Expodisc or grey card?
- Thread starter EOS7Pete
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EOS7Pete said:
Expodisc is good for setting a custom white balance in camera which is really important to get right if you shoot jpg. You can set a custom WB with a grey card but some people just take an extra shot of the card and its a one click in post to set WB if you shoot raw. This makes it quick during shooting because you don't have to keep setting a custom WB on the job for different light.
If its important to get really accurate colour you can use something like the xrite colour passport. It has a colour swatch as well as grey patches, you use software in post which generates a custom camera calibration from the shot for use in apps like LR and photoshop, and you then click the great patch for white balance. It has warmer and cooler grey patches that you can click to give the look you want but be consistent between lighting situations.
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For white balance or exposure?
Put it this way, I have a Kodak grey card but no Expodisc (and no intention of getting one), though they both do both. I use the 90% white side for white balance as recommended, and the 18% grey side as an exposure reference (though it's not quite neutral grey).
Put it this way, I have a Kodak grey card but no Expodisc (and no intention of getting one), though they both do both. I use the 90% white side for white balance as recommended, and the 18% grey side as an exposure reference (though it's not quite neutral grey).
HoppyUK said:
I thought you can use the 18% grey for white balance too, or any neutral tone really? I usually click on a neutral tone in post and adjust to taste or use the xrite checker but I have no idea what % that is I just click the WB square. With people shots I don't usually like completely neutral white balance and I'm pretty sure expo make a warm disk for this purpose too.
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Sure, you can use any neutral tone (ie equal quantities of red, green and blue) for white balance, it's just that the Kodak card is not neutral grey - nor does it claim to be. It's guaranteed within 1% of 18% reflectance, but mine is fractionally greeny-yellow.
Kodak say use the white side for WB, which is 90% reflectance and guaranteed neutral. Camera manufacturers say use white, I think because it's less prone to under exposure and therefore chroma noise upsetting the reading. Neutral white is also quite an easy target to find in the field - paintwork, table cloth, cuffs and collars etc, whereas picking a neutral grey tone is pretty much impossible. The only danger with white is that it might be blown and therefore useless!
Edit: I agree that dead neutral white balance doesn't always look best. And neither is it necessarily 'correct' - the true colour of an object changes dramatically according to the light falling on it. We just take daylight to be the reference colour, but actually whatever looks best is 'optimum' in that sense. We are actually quite tolerant of colour shifts away from technically dead accurate, but very sensitive to changes shot to shot, ie if a subject is a bit warm or slightly cool, it will look fine either way, but when you put the warm one next to the cool one, that's really noticeable. Using AWB is a bu99er for that, better to use one of the pre-sets or a custom WB, and leave it there to keep it consistent.
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