Proper Exposure and How to use a Grey Card

[Rosy]

Hi Mike THANK YOU for this - Are Gray cards used for any type of setting? Indoor and Out? I read Bryan Peterson's Exposure and he meters off the sky in snowy situations - but i guess if it's on overcast day then the gray card is more reliable

 

[Josh66]

You can use a gray card any time - as long as it's in the same light that the subject is in.

On an overcast day, the sky is pretty much gray, so you can use that instead. On a sunny day, green grass will work instead of a gray card too.

In snowy situations you don't want to meter off of the snow, because if you did the photo would be underexposed.

 

[Rosy]

Thks Josh - i guess outdoor sunny days are quite challenging as well - you meter off the grass, then? If your subject is in a shady area then you can meter off the subject, correct?

 

[Big Mike]

You can meter off of grass, because (for the most part) grass is about the same reflectance as a grey card. It's certainly not fool proof, as grass can look many different ways.

If your subject is in a shady area then you can meter off the subject, correct?

That's not really the idea. That would only work if your subject (or the part that you meter off of) is the same reflectance as middle grey.

The point of a grey card, is that it works in all situations....sunny, shady, snowy, indoors etc. The key is that you have to read the grey card in the same light that your subject is in.
So if you subject is in shade, then you put your grey card in that shade and take your reading. If your subject is in the sun, then you put your grey card in the sun and take your reading.