April 21, 2018, 02:27:34 AM

Author Topic: What is the actual time between the pre-flash and the exposure flash?  (Read 2823 times)


  • EOS 6D Mark II
  • *****
  • Posts: 332
  • 5D4, 1DX
    • Forest Metrix
Odd question...

I found an insect. I believe it's a soldier bug. Whenever I attempted to take a picture of it, it would anticipate the flash and jump up before the exposure would happen. I'd have a picture of an empty leaf. It happened a couple dozen times.

Thinking the E-TTL pre-flash might be tipping him off, I moved the flash to manual and was able to photograph him. Put it back on E-TTL, and he'd hop up, just over where I'd framed him, and land right back down on the leaf. I photographed a couple dozen other species that day as well, and a few more dozen in days past, and none of them exhibited this behavior.

I'm curious where I might find what the time in picoseconds/milliseconds/etc. is between the little pre-flashes used for calculating exposure versus the actual exposure flash. A pretty extensive Google search turned up nothing. I'd like to be able to calculate what this bug's reaction time would be.

Thanks for any help. -tig

canon rumors FORUM