Question abt electronic shutter

Parthiva Nag · February 21, 2012

Hey all, I had a question about electronic shutters on new age digital cameras like the arri alexa, phantom flex, red epic etc..

When one reduces the shutter angle to 45 degrees or lesser does it make the image sharper or the electronic shutter has another mechanism it works on? If someone would clear this doubt it would really help me out. Thanks

Brian Drysdale · February 21, 2012

The electronic shutter reduces the exposure time, so has more or less the same effect as reducing the shutter angle on a film camera. This will reduce the motion blur on the movement in the shot.

Parthiva Nag · February 24, 2012

Thank u Brian

Gregory Wilson · February 25, 2012

Parthiva,

An electronic shutter, in principal, achieves the same as a mechanical shutter. Narrowing the shutter shortens the amount of time the sensor is on, creating sharper images because of the reduced exposure time. Widening the shutter is the opposite, giving more exposure time and increasing the amount of blur. There are two kinds of electronic sensors though, there are Rolling Shutters; RED, Alexa, F65, Phantom HD and there are Global Shutters; VRI's Phantom Flex, all their V series cameras and some others, mostly hi-speed cameras.

Rolling Shutters turn on one horizontal line of pixels at a time, usually from top to bottom. They have there advantages and disadvantages. Some disadvantages are sheer, a "jello" like effect noticeable with fast pans, and another is if a strobe is used in a shot the illumination can unevenly cover two separate frames, like the bottom half of one frame and the top half of the next.

Global Shutters turn on all the pixels at the exact same time. Its debatable but, higher-end rolling shutters are said to have a more "filmic" look because the sensor's method of turning on re-creates the path of a mechanical shutter. The new Sony F65 there will have a real mechanical shutter moving in conjunction with the electronic shutter, which will help eliminate sheer during pans or objects moving quickly across the frame.

Hope this help.

greg