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Exposure Settings

Has anyone worked out exposure settings using an external light meter and a gray card?
Interesting question. Not to deflect from your original question, but I find that (on a sunny day) ground exposure can be as much as a full stop darker than my aerial exposure. This is obviously due to the sun reflecting off so many ground surfaces like concrete, lighter colored roofs, etc. So obviously if I set exposure in the shade (like under a tree), all that goes out the window once I'm airborne. Even worse, exposure while in the air can change as much as .7 stops by simply turning the camera 180°. So I gave up on setting exposure while on the ground a long time ago. I find the EV meter gets me well within the ballpark. That said...

I generally find that slightly underexposing (video) is much easier to work with in post than slightly overexposing (for obvious reasons). A normal 5 minute flight's exposure can range from EV -0.3 to EV -1.0. On a partly cloudy day exposure has gotten as low as EV -1.7 with acceptable results. When you're dealing with over a stop of exposure range while in flight, it seems setting EV on the ground is all but pointless. Just my 2 cents.

D
 
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Interesting question. Not to deflect from your original question, but I find that (on a sunny day) ground exposure can be as much as a full stop darker than my aerial exposure. This is obviously due to the sun reflecting off so many ground surfaces like concrete, lighter colored roofs, etc. So obviously if I set exposure in the shade (like under a tree), all that goes out the window once I'm airborne. Even worse, exposure while in the air can change as much as .7 stops by simply turning the camera 180°. So I gave up on setting exposure while on the ground a long time ago. I find the EV meter gets me well within the ballpark. That said...

I generally find that slightly underexposing (video) is much easier to work with in post than slightly overexposing (for obvious reasons). A normal 5 minute flight's exposure can range from EV -0.3 to EV -1.0. On a partly cloudy day exposure has gotten as low as EV -1.7 with acceptable results. When you're dealing with over a stop of exposure range while in flight, it seems setting EV on the ground is all but pointless. Just my 2 cents.

D
I usually have to make corrections in post
 
Interesting question. Not to deflect from your original question, but I find that (on a sunny day) ground exposure can be as much as a full stop darker than my aerial exposure. This is obviously due to the sun reflecting off so many ground surfaces like concrete, lighter colored roofs, etc. So obviously if I set exposure in the shade (like under a tree), all that goes out the window once I'm airborne. Even worse, exposure while in the air can change as much as .7 stops by simply turning the camera 180°. So I gave up on setting exposure while on the ground a long time ago. I find the EV meter gets me well within the ballpark. That said...

I generally find that slightly underexposing (video) is much easier to work with in post than slightly overexposing (for obvious reasons). A normal 5 minute flight's exposure can range from EV -0.3 to EV -1.0. On a partly cloudy day exposure has gotten as low as EV -1.7 with acceptable results. When you're dealing with over a stop of exposure range while in flight, it seems setting EV on the ground is all but pointless. Just my 2 cents.

D

In still camera photography, the method for setting exposure is fairly well known.

The Sunny Sixteen Rule is the simplest. There are three factors. F Stop, Length of Exposure and rated ISO Setting (Which used to be the speed of the film). On an average sunny day with an average scene in front of you, with an ISO Setting of 125 the F Stop will be F16, the Shutter Speed will be the reciprocal of the ISO 1/125. This will change if in a brught desert or a dark forest.

Then you have a Gray Card. It will reflect 50% of the light on its surface. You can use a camera in Manual Mode to get the settings and then dial them in or you can use a lightmeter to do the same.

Then there is the Zone System. It is based on film or paper having an exposure width of 11 'Zones'. Zone 5 is the Middle Gray, 1 absolute black and 10 absolute white. Zones 1-4 and 6-9 will show detail accordingly. Using a 1 degree spotmeter, I can predict the highlights and shadows and what the image will look like and make that image over or under exposed as I desire. Modern digital cameras might have far more latitude, but the prinipal is the same.

All the EV+/- does is shift the settings up or down. Manually doing that shift will have the same effect.

What I was searching for, is a way to dial in exposure for a flight based on readings I achieve and then the camera manually to that reading.

Your example of ground vs shadow settings is correct. ANd looking at the opposite scene. Also, underexposure is favored as it will contain detail the overexpsoure will not.

"A Stop of range ... " that would depend on the range of the sensor to record shadow/highlights.

I would also be interested in finding the "Sweet Spot" of the sensor.
 
Agreed. My point was that correcting slightly underexposed is easier than correctly slightly overexposed.

D
It appears my X5 camera, the sensor has four stops above and below the median stop.
Using ISO, the lowest would be 100, median is 1600 and max is 25,600. A nine stop range.
 
It appears my X5 camera, the sensor has four stops above and below the median stop.
Using ISO, the lowest would be 100, median is 1600 and max is 25,600. A nine stop range.
Beware that ISO 800 is the highest usable ISO for night footage. 1600 is way too noisy.

D
 
In still camera photography, the method for setting exposure is fairly well known.

The Sunny Sixteen Rule is the simplest. There are three factors. F Stop, Length of Exposure and rated ISO Setting (Which used to be the speed of the film). On an average sunny day with an average scene in front of you, with an ISO Setting of 125 the F Stop will be F16, the Shutter Speed will be the reciprocal of the ISO 1/125. This will change if in a brught desert or a dark forest.

Then you have a Gray Card. It will reflect 50% of the light on its surface. You can use a camera in Manual Mode to get the settings and then dial them in or you can use a lightmeter to do the same.

Then there is the Zone System. It is based on film or paper having an exposure width of 11 'Zones'. Zone 5 is the Middle Gray, 1 absolute black and 10 absolute white. Zones 1-4 and 6-9 will show detail accordingly. Using a 1 degree spotmeter, I can predict the highlights and shadows and what the image will look like and make that image over or under exposed as I desire. Modern digital cameras might have far more latitude, but the prinipal is the same.

All the EV+/- does is shift the settings up or down. Manually doing that shift will have the same effect.

What I was searching for, is a way to dial in exposure for a flight based on readings I achieve and then the camera manually to that reading.

Your example of ground vs shadow settings is correct. ANd looking at the opposite scene. Also, underexposure is favored as it will contain detail the overexpsoure will not.

"A Stop of range ... " that would depend on the range of the sensor to record shadow/highlights.

I would also be interested in finding the "Sweet Spot" of the sensor.
I think you misunderstood. I don't adjust the EV "knob" per-se. I READ the EV value via the DJI apps, and then accomplish proper exposure through manual setting of ISO, shutter speed and aperture - which is easy for photography, and more difficult for video. Honestly, still photography is a cake walk compared to the dynamic lighting conditions we have to endure in video. With photography, one can achieve excellent low-lighting results with even the most mediocre camera. My Mavic Pro - arguably my worst camera - turns out great stills using RAW + bracketing - regardless of lighting conditions. Same can't be said for video. For low light night *video* I have to use my X5 (my best aerial camera at this time) with the widest aperture (f/1.7 if memory serves). So....

As I stated earlier, I don't even bother fine-tuning exposure values on the ground. I ballpark it on the ground and then fine-tune it while in the air, taking into consideration constantly-changing, dynamic lighting conditions.

Regarding "zones," you nailed it. They produce an "average." A white roof can raise the overall average, which can underexpose the rest of the composition. And for this reason the Histogram becomes my best friend.

I agree with everything you said sans the remark regarding "using EV to shift settings." I do the opposite. I shift ISO, Shutter and Aperture to adjust the EV value.

D
 

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