1st time. shutter speed ? how do you use?

[johnney durdin]

sorry for asking such a lame qwestion. but i have allways shot on auto settings.

can some one explane and give an exsample of hoe to use dif shutter speeds
in lamons terms.

sorry again but want to learn.
thanks

 

[Nick Gardner]

To simulate normal 24fps film shutter angle of 180 degrees, shutter speed is 1/48 of a second.

Faster shutter speeds give less motion blur, more stacato look, like action scenes in saving private ryan, black hawk down, etc. Usually 45 degrees, which equals 1/196th of a second (check my math, but around 1/200th)

Slower shutter speeds give more motion blur.

Shutter speeds can also be adjusted to eliminate 50hz lighting flicker (1/50th)
And crt monitor roll bars.

Of course all shutter speed changes affect exposure accordingly.

Cheers,

Nick

 

[David Mullen ASC]

If you are trying to mimic the way film cameras replicate motion, most of them start out with a 180 degree shutter angle (a spinning half-circle disk) as a standard, which means that the shutter is closed for half the frame rate time, and exposing for the other half.

So at 24 frames per second / 24P, you'd use a shutter speed of around 1/48th of a second (half of 1/24th). It's not that critical, in the sense that depending on how much motion is in the frame or how fast the camera is panning, it's not always easy to tell a shutter speed adjustment in either direction, within reason (for example, 1/60th instead of 1/48th -- hard to tell a difference when things are moving slow in the frame.)

As you move farther from that principle of half the exposure time of the frame rate, you get certain motion artifacts. Too short of an exposure time, like 1/100th, 1/200th, etc. and the motion blur gets less and less and the motion looks crisper, more staccato, jumpier or jerkier (for example, some action scenes in "Saving Private Ryan" were shot at 24 fps at the equivalent of 1/192 of a second, i.e. a 45 degree shutter angle).

Also note that you lose more and more exposure the shorter and shorter you make the shutter times.

Whereas most film cameras are limited to 180 degrees, a few 200 degrees, a digital camera can have longer shutter times at 24 fps, like 1/32nd or even "no shutter" at 1/24th, the maximum time possible at 24 fps. You get more exposure (a full stop more exposure at 1/24th instead of 1/48th) but you also get a lot more motion blur, which can look rather smeary or ghosty with fast motion.

 

[johnney durdin]

thanks for the help do you know of another forum that i can ask qwestions like that . i know most of the cats on here are pros.


"Usually 45 degrees"" i do not understand that but the first part i understand
thanks again

 

[David Mullen ASC]

There is a good example here:
http://en.wikipedia.org/wiki/Rotary_disc_shutter

Think of the mechanical shutter in a film camera as a spinning circle with a pie slice cut out to allow light to come through and expose the film in regular intervals. A 180 degree shutter is a half-circle. A theoretically spinning solid shutter that is always closed would be 0 degrees. A shutter that is completely open (and thus missing) would be 360 degrees.

A film camera needs to have time when the shutter is closed so it can advance the film to the next frame in darkness before allowing light to expose it again.

So a 90 degree shutter is half closed down from a 180 degree shutter (1/4 open rather than 1/2 open) and thus loses a stop of exposure (every halving or doubling of exposure equals one stop) and half of 90 would be 45 degrees ( 1/8 opening in a circle) and losing another half would mean losing another stop of exposure, or two stops lost compared to 180 degrees.

Most digital cameras though have electronic shutters selected by speed (shutter time), not spinning mechnical shutters selected by angle of openness.

 

[johnney durdin]

that makes a lot of sence to me thank you.
any more you can throw at me i understood all about the pie. "i like food"
can you recomend any sites or books that i can further my know how?

 

[johnney durdin]

just saw the wik ref thanks