Use HDR video to simulate iris pulls

[3pointedit]

The title pretty much sums this up.

where HDR is traditionaly used to expand the range of an image (at any moment) I propose using the extra dynamic range over time. The idea is to shoot 2 exposures at once so that you can mix from one to the other as required.

For example, when the camera moves from outside to inside, you rely on the DSLR to gauge exposure. Why not select the right place to perform the ISO change in post? That is split out the frames into 2 discreet streams of light and dark, sync them up and mix when you want to.

I am using 720p 50fps footage which means that resolution suffers but you retain the temporal detail with a much closer match. If the mix is quick you may not notice any misregistration at all.

*Video may not be live yet

I guess you could also perform advanced grading with some power windows, that is matte in the correctly exposed areas as required. For example when shooting a  person against an over exposed window, where you would normally use a grad filter.

[a1ex]

Offtopic: there was an iris pull feature in old ML, but I don't think anyone noticed it or knew what it does

[3pointedit]

Hmm, yes was that an actual iris pull like the focus pull with preset stops?

I like to manipulate in post, that's why I like this one. Certainly it would be much more usefull if the digic investigation ever opens up White Balance swapping too.

[a1ex]

Yes, it was with discrete aperture stops. Flickered a lot, but probably with some postprocessing could be usable.

Now that aperture can be moved in 1/8-stops and ISO can be altered every frame, I think it's technically possible to do a better implementation.

[3pointedit]

That sounds cool. I wonder if, with ISO changes to smooth out the aperture, you could ramp the pull with a bezier ease in/out?

[a1ex]

Yes, the exposure curve shouldn't be a problem, ISO can be ramped in very fine steps.