monitoring critical exposure - best practice

[Martin Konrad]

I would love some input about your setups.

I recently had a tabletop studio setup with very hard lighting (direct backlight into glass/moving object)
My standard setup is a studio monitor with waveform to judge exposure.

But the waveform is always based on one channel and in this setup I noticed 5 of the 6 channels I could choose to be fine (max 85-90)
but the blue channel clipping (around 105)

We test recorded a clip and the scopes in CineX show a flat top/clipping for all 3 channels (red/green/blue)

I presume its most often the blue channel that clips first (sky/hmi spectrum...) but If you can share your findings

I think I will from now set my monitor to histogram plus waveform and chose the histogram thats furthest right (red/green/blue) to determine the
waveform channel I watch.

 

[Phil Holland]

If we are talking RED cameras I would recommend strongly in investigating and getting used to the In Camera Exposure Tools as they are tied into exactly what the camera and sensor are doing.

Specifically look into Exposure Check, Video Check, GIOSCOPE.

The Exposure Monitoring Tools like the "Traffic Lights" and Histogram are also very important.

The Traffic Lights in particular will notify if you are clipping. GIOSCOPE does a nice job of identifying potential clipping areas, even smaller ones as they might trail off into specular overexposure if you are trying to be super critical.

The channel that clips first is mostly dependant on the light source and the potential color of an object in frame that could be clipping. Truly depends on each situation.

 

[Martin Konrad]

thanks Phil,

I am well aware of the in camera solutions. But I do believe the Traffic lights come on at 2% of the channel clipping, not sure if they
will be on if its only one small highlight. They are also more difficult to observe from further away while setting the backlight, so the setup requires an
extra person (unfortunately not always possible) or a roundtrip (set light - go back to camera and watch exposure - adjust light - back to camera...)

Ideally on an external monitor I can watch the effect of the light "live while setting/adjusting" and judge its exposure... Its a big plus if there are
lots of shots in a day with a small(ash) crew.

 

[Phil Holland]

thanks Phil,

I am well aware of the in camera solutions. But I do believe the Traffic lights come on at 2% of the channel clipping, not sure if they
will be on if its only one small highlight. They are also more difficult to observe from further away while setting the backlight, so the setup requires an
extra person (unfortunately not always possible) or a roundtrip (set light - go back to camera and watch exposure - adjust light - back to camera...)

Ideally on an external monitor I can watch the effect of the light "live while setting/adjusting" and judge its exposure... Its a big plus if there are
lots of shots in a day with a small(ash) crew.

Give GIOSCOPE a try and toggle on the colors you desire, the red color which fades to black at full clip is incredibly useful for spotting tricky situations during setup. A hot key to toggle the feature makes it quicky to use.

 

[Björn Benckert]

thanks Phil,

I am well aware of the in camera solutions. But I do believe the Traffic lights come on at 2% of the channel clipping, not sure if they
will be on if its only one small highlight. They are also more difficult to observe from further away while setting the backlight, so the setup requires an
extra person (unfortunately not always possible) or a roundtrip (set light - go back to camera and watch exposure - adjust light - back to camera...)

Ideally on an external monitor I can watch the effect of the light "live while setting/adjusting" and judge its exposure... Its a big plus if there are
lots of shots in a day with a small(ash) crew.

The GUI tools are the only you can trust as every thing downstream is reading the raw with metadata so even if you are hooking up a SDI monitor, all you are watching is the raw file + added meta data. So depending on those setting the SDI monitor will show or not show clapping. So if you want another monitor on set, just make sure the GUI is overlaying the image so you see it even if you run around and adjust your lamps your self.

Give GIOSCOPE a try and toggle on the colors you desire, the red color which fades to black at full clip is incredibly useful for spotting tricky situations during setup. A hot key to toggle the feature makes it quicky to use.

Agree think the gioscope toggle should be default next to zoom in 1:1 on monitor.

 

[Martin Konrad]

Thanks Björn, I will definitely set up a shortcut for the gioscope. The external monitors scopes are of course based on raw + color and gamma settings + lut but that should give me a clipping on the external scopes before the actual raw is clipped as raw + color/gamma and lut should be more contrasty than the sensors raw.
I guess I will run a few tests on a quiet day testing traffic lights, gioscope and external scopes in daylight and hmi setups and see which system works best in my setups.