Spot Meter For Sunset

[4knewave]

Will a spot meter reading of the sky yield a correct exposure for a sunset? (reading either the orange or blue part of the sky) Or will I end up with a image that looks under exposed and middle gray?

 

[Guest]

Spot meter sun

Spot meter sun

You can spot meter either the sun or the sky, but don't forget the reading it gives you will make it your 18% gray value. You have to interpret the reading and know that you will have to open up the iris more to give the bright sun or sky its true value. If you spot the sun open up more than you would if you spotted the sky.

 

[4knewave]

Thanks, thats what I expected. About how much should I open for the sky (read for sun ball about 2 stops). Would 1/2 a stop open be suffice?

Cheers

 

[David Mullen ASC]

Depends on the dynamic range of the format you are shooting in terms of holding highlight detail. For film, you either find a spot in the sky that you imagine is close to 18% grey in value, or you find a lighter area and guess how many stops over 18% grey it is. You figure that to hold color, it probably can't be exposed more than 2-stops overexposed before it washes out, but that five stops over 18% grey is essentially white. However, for sunballs, it depends on how large in the frame they are -- in a wide-angle shot of a sunset, you'd expose for the color in the sky, but in a 1000mm shot of the sunball, you'd expose more for the sunball.