Correct shutter settings for progressive?

[Don Greening]

[Tony Robinson] ” I’m not quite sure what the most accepted standard for shutter speed setting is in progressive mode.”

Well there’s shutter angle and then there’s shutter speed settings. The generally accepted shutter angle for everyday video will be 180 degrees, which is the default setting on the EX. The shutter speed will be determined by the frame rate, so a speed of 60 if you’re shooting 30 FPS or 48 if you’re going with 24 FPS. To get a more stroby, “Private Ryan” look you start increasing the shutter speed. If it was me I’d start by increasing it by two fold and check the result. The shutter speed rule also applies to interlaced as well as progressive.

[Tony Robinson] ” Is it acceptable to just turn the shutter off when shooting progressive or am I mistaking smoother looking video for smear?”

It’s my understanding that by turning the shutter off the EX will automatically double the shutter speed with regard to frame rate. Not too sure about that though. My shutter button is always off and I’m always shooting 1080p 30.

[Tony Robinson] “Also, is it true the camera is more sensitive to light while on the interlaced setting?”

I can’t speak to that because I actually haven’t shot anything using interlaced since I bought the camera. I do know that it loses a stop or two of sensitivity when shooting 720p 30 and it’s also set to 60 FPS overcrank for the slow-mo effect.

– Don

[Craig Seeman]

Turning shutter off matches the frame rate. In other words 30p is 1/30, 24p is 1/24, etc.

So if you’re shooting 180° it’s actually halfing the shutter speed since 180° would be 1/60 at 30p, 1/48 at 24p, etc.

[Don Greening] “It’s my understanding that by turning the shutter off the EX will automatically double the shutter speed with regard to frame rate. Not too sure about that though. My shutter button is always off and I’m always shooting 1080p 30. “

[Bill Ravens]

Shooting progressive is the same as shooting interlaced, as shutter speed is regarded. When the shutter is turned off, the effective shutter speed is the same as the frame rate, ie, 24 fps is 1/24, 30 fps is 1/30, etc.

When the shutter is turned on, the slowest you can go in 24 fps is 1/32 sec.

As for exposure with interlaced vs progressive, interlaced appears to be more light sensitive because your essentially exposing two fields per frame ( 180 deg shutter) for twice the exposure. In progressive mode, you expose one full field per frame, so for the same exposure you need to reduce the shutter speed by 1/2.

[Terry Lecroix]

The whole shutter angle thing goes back to film shooting. At 24 fps the exposure for one frame is 1/48th of a second with a 180 degree shutter.* The frame is exposed for 1/48th of a second and then the shutter blocks the light for another 1/48th of a second while the next frame of film is brought to the gate for the next exposure. If your intention is to emulate film motion artifacts then turn on the 180 degree shutter. Obviously the shorter exposure time with cut into your low light sensitivity a bit.

Terry LeCroix
TerryLeCroix.com