Ramping Problem??!!! help please

[Keir Suggett]

gday i've just got a shutter compensation speed ramp problem with
the red camera. I am ramping from 25-100 frames and have the shutter set to relative, however it wont self compensate for exposure and gets darker
as the ramp increases frame rate. what box do i tick to make it compensate?????? please help

 

[Pietro Impagliazzo]

Isn't relative the mode where it gives you a shutter angle instead of a number?

So if it's 180 it will expose each frame rate with 2x the fps number.

So I guess things are normal there.

But can you compensate with shutter? I think that would become impractical after twice the fps or so.

 

[Alex Carr]

Be careful when shutter angles change on the camera, like when set in relative... Under some situations your entire image will flicker at different rates as the shutter changes.

Basically avoid magnetic ballast HMI's at all costs, NO MATTER WHAT. or you'll ruin your shot.

The only other way is an Iris Pull after the ramp has been triggered.

 

[T. Glen Phelps]

The Red does not "self compensate". With the shutter set to relative, the shutter angle remains at 180 degrees (i.e. 1/2 the frame interval). As the frame rate increases the shutter speed increases (180 degree shutter at 25fps = 1/50th sec, 180 degree at 100fps = 1/200th sec) and the exposure decreases. The only way to compensate would be to somehow ramp the iris open an equivalent number of stops as the shutter speed increased. The only other way would be to keep the shutter speed set at constant setting (maybe 1/200th sec) and live with the reduced motion blur that would cause.