Custom white balance

[Bill Lazar]

I am converting one of my Mavic 4 Pros to full spectrum. I will be able to take infrared images with the appropriate filter. On my regular camera, I can take a picture of a grey card to use it for custom white balance when taking iR images, so that I can visualize the result more accurately. I would like to be able to do this on the drone. I see that you can set temperature and tint, but see no way to set a custom white balance. The manual does not even mention white balance. A Google search brings up plenty of instructions saying to use the eyedropper to choose a color from the camera or to choose an image to use for custom white balance. But I see no way to do this.

Does anyone know anything about this?

Thanks.

 

[JeffreyS]

Bill, if you shoot in RAW and just use AWB on the M4P. then you determine the WB you want in ACR or LR post. You have more control of it that way. And I don't think you can set a custom WB in the drone. I wouldn't even if it was a feature.

 

[Bill Lazar]

The advantage of custom WB is that you get a better idea of the composition in real time.

 

[Ralph thompson]

Just a thought, could be wrong, surely IR has no colour temperature. Depending on the IR frequency band width, you add faux colour to provide a certain type of image but the visual colour spectrum doesn’t exist outside the visual colour range. Just my thoughts, not an expert.

 

[Dave Maine]

IR does have a color temperature. It is down below what the average eye can see at the red end of the visual spectrum that we can see. You need a very long exposure to capture it depending on the camera setup. On my Nikon with a 57 filter it takes 30 sec to capture an image, which results in a very red image. I don’t know of any way to see it in real time as you fly.

 

[Dogpilot]

Actually doing a custom white balance is very important in IR photography. Usually, you can use green vegetation as a reference, since it reflects strongly in IR. If you do UV photography, you can use teflon pipe tape as a reference image. I had the issue with the M2P I converted, but it didn't have a custom setting either. Kind of had to wing it in raw. Depending on which look you are shooting for, I usually discard color information. I am using it for geological structural analysis. If you want to do the effects, like Goldie or others, then your going to have to play in Camera Raw for a bit adjusting the color balance after the fact.

 

[Ralph thompson]

Interesting. As a photographer, it is important to set WB in the visual spectrum even when using raw capture. By not setting WB you are liable to clip a single colour channel so that when you make colour corrections in post, you will end up with a colour cast. A rule of thumb is if you can’t find a neutral surface to set WB, just use the palm of your hand. However as per OP, this does require the ability to set custom WB.
Dogpilot I like your signature phrase. An FAA pilots monthly safety newsletter, circulated to all NA registered pilots, (now defunct) attached a phrase below the title, ”a pilot will never live long enough to learn from his mistakes”.

 

[Dogpilot]

IR photography is a bit tricky. Personally I have three IR cameras, one being actually full spectrum. The clipping is actually a good thing as the red channel tend to be overwhelmed on one side or if your doing UV, blue on the other. So centering it is always best. I actually didn't like the result with the M2P, images were too fuzzy to be useful. I was more interested in the UV range for carbonate rocks. Atmospheric backscatter tended to really overwhelm the images. I think the lenses I the drones are not necessarily great for full spectrum as it seems the focus shift you get in IR or UV is hard to correct.

It is true, seldom do pilots get to learn from their mistakes. I was fortunate. As a Navy pilot I got placed in the test program and did my masters in Aviation Safety. I had the delightful experience of actually crashing 3 aircraft, 5 complete engine failures, one in a twin, onboard explosions in the E2 Hawkeye and an exploding engine off the catapult in the Med. I was one of those exceptionally lucky pilots. Doesn't always work out for many. If your bored this Xmas day you can read this article on the explosion in the Med:
My First Awful Experience

 

[Ralph thompson]

You should buy a few lottery tickets, sounds like Lady Luck is on your side.

 

[Dogpilot]

Well the only lottery I won was the draft lottery. Kind of why I took the NROTC scholarship. Since I could make it up a flight of stairs and count how many fingers the flight surgeon was holding up, they sent me to fight school. They figured 80% get attrited, they sent all of us that could pass the physical to Flight School. They were kind of short on pilots. My commanding officer of the facility I did test flying at, not a pilot but an engineer. He asked, "why do you keep bringing back these broken burning hulks and not jump out?" "Skipper have you seen how I have to bail out?" "The pilot never lives." I had to waddle down a narrow corridor, wearing a parachute, raft strapped to my butt wearing an O2 system. "Who is flying while I doing this?" Not like stuff was going swimmingly well at that point. I actually still hold the record of emergency landings at North Island. I have over 100 field arrestments, a field centurion. Dubious honor.