Shutter Speed

[andythefilmer]

Hi guys, so I have been wondering this for quite some time. Everyone is saying that you should always have your shutter to be twice your frame rate. But, I really don't notice a difference in motion at all, except light loss at a faster speed, or blur at slow shutter mode. I just want to know why exactly it should be twice the frame rate, and how it really affects your image. Thanks.

 

[groveChuck]

It's to most closely replicate the "film look." In film, it's called "the 180 degree shutter."
Film shutters are a semi-circle that spins around exposing each frame of film as it advances.

In video, if you have a slow shutter, it will smear some, and a fast shutter will look stroby.
So if you want the most filmic look, your shutter speed shoud be double your frame rate.

This probably explains it better than I do:
http://blog.planet5d.com/anh

 

[Dvx Kid]

but if your shooting (24p with 1/48) in dim or low light it makes the image appear darker than it would with 24p with 1/24
? so basically you have to take a risk of a low lit shot or possibly a blurry image (if you do any decent quick movement?)

 

[blondie.]

I've never been preoccupied with this - I shoot skiing/action sports, so I like to have that faster shutter (I try to be around 1/120) but I've heard about this before...it makes sense, I guess, although I've never noticed any difference besides the blur.

 

[Dvx Kid]

so higher shutter gives you more blur or less?
im thinking less?

 

[Barry_Green]

but if your shooting (24p with 1/48) in dim or low light it makes the image appear darker than it would with 24p with 1/24
? so basically you have to take a risk of a low lit shot or possibly a blurry image (if you do any decent quick movement?)

Exactly. The choice is brighter images vs. blurrier movement.

 

[andythefilmer]

Thank you guys. So on the DVX, what is the shutter? I know it isn't a rolling shutter, but is there a physical shutter in front of the sensor?

so higher shutter gives you more blur or less?
im thinking less?

The slower the speed, the more motion blur.

 

[Dvx Kid]

thanks for answering my q's

 

[renegadewill]

Don't be afraid of shooting high shutter speeds. Think about all of the insane 90 degree shutter work in saving private ryan.

 

[Barry_Green]

Thank you guys. So on the DVX, what is the shutter? I know it isn't a rolling shutter, but is there a physical shutter in front of the sensor?

No, it uses a process that's referred to as a "global" shutter. It just electronically decides to stop receiving any more light, simultaneously, so the entire frame "shuts off". A rolling shutter progressively scans and exposes each line, a global sensor like a CCD simultaneously exposes the entire chip.

 

[groveChuck]

A rolling shutter progressively scans and exposes each line, a global sensor like a CCD simultaneously exposes the entire chip.

That's why CCD cameras don't have the dreaded skew you hear about in some CMOS cameras, where, in a fast pan, the bottom half of the frame lags behind the top half.

And Will is right- obviously there's no problem with faster shutter speeds, if that's the (highly stylized) look you want. Will has mastered that look in his music vids.

But of course it's something you can't undo in post if you decide you want a smoother look...