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Blackmagic Ultra 4k Studio Cam Low light performance issue!!!

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Steve Martin
Blackmagic Ultra 4k Studio Cam Low light performance issue!!!
on Apr 23, 2015 at 3:36:10 pm

Hi All,

We're having an issue with getting our BMD Studio Camera to give us adequate exposure in what I would consider good lighting in a controlled studio setting. Here's what we've got:

2 BMD Studio Camera Ultra HD
1 BMD Studio Camera HD
ATEM 1M/E switcher

Here's the test;

We've set up the BMD cameras in our studio shooting an evenly lit green screen wall. In the past we've shot in this environment using ENG style cameras (Panasonic HPX300) and Digital Cinema cameras (Panasonic AF-100). As an FYI, we wouldn't normally light a green screen this bright, we're using a target of 70 IRE to simulate sensitivity for skin tone.

In comparing the performance of the BMD cameras to both the AF100 and HPX300, we're seeing that the levels coming out of the BMD is significantly lower.

More details:
Comparing against the AF-100 we're using the exact same lens (Olympus MFT Zoom 2.8). Setting all cameras to 0db gain and making sure that they're all in the same frame size & rate (1080i 60fps) here are the scope luminance readings:

AF-100: 70 IRE
BMD Studio HD: 30 IRE
BMD Studio Ultra HD: 20 IRE
HPX300: 65 IRE (standard Fujinon that came with camera set to f2.8)

In order to get the BMD Studio Cams to reach 70 IRE on the green screen, we need to gain up to 12db which seems (to me at least) unacceptable, which adds in a level of grain we do not want to see. Also there are slight differences in IRE levels when we switch frame rates but not a significant difference.

Am I missing something? Is there a setting in camera or switcher that would help increase the light sensitivity without adding db/gain? Or are just stuck with how it processes light?

Production is fun - but lets not forget: Nobody ever died on the video table!

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