The leopards roaming the jungles of Malaysia are mostly jet black, and researchers for a long time did not know that they actually had spots. And, without a clear view of these complex whirls of spots that are unique for each leopard, scientists studying them could not easily tell the black leopards apart.
Apparently, it was by accident that, by reviewing infrared images taken during the night, researchers discovered that black leopards indeed had spots. The near infrared flash that was activated in the night revealed a hidden spotting pattern underlying their coat.
The infrared flash on the camera is automatically activated at night, but the team got the camera to fire the infrared flash during the day. They did that by blocking the camera’s light metering sensor, tricking the camera into thinking it was night and therefore triggering the infrared flash. In this way, they were able to clearly photograph the spots.
Now, I wonder if they could maybe have the same results by using an infrared filter on their cameras — or, simply force firing the infrared flash during the day as fill-in flash?