Can somebody explain grey cards and SLRs?

Question

Can somebody explain grey cards and SLRs?

Answer 1

You use a grey card to get a get an accurate white balance reading of a scene. White balance refers to the light and affects the colors. Daylight and indoor lamp light have a different light color which affects how colors are seen. You want to adjust the camera light sensor so it reads the scene accurately.

Answer 2

A camera meters for 18% grey.  They print grey cards at 18% grey so you can meter off of it in whatever light you're using.  It's handy when you have tricky lighting, a high key shot, low key shot, etc.

It can be used for setting a white balance, but a white piece of paper would actually be better for that purpose.

Answer 3

Terisu's got the right answer.  I doubt I could say it better, but I'm foolhardy enough to try.

18% grey, refered to as middle grey, is Zone 5 in the Zone System - the middle between highlight and shadow.  Metering off of light reflected off of a 18% grey card means you're exposing for the midtones of the given light.  It's pretty accurate for metering unless there is some rather strange lighting situations going on.

Answer 4

They are right about the grey card helping with color and white balance and metering.  I use a McBeth color checker when I need accuracy for color and white balance

http://www.digital-photography.org/mcbet...

http://www.rawworkflow.com/products/gmb/...