18% of the gray board is a professional photographer in filming, in order to more accurately metering, and choose a metering tool on the CANON PowerShot SD950 IS Charger market at present is most seen kodak company produces 18% of gray board, the gray board of grey stain is a more precise tone, it can reflect the light of 18%, so the color is called "18%" gray.
All the metering table are 18% of the gray to set the exposure standard, it is because the gray board to to measure the light and actual photography to be taken when the light on the body is completely the same.
Ordinary photography lovers in filming,canon powershot sd980 is charger if no gray board to also can in metering (normal yellow color of skin glance rate of close to 18%), but need to increase a block or so exposure compensation, can obtain the exposure is the correct image.
With grey CARDS based on the exposure metering value portrait,canon powershot sd990 is charger the exposure is accurate.
