Vehicle roof as grey card?

[LandyShooter]

Hi all,

Is this a crazy or stupid idea?

I'm mostly filming, but also some photos with a A6600/A7C and two more of the new cameras that are coming out this year, with a large variety of lens from the 200-600 to the 10-18 and macros etc. I use a lot of action cameras as well, DJI Osmo Actions on auto everything.
I am in Africa outdoors most of the time. Deserts, green grass areas or jungle. It is either brutally sunny, overcast, raining or early morning/late evening.

One of the issues I have is white balance and over exposure of white in shots (camera always set to auto (EDIT: Auto WB) as most of my subjects appear and disappear within 5-20 seconds as does the lighting conditions (eg: tree shade/open sunny area).

Many of my shots have me or my vehicle in them. The vehicle has a white roof, so when editing in FCP later it is always overexposed, the rest of the shot under exposed as I use a ND4 filter most of the time, then just raise the highlights exposure in FCP. There is usually no other white apart from clouds in any of my shots, very few true blacks either in the desert.

If I were to paint the roof & roof tent of my vehicle grey, this would solve the over exposure of the white roof problem to a large degree. My question is, could I paint it somehow to be grey like a 18% grey card/colour checker card? Then I can always use it as a constant reference for white balance?

Is there any merit in that as an idea? Assume there will be something I don't understand that means it wouldn't work for white balance, but thought I'd ask!
If it is worth doing, how do I know what shade of grey to use?

Cheers, Darrin

https://www.youtube.com/@roamingyak

Picture: roof tent white is clipping above 100% on Luma, rest of the shot is underexposed.

 

[Gaz]

Hi all,

Is this a crazy or stupid idea?

I'm mostly filming, but also some photos with a A6600/A7C and two more of the new cameras that are coming out this year, with a large variety of lens from the 200-600 to the 10-18 and macros etc. I use a lot of action cameras as well, DJI Osmo Actions on Auto.
I am in Africa outdoors most of the time. Deserts, green grass areas or jungle. It is either brutally sunny, overcast, raining or early morning/late evening.

One of the issues I have is white balance and over exposure of of white in shots (camera always set to auto as most of my subjects appear and disappear within 5-20 seconds as does the lighting conditions (eg: tree shade/open sunny area).

Many of my shots have me or my vehicle in them. The vehicle has a white roof, so when editing in FCP later it is always overexposed, the rest of the shot under exposed as I use a ND4 filter most of the time, then just raise the highlights exposure in FCP. There is usually no other white apart from clouds in any of my shots, very few true blacks either in the desert.

If I were to paint the roof & roof tent of my vehicle grey, this would solve the over exposure of the white roof problem to a large degree. My question is, could I paint it somehow to be grey like a 18% grey card/colour checker card? Then I can always use it as a constant reference for white balance?

Is there any merit in that as an idea? Assume there will be something I don't understand that means it wouldn't work for white balance, but thought I'd ask!
If it is worth doing, how do I know what shade of grey to use?

Cheers, Darrin

https://www.youtube.com/@roamingyak

Picture: roof tent white is clipping above 100% on Luma, rest of the shot is underexposed.

You know they can do vinyl wrap these days. Get yourself a vinyl wrapped panel in grey, matchy matchy. Your bonnet?

 

[Brownie]

You can use anything that's 18%-ish grey, but if the sun is out and bright and you're shooting a vehicle roof, there's going to be glare or bright spots that will affect the balance. Also, you should be at 90 degrees and the grey needs to fill the frame. Sounds like more of a hassle than anything. And if it's raining, how is that going to work?

Also, the white roofs are meant to reflect sunlight, and therefore heat. Painting them grey is going to make it a lot hotter in the vehicle.

If I were you, I'd learn how to use P mode instead of Auto and shoot in RAW. You'll get a lot more out of the shots and can make white balance adjustments in post if need be. Buy a foldable grey card on amazon.

If you decide to go this route, take a grey card to a paint shop and have them use a spectrum analyzer to match it.

 

[LandyShooter]

Thanks. Wrap is not much of an option in Africa or for a bush vehicle.
Heat isn't much of an additional problem, its stinking hot even with a white roof ;-)
But the roof rack takes most of the sun and there is huge gap for airflow. And then the inside of the roof is lined with 3 layers of sound proofing plus fibre glass lining, so not too concerned about noticing any difference there...

I use the existing white roof sometimes to set the WB in FCP - hit and miss, sometimes great, sometimes good, sometimes laughable ;-)
Issue is usually that it's dusty/dirty so not true white or overexposed in the shot and thus FCP rejects it.

 

[FowlersFreeTime]

What about using an exposure disc instead?

ExpoDisc Professional White Balance Filter: Save Time Editing Color

The ExpoDisc v3 Professional White Balance Filter is a fast, easy-to-use tool to set an accurate custom white balance. Every ExpoDisc is assembled and tested in the USA.

www.expodisc.com

 

[Landshark99]

the only issue i see with painting the roof or hood 18% grey is the paint should be flat and the specific 18% grey type paints I would not think be made in auto paint, but if you do not care about it being an auto paint, why not

 

[LandyShooter]

What about using an exposure disc instead?

ExpoDisc Professional White Balance Filter: Save Time Editing Color

The ExpoDisc v3 Professional White Balance Filter is a fast, easy-to-use tool to set an accurate custom white balance. Every ExpoDisc is assembled and tested in the USA.

www.expodisc.com

Thanks, I have never heard of this. Is it cheap and gimmicky or used by pro's etc?

 

[FowlersFreeTime]

Thanks, I have never heard of this. Is it cheap and gimmicky or used by pro's etc?

I bought one recently, but haven't had the chance to use it. I will report back when I do.