Grey card

[Nogbad]

Hi I saw a a "Grey card" advertised today.

What's it for, how do you use one?

I understand you use it to get an exposure reading, but how do you do that?

Do you carry it with you all the time?

How often do you need to use it?

Is it for awkard exposures?

Do I need to buy one?


Nogbad

[Canis Vulpes]

Firstly, I dont think you need to buy a grey card. A grey card can help manual exposure as 18% grey lies in the middle of histogram on DSLR. A grey card is more useful nowadays setting manual white balance. Most DSLR's have a custom mode for white balance requiring a test shot. This test shot is taken of the grey card in light of any real photos. White balance should be spot on.

[robski]

If your looking for colour accuracy it is a useful tool. Having part of the grey card on the edge of the frame helps serve as a colour reference. You have a know neutral reference for checking and correcting the colour balance in post editing.

For example the Auto white balance may add too much blue to a shot of grass and yellow flowers.