The f stop range of the lens most likely ranges from f2.8 when it’s fully wide open to something like f16 when it’s closed down as much as possible. The higher the f stop, the greater the depth of field (i.e. the more that is in focus). However the “sweet spot” optically of a lens is in its middle f stop range - 5.6 being pretty optimal. There would be nothing unique about the lens on a drone that would allow it to deviate from this mathematical truth. That being said, for most drone work, with the focus close to infinity, it shouldn’t really matter what the f stop is. If the footage does not look good, it’s probably for some other reason than f stop setting.
I think this deserves some further explanation, though your basic principles are generally correct.
The
M2P aperture range is F2.8-F11. The sensor is so small however that DOF is not really an issue - at F2.8 you are already getting DOF equivalent to F8 on a full frame camera - by F4 you are getting DOF equivalent to F11 on a full frame camera, and so on. On top of this, the nature of drone flight usually means huge distances between the drone and the scene, so if you have focused properly, everything is going to be in focus all the time. At F4, once you're about 60 feet in the air, everything from 3 feet to infinity is going to be in focus. Unless you're flying extremely close to something, DOF on drones is for the most part a non-issue. The combination of huge DOF, a wide angle lens (28mm equiv.) and large subject distances ensure that you can have everything in focus pretty much all the time on a
M2P.
A lens' sweet spot is entirely dependent on the individual lens, and that does not take into account sensor size or sensor resolution, both of which are very important variables to the resulting image quality. On a MTF test bench, most lenses are tuned to be sharpest between F2.8 and F5.6, approximately, but this is not a rule - many lenses are specifically designed to be their sharpest either wide open or very close to wide open. Macro lenses are tuned to be sharpest at smaller apertures and prioritize edge-to-edge sharpness over peak center sharpness. Many lenses are on the decline by the time they hit F5.6 - it simply depends on the individual lens design. Nothing about that is a mathematical truth, the sharpest aperture is simply what the lens engineers design it to be. It's also more complicated than that when you look at the whole frame - a lens that might be sharpest at the center at F2.8 might be sharpest across the whole frame at F8, albeit at a lower overall level, so you have to decide what compromise you want. Photography is a giant world of compromises or "pick 2 of the 3" type scenarios.
The second part of the equation is the sensor size and resolution (pixel density). The
M2P sensor is tiny, and at 20MP, has a very high pixel density (equivalent to a 147 MP full frame camera). The higher the pixel density, the earlier diffraction is going to start ruining your image quality. This is something that is objective and can be mathematically calculated. On the
M2P (Or any camera using a 20MP 1" sensor), diffraction will start to degrade the image after F4. On the
M2P, there isn't a big difference in image quality between F2.8 and F4, but by F5.6 it is noticeably softer, and by F8-F11 in my opinion diffraction has softened the image to the point it is barely usable outside of lower resolution applications like social media. The aperture matters a great deal if you care about image quality, because the high pixel density starts to cause you problems pretty early on with the 1" 20MP sensors. Everyone has their own subjective thresholds for what is "good enough", which is totally fine, but if we're discussing sharpness those are the facts.
