Mid% - Mid% Filter is similar to the Bright% Filter, except affects only the mid tones within the selected part of the image. Use in conjunction with Bright% for a good overall lighting effect. The Mid% range center sliders and range gradient bar, immediately to the left, allows you to visually control the Mid tone tonal range.
Gamma - Gamma allows control of the range between the darkest and lightest areas of your image.
Lum% - Lum% adds overall brightness or darkness to the frame. Shadows, mid tones and hilights will all be affected.
Bright% - Bright% multiplies the amount of light within the selected part of the image. Mid tones and highlights are affected, while dark shadows are not affected. Use Bright% to adjust the lighting within your image without resetting the scene’s lights or raising the ambient light level.