View Full Version : Shutter angle exposure pull
Sergei Franklin
02-08-2010, 09:42 PM
I would like to do a exposure adjustment during a shot by changing the shutter angle as can be done on Arri 435.
I image it like the ramp function with an on event trigger, except it would not be tied to varispeed. There would be settings for beginning angle, time and end shutter angle.
Sergei Franklin
www.sergeifranklin.com
Tom Mitchell
02-09-2010, 08:08 AM
I'm not sure how the 435 handles this but if you where changing from 180 to 45 degrees you will be losing two stops? the point being how to you ensure you have a constant exposure?
as far as the red in concerned it only changes its angle in varispeed whilst doing speed ramps.
Though i think it is a useful option to have the camera control the iris perhaps using one of it aux outputs to adjust according to angle.
I can see the scarlet having this as i think there trying to make a point and shoot fully auto mode.
Jeff Kilgroe
02-09-2010, 08:22 AM
The reason for ramping the shutter is typically not for an exposure pull. It's for the effect of the changing shutter speed.
As of right now, the RED One can not do this. Perhaps with Epic or future RED One firmware builds.
Sergei Franklin
02-09-2010, 02:51 PM
It's about changing exposure like in a shot walking from outside to inside.
With an iris pull the depth of field will change so sometimes it is desirable to adjust via shutter angle instead.
This should be easy to implement in a future firmware version.
Sergei Franklin
Jeff Kilgroe
02-09-2010, 03:37 PM
Sergei, you would want to do this with filtration, not with a change of shutter speed. Changing shutter speed will effect the amount of motion blur as it's a change in exposure time.
Use a variable ND filter. Or stack two polarizers if that makes it easier to get your hands on equipment.
Either way, it should be easy to implement in a future upgrade. The camera already ramps shutter along with frame rate when its in relative mode. Which also has me second guessing myself. I don't have my RED handy at the moment, but will check later tonight. Perhaps it is possible to trigger a shutter event using the GPIO functions.