Three Tools for White Balance Correction
- By: Luis Argerich
In this article I will quickly review how to use three popular tools for White Balance correction: The WB gray card Whibal, the Expodisc and the SpyderCube.
The Whibal Card
The Whibal is one of the most used products for WB correction using a gray card. The idea is very simple: The card is painted in a neutral color so it can be used for WB as a neutral spot. To use the card you just place it at the scene or hold it in front of your lens to take a shot. It doesn’t need to be focused and it doesn’t need to cover all the frame. You can use the same settings you use for the normal photo.
You can use the card shot to set a custom WB temperature in your camera or you can just save it and later use it for WB correction of the RAW files. You click with the WB drop tool in the car and apply that WB setting to the rest of the photos.
WB tools are easy to carry, easy to use and relatively cheap. The disadvantages of using a gray card are:
– You need to avoid reflections when you shoot the card.
– It can be difficult to capture different light sources -if used- in just the small card
– The light at the place you shoot the card must be the same light at the scene
The Whibal and other WB cards usually include a complete black and complete black surfaces that can be used to set the white and black points when processing the photos. Find it on Amazon.com.
The Expodisc is a translucent lens cap designed to be neutral in color. While the gray cards use reflected light the expodisc uses incident light. To use the expodisc you hold it as a lens cap and point the camera towards the light source. That usually means turning the camera around facing the opposite side of the scene. Then you take a shot using Aperture priority mode letting the camera choose the exposure. That shot can be used to set the custom WB or to correct WB when processing the RAW files.
The expodisc can capture many different light sources at once,including light from difficult directions, reflections are not a problem its disadvantages are:
– If the light at the camera position is not the same as the light at the scene it won’t work.
– It’s expensive.
– Can’t be used to set white and black points
The expodisc can also be used to measure the amount of vignetting of a particular lens and then using that information to correct the vignetting in software. In astrophotography it’s useful to take flat-fields used to correct uneven illumination in the sky and vignetting. Find it on Amazon.com.
The Spydercube is a new and interesting tool for WB correction. As its name indicates it’s a cube that can be held from a string, placed on it’s little stand foot or attached to a tripod socket. To use it you just shoot the cube or the scene with the cube in it. The gray surface in the cube works in the same way as a gray card. The metallic sphere on top can be used to check specular highlights and there is a light trap at the bottom that works perfectly to set the black point.
The cube is an enhanced version of the gray card so it has the same disadvantages. Find it on Amazon.com.