Why not always shoot HDR Video

D

DDirector

Veteran
With the Magic Lantern on my T2i there is an HDR function that I can turn on when shooting video.

Well, when should I use this, and when shouldn't I?
What are the Pro's and con's of using it?

I haven't used it yet, but if its great quality and easy to edit, then I dont see why I would be shooting normal mode when I can be shooting HDR videos to get a higher dynamic range.
 
i imagine it takes up a lot more space, too. i don't know much about it, but it's my understanding it composites three images together... so, three times as much space? And likely 1/3 of the low shooting time limit? 12 minutes or so isn't much of a problem, four minutes can get you into some trouble.
 
before 2.3stable release, it was two streams of video, so you loose around half the frame rate when you interpolate the hdr video together. Not sure if any advance has been done to it on 2.3. But you wouldnt use it day to day, especially at half the frame rate... unless you filmed it in 720 50/60p. It is alot of workflow fluff around , but i guess like anything, once you get the workflow down in post, you will save time.
 
To clear things up. Magic Lantern HDR alternates your ISO between two ISO's that you set, and it does it every other frame. So your odd frames would be say ISO 100 and your even frames would be ISO 800. You only get one video file, just like normal, but when you watch it, the flickers as it switches between ISO's. To use this video clip, you're having to split your video into two streams-odd frames and even frames, giving you two streams at half your original framerate. These two streams are then extrapolated back to your original framerate finally merged together taking detail from both. If you make a donation to Magic Lantern, even just $10, they send you a complete HDR package takes care off all the work with just one click. While automated, it takes quite a while to process the clips, and you have to do each one individually.

So what's it good for? Perhaps you've got an indoor scene against windows and you don't have enough light to bring up your indoor exposure. So you'll set one ISO for inside, and one for outside. I used it at a wedding recently when the newlyweds were coming out of the church. I had an indoor exposure, and an outdoor exposure, all in one shot and was able to follow them from inside the church to their car with no noticeable exposure change.

So what's the drawback? Processing time for starters. And due to the technique used to image the HDR, there can be some artifacting, especially on fast motion stuff. HDR, like anything else, is simply a tool that should be pulled out when needed, but it isn't something I'd do all the time.
 
thanks, great explanation!
so did you shoot hdr handheld at the wedding or were you waiting outside the church?
 
I was using my shoulder rig. I tracked backwards from inside with them, then pivoted behind them to their car. In this case, there was hardly an artifacts because I was essentially only using one exposure at a time. I was 800 indoors, then 160 outdoors. The only time that both exposures were used was during the transition from indoors to out.
 
Of course you can always shoot the same location as "clean plates" if you have exposure range problems can't handle directly. For example, shooting in a room with a very bright window visible with the subject. You can shoot a few seconds of the same shot exposed for the window, then shoot it exposed for the talent. In After Effects you can mask out the window and drop in the better exposed version.

If you're shooting locked off you can also snap a few pictures at different exposure levels and use those later in AE to correct underexposed or overexposed regions using the clean plates.
 
El Director said:
To clear things up. Magic Lantern HDR alternates your ISO between two ISO's that you set, and it does it every other frame. So your odd frames would be say ISO 100 and your even frames would be ISO 800. You only get one video file, just like normal, but when you watch it, the flickers as it switches between ISO's. To use this video clip, you're having to split your video into two streams-odd frames and even frames, giving you two streams at half your original framerate. These two streams are then extrapolated back to your original framerate finally merged together taking detail from both. If you make a donation to Magic Lantern, even just $10, they send you a complete HDR package takes care off all the work with just one click. While automated, it takes quite a while to process the clips, and you have to do each one individually.

So what's it good for? Perhaps you've got an indoor scene against windows and you don't have enough light to bring up your indoor exposure. So you'll set one ISO for inside, and one for outside. I used it at a wedding recently when the newlyweds were coming out of the church. I had an indoor exposure, and an outdoor exposure, all in one shot and was able to follow them from inside the church to their car with no noticeable exposure change.

So what's the drawback? Processing time for starters. And due to the technique used to image the HDR, there can be some artifacting, especially on fast motion stuff. HDR, like anything else, is simply a tool that should be pulled out when needed, but it isn't something I'd do all the time.
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I would love to see the final footage you shot for this, even an example.... Sounds very interesting

Thanks
 
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