how to calibrate exposure with a grey card?

dinneenp

Call me stupid but how does one calibrate exposure?

I know you use a grey card for it but are there steps to follow or is it just take photos at the different exposures and see which one matches best?

Cheers,
Pa.

magicbastarder

hold the grey card in such a way that the light falling on it is similar to the light falling on your subject. meter off the grey card - whatever exposure the camera thinks is correct for the grey card should be usable for any subject in similar light conditions; the benefit being that the shade of the subject will not fool the meter.

Paulw

A grey card is not for calibrating exposure, it's for calibrating white balance.

But, getting the exposure right when shooting the grey card will give you a good idea of the exposure setting for shooting under.

magicbastarder

Paulw wrote: »

A grey card is not for calibrating exposure, it's for calibrating white balance.

it was originally invented to calibrate exposure, as it was printed to the same shade that camera meters are (were?) calibrated to expect from an average scene. maybe people are using them differently these days, but dineenp seems to be using it for the exposure functionality.

Paulw

A useful link to reference - http://www.digitalartsphotography.com/instructions.htm

But, yeah, I guess you can use it for exposure estimates too.

stcstc

no it is for exposure too

18% grey is what you camera meter is trying to meter to, so a 18% grey card will give you a correct meter reading

magicbastarder

Paulw wrote: »

But, yeah, I guess you can use it for exposure estimates too.

they were invented long before digital photography took off. it was their primary purpose; otherwise it would not matter what shade they were, as long as it was neutral. as stc mentioned, the standard is 18%.