light meter

[Jim Nelson]

Hi, can someone please help me out.

 

-When you shoot a scene and you use a digital light meter, do you have to select on the light meter which ISO you have? And do you have to select which frame rate you're using as well?

 

-Also on the regular light meter (the one that's not digital) the frame rate cannot be changed. What do you do if you are shooting at a frame rate that's different from the default one?

 

 

Thanks for your help.

[Michael Collier]

Iso and fps are selected on the digital ones, yes.

 

For older analog ones (having never used them) I would assume you would build the overcrank/undercrank into the rating. If you have 500t that you nominally rate at 320 for 24fps, then if you were to overcrank to 48fps, you would rate your film 160 (digital this is not necessary, it automatically calculates for the frame rate you have selected.

[Adrian Sierkowski]

Some analog ones have different FPS's on them as well. I am pretty sure the Sekonic Studio II is one such meter (sadly I have one of them as my backup meter but I'm so addicted to the L758 I hardly use it)

[Jim Nelson]

So what you mean is with digital light meters, you have to select the frame rate and the ISO?

 

On analogue light meters, there's different shutter speeds and frame rates written, but you can't select them. You can only have the default shutter speed and frame rate. I don't understand what you do if you want to shoot at a different frame rate or at a different shutter speed than the default one?

 

 

Thanks for your help.

[Adrian Sierkowski]

Yes, on a digital you set the frame rate and the ISO same as you do on an analog meter. On my studio II it works like an abacus almost. You twist the dials so that the number reading up top lines up with the number reading below, and then to look under the film speed or shutter speed you're shooting at and that's your F stop (if you've set the ISO properly).

[Jim Nelson]

Thanks for your help.

 

-When you shoot a movie, do you have to also select on the digital light meter which shutter speed you're using?

 

-Also on analogue light meters, the frame rate and shutter speed are already set for you, you can't turn the dial to change them. What do you do if you want to change them? Im sorry if I keep asking this analogue light meter thing, it still a bit confusing to me :(

 

-And my last question is: does the frame rate have an effect on the f-stop you get? What I mean is, if you shoot for example at IS0 500 and the foot candles are the same, shutter speed is the same. Just the frame rate is different. Will the light meter give me a different f-stop?

 

 

Thanks again for your help.

[Adrian Sierkowski]

I think your analog meter is broken.. it needs to be settable, depends what meter it is.

 

 

the FPS will do the math for shutter speed. It's 1/48th of a second for 24fps with a 180 degree shutter (standard for film).

 

frame rate also effects shutter speed. if you're shooting 24fps you'll have 1 exposure, if you shoot at 48 fps (double the frame speed) you need 2x as much light for the same exposure because the shutter speed is now 1/2 of what it was (1/96th of a second for 180 degree shutter).

 

the formula is as such:

 

Shutter Speed= (FPS*360 degrees)/Shutter Angle

 

or 1/48=(24*360)/180