Using White/Grey/Black calibration target

kat.hayes

EOS T7i
Nov 25, 2014
76
0
I understand how to use a white balance card to calibrate the WB of a camera, though how do you use a calibration target that also includes black and middle grey?

Is this intended to be used mainly to edit your photos in Photoshop or Lightroom to set the black, middle grey, and white point OR do you adjust exposure in camera based on the target? If so, how?

Thanks.
 

privatebydesign

Would you take advice from a cartoons stuffed toy?
Jan 29, 2011
7,967
1,178
119
You can use them for all kinds of things.

In Photoshop you can actually do three white balances for all three tones, this gives you a sudo camera profile and can be very useful when you have complicated WB issues or bad camera profiles.

You can use them to set black and white points too, but bear in mind if your white wasn't white this can lead to strange tonal imbalances, same with the black point though that isn't as common an issue.
 

kat.hayes

EOS T7i
Nov 25, 2014
76
0
Do you use one of these black/grey/white targets to calibrate exposure in camera? OR is it just for using in PS and LR?
 

privatebydesign

Would you take advice from a cartoons stuffed toy?
Jan 29, 2011
7,967
1,178
119
Depends on the situation, in the studio for portraits or product work I'll take one with colorchecker to dial in exposure, but mainly it is for post processing purposes especially in tricky lighting etc.
 

SecureGSM

2 x 5D IV
Feb 26, 2017
1,346
325
yes, you do. this is one of the designations of the 18% grey (50% reflectance level) card.
you spot meter the grey card in order to place your mid greys right in the middle of histogram.

As to white balance adjustment, I really prefer to use grey card rather than black or white as the white card can skew the tonal range in a really awkward way.

kat.hayes said:
Do you use one of these black/grey/white targets to calibrate exposure in camera?
 

CanonFanBoy

EOS 5D SR
Jan 28, 2015
4,166
1,739
Irving, Texas
applecider said:
Sort of related, do the canon lens leather grey covers have the 18% grey like a grey card? Can they be used for WB in another way?
Not sure about that, but I think some of the folds and wrinkles cause the shading to vary on the leather. That wouldn't be good for calibrating. I would think one wants a solid flat card for a more consistent shade of grey.