Zebras

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Patrick Acum

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  • Joined: Mon Mar 17, 2014 5:13 pm

Zebras

PostSat Apr 01, 2017 1:41 pm

There seems to be a bug with zebras on the ump pro.
With the viewfinder attached, I can scroll through the zebras and see them adjust in the viewfinder, so more appear as I go from 100-75, as expected.
On the LCD however, whether I adjust on the touch display or through the menu, the zebras appear to be stuck on 100, no change at any setting. I've checked the monitoring outputs and they're the same, which is weird.
Also, if turn on both the output from the camera and the zebras in the vf, you can see two sets overlapping, one at 75, one at 100, which could be useful, if a little annoying.
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Patrick Acum

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Re: Zebras

PostSat Apr 01, 2017 1:48 pm

Think I can see what it is.
Zebras from the camera seem to be showing pre lut, whether a lut is enabled or not.
Zebras in the viewfinder are showing post lut, if I toggle the lut on and off in camera, I can see zebras appearing in both positions.

But the lcd only seems to display 100, regardless of what's selected. The viewfinder ones change as you adjust on the body, but the lcd stays the same, unless Im pointing at the sun, the zebras barely appear whatever the setting.
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Patrick Acum

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Re: Zebras

PostSun Apr 02, 2017 9:22 pm

After more playing, it seems that if the zebras are set to 75 on the camera and switched on in the viewfinder, these show up in reference to the lut being used, (if you toggle the lut on and off at the camera end, the zebras come and go in the viewfinder)

On the lcd, the zebras always show white clip only of the underlying log regardless of how you set the percentage - you can see this if you turn on false color and scroll though the zebra percentages, they don't seem to make any difference on the lcd, and if you toggle the lut on and off, they don't change either.

If you set the zebras to say 75 (its where Im used to seeing them coming from a digibeta background!) AND switch them on in camera and in the viewfinder, you'll now see the 75 on your rec709 lut (BMD film-video) so you know exactly where your faces should be AND you'll see another set of thicker zebras which show where your underlying log is clipping. Brilliant! Best of both for me!

Coming from sony f5/55, the sony guru Alister chapman liked to set a 709 lut in the viewfinder and expose from that on the hoof, the rationale being that if your 709 was safe, the log would easily be safe. The down side of that being you're potentially throwing away range as the 709 lut would clip before the log, so you'd err on the side of caution.

This set up tho, seems to give both, you can use a nice contrasty 709 lut for exposing the middle bit where your faces are and its easier to focus from, yet you have an idea of whats happening underneath. Of course, if you're in a set up where you can keep flicking in false color, that shows you exactly what the log is doing over the full range, so that would clearly be the best solution. Quite often tho for me, I'll be on someone's shoulder where things are unfolding in front of or I might be going thru some dynamic lighting changes, so that's not possible.
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Dave Perry

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Re: Zebras

PostFri Dec 01, 2017 4:05 am

Very helpful info Patrick. I was just trying to determine the differences in zebras on the LCD versus in the viewfinder. I typically shoot film log color with no display lut. Some clients don't like what they see in the director's monitor but I assure them it will look great when colored in post. I'm so used to working that way and exposing for log. However, I want to start using a display lut on set so the director or client can better see what the image will look like.
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