become 38.5mm. This may be too far rearward within the camera casework for the Nikon mount diameter to fit within.

However, a custom version for PL-Mount lenses may be feasable with a flange to focal plane distance shortened from 52mm to 44mm.

The 54mm diameter of the PL-Mount shoulder and rearward depth of the shoulder running foul of the camera casework may be the dealkiller.

There you go. Some useless info for you. For practical versatility it seems again that the original Red One still rules.