The Online Resource for Sports Photography

A special gallery created by member
Guy Rhodes
"Discharge Light White Balance Tests"     [index] <<- Previous Next ->>
Mercury Cycle Color Shift A second whip-pan bulb exposure of a mercury vapor lamp (as commonly used in gyms and outdoor sports venues) reveals that it too pulses. As mercury sources offer a broader (yet still gross) spectrum of color, you can see that the peaks of the pulsing are green/blue, whereas the ends fall off into a reddish cast. The only way for photos taken under this light source to not vary in color would be for the exposure to capture at least one full cycle (or 1/60th of a second, from red to blue/green). Shooting faster than the cycle will result in color casts and exposure differences (a photo shot at point A in the cycle will have a different color cast as point B ***no matter what custom or preset white balance you've set***.