Monday, January 29, 2007
No more starry eyes, almost. . .
Have you ever noticed that most night pictures taken with camera traps look flat and the animals’ eyes glow like their brains are on fire? These are two bothersome biproducts of current camera trap technology (among others). They are caused by the camera’s flash, which illuminates the subject head-on. Starry or glowing eyes are caused by a structure associated with the retina. It's called the tapetum lucidum. In dim illumination, when the pupils are dilated, the light from the camera’s flash bounces back from the tapetum. But when artificial light enters the eye at an angle, the reflection is diverted. No starry eyes.
As for flash pictures with the "flat 2-dimensional look", it is simply caused by the lack of shadows when the flash is positioned near the shutter.
A few weeks ago, my friend Ed Gould shared the "fat cat" blog with a professional photographer, who suggested that positioning 2 flash units with slaves to the left and above would give the photos a great deal more depth and improved background lighting.
I dug up an old electronic flash and a slave, and neighbor Richard kindly made me a waterproof mount. A few field trials taught me that the AA cells lasted only a couple of days when the flash was left "on standby". So I wired the flash to an external holder for D cells, which have a much higher mAh rating—and longer battery life.
What I didn’t know was whether the camera flash could be tuned down enough to trigger the slave but not cause eye shine.
I found out last week. Both Zorrilo and Stinkarella visited the "set". For some mysterious reason, Stinkarella's eyes always seem to "burn bright". The creature must be stoked. I think the camera flash would have to be deactivated to circumvent those burning eyes. But I was pleased to find that a few pictures of Zorillo showed off a pair of lovely twinkling skunk-peepers. The problem of starry eyes isn't completely solved, but I'm getting closer. . .
(As for flat pictures, I'll have more to say on that topic when I work out the optimal angle of the external flashes).