... I am trying hard to understand Manual settings and I can see the results look pretty good once I get a EV 0.0 right, but Is my basic workflow right?
... I really don't know when to adjust aperture vs. shutter speed.
OK ... if you truly want to learn you need to invest some time to read & then reach some level of understanding ...
First of all follow below link to a short tutorial about the most important tool we have to get the exposure correct ... the histogram. (you have it in the GO 4 app)
Using a Histogram in DJI GO 4
If you now understand how to interpret a histogram go on and activate it in GO 4. And when you are in that menu also activate the "Overexposure warning" (high lights totally white beyond recovery in post), that will quickly help you see directly in the camera view where you are over exposed by a "black & white" striping.
So now you have the exposure tools visible in GO 4 & ready to aid you setting the correct exposure ...
How to change the exposure & why use this but not that ...
You have three parameters to regulate how much light entering onto the sensor ...
1. Shutter speed
2. Aperture
3. ISO value
Pros & cons and side effects by using the above in the same order.
1. Shutter speed:
A slow (or longer opened) shutter let more light enter into the lens, so if the picture are to dark a slower shutter will make it lighter. The side effect is that you run greater risk to get a blurry video or picture depending on either you (the drone) shake or the pictured object moves. You can find various guidelines on WWW on how fast shutter you need in order to "freeze" different moving objects.
2. Aperture:
A larger aperture (smaller aperture number, yeah I know it feels turned around but that is how it is) will let in more light & the opposite less light. The side effect is the depth of field ... with a small aperture number (more light in) generates a short depth of field. And a large number (less light in) give you a longer depth of field. Depending on the lens the depth of field goes infinite above a certain aperture number (to know on which aperture value that happens you need to dig into more fact regarding the lens & know the focal distance). One more thing lens & aperture wise is that most lenses are softest (less sharp) usually on the largest & smallest aperture values (that's why you heard that A5,6 is to prefer). But really this is if you are pixel peeping.
3. ISO:
A low ISO number makes the sensor less sensitive to light (makes the picture darker) ... & of course the opposite makes the sensor more sensitive & the picture lighter. The downside here is that a high ISO value generate noice, how much & how ugly it is depends on the sensor. The noice is usually most visible in the darker parts of the picture.
So that's the three parameters that effects the amount of light the sensor can react on, and what you can use to position the graph in the histogram correctly.
So when to use what combinations ... let's try with 3 user cases.
1. Sunny daylight, shooting a landscape without fast moving objects.
ISO value as low as possible to start with as enough light probably exist & you want to minimize the introduction of noice.
Use a larger aperture number in order to maximize the depth of field (everything should be in focus in landscape shoots)
The shutter speed can be as slow there after as it must be to get the histogram correct as it's no moving objects to freeze in the picture besides the movement of the drone (camera) itself.
2. A closeup picture on a fast moving object under a dark clouded sky.
As you have a fast moving object to somewhat freeze we have to start with the shutter, it needs to be so fast so the object clearly can be sharp.
I should then choose a pretty small aperture number in order to let in as much light as possible due to the fast shutter.
Last in the line are then the ISO value ... it will then be what it must be in order to get the histogram correct. Hopefully the choice of a smaller aperture number have let in enough light so you don't need to crank up the ISO to much and by that avoided noice in the picture as much as possible in order to get the moving object "frozen".
3. A low light shoot (night shoot) in shaky conditions (flying your drone in windy conditions).
Well ... by experience I know that shutter speeds longer then 1,5-2 sec. will make the picture blurry due to the drone moving, I try with as short shutter I dare.
Then as small aperture number as possible to let in maximum of light and by that minimize the need to raise the ISO value to much as that certainly will generate noice in this darker night picture.
Now perhaps you have a clue how things work regarding the 3 exposure parameters & the histogram tool.
An extra tip to avoid noice ... practice "exposure to the right". This means that you try to lighten up the highlights in the picture to the verge of being blown out to pure white. The mountain graph in the histogram will be pushed to the right side as much as possible but without cutting through the rightest side in the histogram without going down just before crossing the side wall of the histogram. The picture will look to bright but now you have also brighten up the darkest parts in the picture thus minimized the introduction of noice there. In post you the darken down the picture to a correct level. By this method you have minimized the risk of noicy shadows.
Now perhaps you feel that all above is biased towards mostly stills ... but actually it's mostly the same for video. The thing with video is that the light conditions constantly change so you need to choose some middle way or plan more clips and group the shoots for the exposure needs & then join the clips to a full video in post rather than filming everything in one turn.
One thing is a bit special when it comes to video ... motion blur.
To get a natural looking video you should consider the factor of introducing an amount of motion blur. But for drone flying this is only relevant from approx. 30 meter altitude and below ... higher then that you will not notice motion blur anymore.
In video you usually regulate the motion blur with the shutter in relation to your chosen frame rate. The rule of thumb is to double the frame rate as shutter speed. For instance if you use 24 fps gives 1/48 sec. & 30 fps gives 1/60 sec. This is not exact science, can differ depending on distance to your object or in what direction you fly in relation to the object.
So with use of this rule you in a sense lock the use of shutter speed to regulate the amount of light entering the sensor ... left are aperture & ISO to get the exposure correct (histogram correct) & to avoid noice from a high ISO value you try to have that as low as possible & left are the aperture to nail the final correct exposure.
If you understand all this you have all possibilities to understand how to handle different situations both when it comes to stills but also video (even though video adds even more components beside exposure ... story line, smooth drone operation & sound).
Good luck!
