Friday, November 14, 2014

Wild Turkey Parade - BTS with GBTimelapse Automatic Unattended Operation

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.

Here’s a behind the scenes look at how I used GBTimelapse to capture the daily “Wild Turkey Parade“ across our property.

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.

I set the GBTimelapse AutoRamp parameters to keep the bulb time between 1 and 2 seconds. Each time GBTimelapse adjusted the bulb time down to 1 second, it would halve the ISO and double the bulb time back to 2 seconds.

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.

This may not be the most interesting video, but the techniques I used are very powerful!

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.

Wednesday, November 12, 2014

GBTimelapse 3.10 - Now with 3-axis eMotimo TB3 Control

Looking to achieve the time-lapse "holy grail" with your motion control gear?  You are in luck!  GBTimelapse 3.10 has added several features focused on achieving the elusive sunset, sunrise and overnight "holy grail."  Read on!

New Master/Slave Modes

GBT version 3.10 adds several new Master/Slave modes. These new modes enable you to get GBT’s Holy Grail AutoRamp power with virtually any motion control device!

As an added bonus, GBT 3.10 also...
  • Adds even greater compatibility with the eMotimo TB3 Black.
  • Adds the ability to synchronize multiple cameras connected on multiple computers (more about this in future posts).

New eMotimo Slave/TB3 mode features

  • Uses third axis for slider control (Rhino, Dynamic Perception or any other stepper).
  • Uses TB3 joystick setup parameters for 2 and 3-point moves,
  • or optionally use GBTimelapse control panel to setup all parameters for 2 and 3-point moves.
  • Enter TB3 mid and end-point Pan/Tilt positions precise degrees and slider position in inches or metric units.
  • No need to move the slider to the end-point, just type in its end value.
  • Save and Load all TB3 parameters from the computer for repeatability later.
  • Use GBTimelapse to schedule time-lapse start at a later time for unattended operation.
  • Uses GBTimelapse Holy Grail AutoRamp for bulb ramping and ISO control in changing light or day/night transitions.
  • Use GBTimelapse live-view screen for precise alignment of start and end points.
  • Use GBTimelapse history screen to see progress during a time-lapse session.
A three-axis demo...

A setup tutorial...

And TB3 driver/firmware installation...