Posted on 17. Jul, 2013 by planetmitch
Yesterday we broke the news that Magic Lantern has “improved Canon EOS 5D Mark III dynamic range to 14 stops!”
Well, now there’s a sample video showing you the advantage. As Michael Anthony posts in the description, he’s set this up as a possible “worst case scenario” so your results should be better.
Normal Raw vs Dual ISO Raw
A test of the new Magic Lantern feature "Dual ISO" in raw video mode. magiclantern.fm/forum/index.php?topic=7139.0
This is not a scientific test but just rather something to give people an idea of the quality improvements to Raw video using this new feature.
Testing methods used…
Camera: 5D Mark III (shot 24fps at 1080p)
Dual ISO was set to use 100 and 1600 ISO.
Footage was shot in a dimly lit room with both a tungsten lamp and dark areas in the frame.
Shot handheld to reveal any moire or aliasing which may increase using Dual ISO feature.
Raw was converted to DNGs using the newest rawtodng.exe.
Postprocessing via Adobe Camera Raw using identical settings for both Normal Raw and Dual ISO shots…
Exposure was brought up a bit to +2.8
Noise Reduction 0,
All other settings were at 0 or default values
Exported via After Effects to intermediate AVI files (Cineform 444 Filmscan 1)
This test was designed to be a worst case scenario. Bright light in a dim room room including fabric textures to help reveal moire. The reduction of shadow noise is dramatic to say the least. Without Dual ISO the footage would have been unusable. But it does come at the cost of increased moire/aliasing, something which Alex from Magic Lantern clearly indicates in his technical documents describing the new feature. Clearly, many scenes won’t exhibit the level of moire/aliasing shown in this test, so one just has to be mindful of the content of your scene and weigh that against the need to retain both highlight and shadow information when the dynamic range of the scene if greater than 12 stops. But when you are unable to properly light a scene to even out the exposure, the Dual ISO feature allows you to bring up the shadows in post significantly with very little increase in noise. Regarding any minor resolution decreases that are supposed to accompany this feature, I think that is a moot point… the footage wouldn’t even be usable in my test scenario without the Dual ISO feature (short of lighting the scene properly). I’m sure in many typical usage scenarios, the benefits will far outweigh any disadvantages.
Thanks to Alex from Magic Lantern for all his generous work and contributions. Greatly appreciated.
(cover photo credit: snap from the video)