Saturday, May 31, 2014

Infra-Red Timelapse

Having had my Canon 50D converted to IR and knowing that the 50D can deliver Magic Lantern Silent (DNG) Pictures, ie via LV with no shutter action, I thought I would carry out some experiments this weekend. 

Unlike ‘normal’ photography, IR photography is best undertaken in the brightest of bright sunshine, as we are capturing the reflected IR photons from the sun. Thus there are three sweet times to take images, not two: the golden hours of sunrise and sunset for ‘normal’ photography; and midday ‘golden period’ for IR.

Until the heroes at Magic Lantern tweak the Silent Picture mode, I’m a little limited to timelapses where the light doesn’t change drastically, like is does at sunrise or sunset. Timelapses taken when the light is changing by large amounts requires one to adopt the, so-called, holy grail technique; where you intervene in the timelapse taking and make exposure (step) adjustments.

Magic Lantern offers another approach, whereby you use Auto-ETTR. But, as the Silent (DNG) captured images currently don’t have any exposure EXIF data, I am limiting myself to timelapse sequences where the light is pretty much constant, ie I’m not using A-ETTR at the moment.

So far my workflow looks like this:

  • Focus and compose the camera; 
  • Put the camera in manual exposure and manual focus;
  • Use Auto-ETTR to set the ‘best’ exposure; 
  • Set the ML timelapse settings, I aim for 24 fps in the final video; 
  • Set Silent Picture mode to on; 
  • Put the camera in LV;
  • Start the capture sequence; 
  • Go and have a cup of tea; 
  • Move the DNG images on to the PC; 
  • Use EXIFToolGUI to put back in the missing EXIF data;
  • Create your video in LR/LRT.

The above may look complicated, but it is not. Also there are many refinements you can make. For me, LRTimelapse ( ) is a great companion to LR. In addition I recommend David Milligan’s Adobe Bridge script for deflicker (which works without EXIF data):
So the proof is in the pudding, as they say. So here is a simple (and rather crude) IR video that I made this afternoon. Clearly I need more experiments!

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