Slow-Mo Sodium Vapor?

[Barry Green]

HVX is a CCD and is as such immune to rolling shutter issues. Film works fine at 1/48 as well. The question David's asking is does the rolling shutter introduce issues above and beyond what we had with film. I'll try to remember to test this out tomorrow.

 

[Steve Freebairn]

Under Kino lights, the Red is fine at 1/48th at 24 and 23.98, under crappy fluorescents, you'll get an image that has some bars like the image a few posts ago.

 

[Policar]

Under Kino lights, the Red is fine at 1/48th at 24 and 23.98, under crappy fluorescents, you'll get an image that has some bars like the image a few posts ago.

Well kinoflos have electronic ballasts so they should be fine for anything.

That 60hz sources don't work with Red is definitely problematic. I did a lot of shooting with the HVX recently and found 1/48th to work fine with everything. I don't see why a rolling shutter would introduce new flicker, particularly since film has its own sort of rolling shutter and works fine... If 2.5 pulses exposes each frame the same, why would it expose differently on a rolling shutter?

Oh well, though. Not the end of the world.

 

[Dj Joofa]

Under Kino lights, the Red is fine at 1/48th at 24 and 23.98, under crappy fluorescents, you'll get an image that has some bars like the image a few posts ago.

Did you try 1/60 and 1/120 at 24 fps with the florescent light?

 

[Dj Joofa]

If 2.5 pulses exposes each frame the same, why would it expose differently on a rolling shutter?

For a rolling shutter camera the flicker can manifest itself as "banding" even in a single image (please see the image in one of my posts above), and perhaps is what is observed by kinobarin when operating the camera at 1/48 seconds exposure time at 24 fps with florescent lights. This happens because the integration for each row happens at a different time, and is not a question of 2.5 pulses.

Unless the integration time is derived by the forumlas I listed in my posts above you may see banding from flicker even on a frame by frame basis.

In addition, there is another issue to consider -- blanking. Video cameras make it even more complex than film, because of the vertical blanking. If the vertical blanking is not properly adjusted then even that banding per frame moves up and down on each frame (phase change per frame) and becomes more nauseating.

 

[Mitch Deoudes]

Joofa - was your test frame shot on the Red, or another camera? Could you detail your setup for the shot (lighting, shutter speed / framerate, etc.), for inquiring minds?

Barry - interested in your test results, when you've got them.

 

[Dj Joofa]

Joofa - was your test frame shot on the Red, or another camera? Could you detail your setup for the shot (lighting, shutter speed / framerate, etc.), for inquiring minds?

Barry - interested in your test results, when you've got them.

We have done several tests under flickering lights; none of them with Red. I can't post our own internal images. That image that I posted was not done by us. To provide a quick illustration of how flicker can cause "banding effects" even on a single frame when the exposure time was not matched with line frequency, I pulled that image out of an academic publication, but most certainly it was not done with Red. I have to go back to the publication to see the values they used.

 

[radiant]

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