There are times when you need to capture an event, but you can’t
spare the time to be there every day. If you can place your camera in a secure
location, you can use GBTimelapse to capture the images automatically. It can
start and stop at set times each day and automatically adjust the exposure for
flicker-free capture.
I placed a camera in an upstairs window with a view of the turkey’s daily route. I used a Bower 24mm manual lens with the aperture constant at f/5.6 to prevent any aperture flicker and I draped the back of the camera with a black cloth to block any window reflections.
I needed a wide angle lens to cover the unpredictable turkey wandering, but the full wide angle image included a bright sky and foreground.
To get the correct exposure in the middle ground, I used
GBTimelapse’ new luminance region option. Instead of calculating the histogram
over the full frame, you can specify an arbitrary sub-rectangle for the
histogram. Here you can see the region I set to eliminate the sky and
foreground. This guaranteed a proper exposure of the middle ground regardless
of how bright the sky was.
Because I was capturing large/fine jpegs with at 5760x3840,
I was able to crop down to 1280x720 in After Effects and pan as the turkeys
wandered across the full frame.
The turkeys start their parade just before dawn, but the
sunrise time changes rapidly in the fall at this latitude. So, I set the
GBTimelapse program to start every day at 25 minutes before dawn and to run for
30 minutes.
My initial exposure at that time before sunrise was about 2
seconds, f/5.6 and ISO 100. Each day was different because of the different
cloud cover and lighting, but GBTimelapse AutoRamp would settle on a good exposure
in just a few frames.
By using bulb mode, I was guaranteed to get smooth exposure
changes with no Tv stepping as the scene brightened by more than 4 f-stops over
the 30-minute period.
A 4 second interval with a 2 second exposure gave a nice “180
degree shutter” look to the video instead of the choppy look from a shorter
exposure.
For our professional clients...the ability to run automatically can greatly increase your productivity. You should consider it the next time you can place a camera in a secure location.