Varicam ASA

[Leo Ticheli]

Hi Kevin,
ASA does not change as the frame rate changes, of course you must adjust your iris when you change frame rates just as you would with a film camera.

I should point out that the VariCam has a special feature that allows you to change frame rates without adjusting the iris! This is primarily for ramping the frame rate in shot; you set the shutter to either 1/60 or 1/100 and then you can ramp with constant exposure.

The VariCam, and any video camera for that matter, does not have an “ASA.” The sensitivity of the camera varies over a wide range depending on your individual settings. I’ve set my VariCam up to have a sensitivity roughly equivalent to 1000 ASA, but hate the look at that setting; I most often have the camera setup somewhere around 200 ASA using Film Rec and a Dynamic Level of 500.

Professor John Sharaf recommends a lower Dynamic Level, by the way, and that gives you a higher “ASA” and more contrast with the highlights clipping more.

I am aware of the sensitivity of the camera in ASA terms only for planing the lighting. I must emphasize that you are treading on shaky ground if you try to set exposure with the VariCam using a light meter; it’s much better to use a good HD monitor and waveform monitor to view area of clipping.

To further complicate things, it’s reported that the sensitivity of the camera may change with the light levels; it’s not linear. At low light levels you may find the “ASA” different from high light levels.

I hope this helps.

Good shooting!

Leo