Flying in Caves

videoarch · Mar 18, 2021

I would like to take an E2P into a cave and shoot some rock formations. We can carry a certain amount of light with us to light the cavern. With no GPS I need to calculate how much gear we need to carry. Does anyone know what level of EV this drone needs for indoor flight?

herein2021 · Mar 18, 2021

videoarch said:
I would like to take an E2P into a cave and shoot some rock formations. We can carry a certain amount of light with us to light the cavern. With no GPS I need to calculate how much gear we need to carry. Does anyone know what level of EV this drone needs for indoor flight?

I doubt you will be able to use OA at all in your scenario. The EVO II also needs a lot of light to take a decent image; I've found F2.8, 1/20s shutter, and ISO800 is the optimal low light settings. I don't know how bright your lights are or how much you will be able to light the cave but I am imagining a noisy underexposed mess.

I shot some caves in Va a few yrs back with a DSLR and I wasn't able to get good exposure without using F2.8, 5s shutter, and ISO3200 and that was with a full frame camera and plenty of lighting. If I were you, I'd do some above ground testing at night with the EVO and your lighting setup to see if it is even feasible from an exposure standpoint.

I think you may find a traditional camera with a tripod and a long exposure will work better.

videoarch · Mar 18, 2021

herein2021 said:
I doubt you will be able to use OA at all in your scenario. The EVO II also needs a lot of light to take a decent image; I've found F2.8, 1/20s shutter, and ISO800 is the optimal low light settings. I don't know how bright your lights are or how much you will be able to light the cave but I am imagining a noisy underexposed mess.

I shot some caves in Va a few yrs back with a DSLR and I wasn't able to get good exposure without using F2.8, 5s shutter, and ISO3200 and that was with a full frame camera and plenty of lighting. If I were you, I'd do some above ground testing at night with the EVO and your lighting setup to see if it is even feasible from an exposure standpoint.

I think you may find a traditional camera with a tripod and a long exposure will work better.

I appreciate your input. Thanks for taking the time to respond. Having worked on large budget ad shoots in this cave system I am comfortable with the technical aspects of imaging. I also have 10 years experience flying drones manually. I know this drone is not an Elios that's a given. What I was wondering is how much light do I need for the downward optical sensors to function. OA will be off. Bit of a difficult question for this kind of drone.

The Chinese companies that make many drones only test them in the commercial environments that sell their drones. Underground is not a big market. So there are few answers from them.

herein2021 · Mar 19, 2021

videoarch said:
I appreciate your input. Thanks for taking the time to respond. Having worked on large budget ad shoots in this cave system I am comfortable with the technical aspects of imaging. I also have 10 years experience flying drones manually. I know this drone is not an Elios that's a given. What I was wondering is how much light do I need for the downward optical sensors to function. OA will be off. Bit of a difficult question for this kind of drone.

The Chinese companies that make many drones only test them in the commercial environments that sell their drones. Underground is not a big market. So there are few answers from them.

That is a tough one to answer, I know it has the downward facing LED lights which help it land; I don't think there is any way to know ahead of time especially because it will also depend upon the reflectivity of the surface below the EVO II.

The EVO II also has the nasty habit of trying to land on anything you get too close to....I had it start trying to land on a light fixture 50' up in the air just because I was hovering too close to it so I'd keep that in mind as well. One of my feature requests is to provide a way to disable the auto landing feature but for now it will try to land on anything that gets within 5' below it.

videoarch · Mar 19, 2021

herein2021 said:
That is a tough one to answer, I know it has the downward facing LED lights which help it land; I don't think there is any way to know ahead of time especially because it will also depend upon the reflectivity of the surface below the EVO II.

The EVO II also has the nasty habit of trying to land on anything you get too close to....I had it start trying to land on a light fixture 50' up in the air just because I was hovering too close to it so I'd keep that in mind as well. One of my feature requests is to provide a way to disable the auto landing feature but for now it will try to land on anything that gets within 5' below it.

The downward vision sensors have three options in the app. Turning off landing assist but leaving on downward vision positioning should enable the drone to hover a bit with enough ambient light. How much is uncertain so prop guards will be necessary.

Hopefully the app will mature and give more manual flying control in the future. There does not appear to be a failsafe mode where the drone will hover in RTH mode which bothers me a bit. At least in the version I'm using. The Autel app definitely needs more control in RTH.

herein2021 · Mar 19, 2021

videoarch said:
The downward vision sensors have three options in the app. Turning off landing assist but leaving on downward vision positioning should enable the drone to hover a bit with enough ambient light. How much is uncertain so prop guards will be necessary.

Hopefully the app will mature and give more manual flying control in the future. There does not appear to be a failsafe mode where the drone will hover in RTH mode which bothers me a bit. At least in the version I'm using. The Autel app definitely needs more control in RTH.

Just keep in mind that you cannot disable auto landing despite how it may appear in the app. Disabling landing protection does not disable auto landing; I have tested it with everything disabled....when it hovers too close above something it still starts trying to land on it.

videoarch · Mar 19, 2021

herein2021 said:
Just keep in mind that you cannot disable auto landing despite how it may appear in the app. Disabling landing protection does not disable auto landing; I have tested it with everything disabled....when it hovers too close above something it still starts trying to land on it.

Yes I noticed that. Rather annoying. Since that feature has a GPS component to make it work I was hoping that with no GPS it might function correctly. A fantasy I'm sure.

herein2021 · Mar 19, 2021

videoarch said:
Yes I noticed that. Rather annoying. Since that feature has a GPS component to make it work I was hoping that with no GPS it might function correctly. A fantasy I'm sure.

That feature is based on the downward facing cameras.......even though the app tells you that you can disable them; the EVO II still uses them to detect and initiate the landing sequence and nothing truly disables it.

I tried everything including flying in pitch darkness and disabling the landing light......well that's not possible either, the landing light still comes on and helps it start the auto landing sequence no matter what you do; this is something I hope they change in the future. I need to land in some very tight spaces sometimes and the auto landing sequence makes that impossible.

In most situations its not a big deal, but I would imagine very undesirable in a cave environment.