Using vintage 16mm lens with Original Blackmagic Pocket Cinema Camera

iKokomo · Dec 2, 2019

I found a Rainbow TV Zoom Lens H6X8 8-48mm 1:1.0 1/2” C Mount Lens at a thrift-store that I would like to use with my 1st generation, 1080p Blackmagic Pocket Cinema Camera with a Super 16 sensor.

Whenever I use it there is a massive vignette and it is impossible to focus without closing the aperture all the way down.

I know I need some sort of adapter, but I was wondering which adapter I needed?

Derrel · Dec 2, 2019

Not sure an adapter will solve the underlying issue.

VidThreeNorth · Dec 2, 2019

I don't have that camera and I don't have that lens, so I can only give you theories:

- Nope, skip it. What I thought might work is almost guaranteed to fail. I have no workable suggestion.

[2019-12-03]

Ok, after re-thinking my idea, this is might be possible:

1. If you can get a "tele-converter", for the camera mount -- probably a 2X.

2. Then add the C-mount adapter to the tele-converter.

The PROBLEMS:

1. You will need enough clearance to focus to infinity. The tele-converter's lenses might not allow this.

2. Your aperture will be "darker" with the tele-converter on. F4.0 becomes F8.0

3. Sharpness will be terrible. If you had 50 lines per inch resolution from the main lens it will drop to below 25 lines.

So even if it "works", the results are not worth the effort.

VidThreeNorth · Dec 3, 2019

If you really feel like using that lens, then you might get a Go-Pro and a C-Mount adapter. There are videos on YouTube showing how to do the modification. It is a bit dangerous, and you might end up wasting the cost of the Go-Pro, but that is realistically the best you can do.

Remember that a "TV lens" was only meant to give about 522 scan lines of resolution, and even weaker resolution horizontally. They did not have to be very good, so they generally were not.

VidThreeNorth · Dec 4, 2019

One last issue: If focus is really "off" or "impossible as-is" you might have a CS-mount lens instead of a "C-mount" lens. The CS (C short) mount needs an extra spacer. B&H has the spacer. Most TV equipment should be C-mount. CS-mount was usually used for bellows style equipment like "technical cameras" and enlargers. I had a CS-mount lens for my enlarger. But there have been cameras like closed-circuit and industrial cameras that took CS-mount.