Low level over water flight

[Darrin]

I'm going to Bora Bora in a few weeks and envision using my MPs many intelligent modes as well as manually flying to record many of our experiences. I am thinking of shots where the MP would be flying a foot or two above the calm water for a fair distance and I'm wondering how risky this would be.

My fear is that there could be a problem maintaining altitude over water when only a few feet above the extremely clear water. Is this something I should worry about or would it be no different then maintaining altitude over land?


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[Andrew F]

I've done quite a bit over the ocean but stay 3 or more feet above the water. But that's as much for sneaker waves as it is for sonar concerns. Remember that there is a natural variation with your height so I wouldn't push it being too close It only takes one "glitch" to ruin your drone and your day. One thought, I bought the foam ball landing gear just in case I need to perform a water landing. You might consider that. I haven't used them yet, but here is what I bought: Amazon.com: DJI Mavic pro SNOW WATER MOD protector WHITE DRONE ON WATER OR SNOW landing: Camera & Photo

 

[BD0G]

You probably know to turn off downward vision sensors while doing this so the Mavic does not think you actually want to land on water. Consider a Polarized ND filter as well to cut some of the glare and orient it properly with relation to the lens.

 

[Chris J]

How do you know when your polarized filter is aligned "properly?" So far ive always mounted my Polar Pros with the ND number on the bottom and havent noticed any issues...

 

[Darrin]

Thanks guys, that gives me more confidence and direction. I won't go any lower than 3' above the water just in case and I have purchased the PolarPro six pack of filters so I should be good to go in that environment.

I'm in the Toronto area right now and have had my MP for a month but it's been so cloudy and cold lately practicing outside hasn't been often (logging approx 45 minutes of flight time) so reading this forum is all I have to educate me.


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[Starz]

How do you know when your polarized filter is aligned "properly?" So far ive always mounted my Polar Pros with the ND number on the bottom and havent noticed any issues...

Hold them up to look through them with something that is showing you some form of glare. Rotate the lense slowly and you will see the glare change its brightness. Mark the lense so you know where bottom is.(you want the glare to be as dim as you can get it)If you mark the top, it will be a little harder to see that because you probably have the mp laying upside down when installing the filter. There may be another way,but someone else would need to chime in.

 

[Starz]

Thanks guys, that gives me more confidence and direction. I won't go any lower than 3' above the water just in case and I have purchased the PolarPro six pack of filters so I should be good to go in that environment.

I'm in the Toronto area right now and have had my MP for a month but it's been so cloudy and cold lately practicing outside hasn't been often (logging approx 45 minutes of flight time) so reading this forum is all I have to educate me.


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hopefully no flying fish with empty stomachs. Going to Mexico at the end of the month and will be out over water myself watching some boats. Good luck!

 

[Andrew F]

You probably know to turn off downward vision sensors while doing this so the Mavic does not think you actually want to land on water. Consider a Polarized ND filter as well to cut some of the glare and orient it properly with relation to the lens.

I leave my vision sensors on. Not sure what you mean about landing. I won't tell it to land while over the water. At three feet or more, it doesn't start its landing procedure unless I hold the stick down. They say there is a negative issue near the edge of the water but I haven't experienced it. My Mavic is definitely afraid of waves however! Haha. It brakes when a big one crests in front of it (even though the wave is below it.)

 

[Gernby]

Hold them up to look through them with something that is showing you some form of glare. Rotate the lense slowly and you will see the glare change its brightness. Mark the lense so you know where bottom is.(you want the glare to be as dim as you can get it)If you mark the top, it will be a little harder to see that because you probably have the mp laying upside down when installing the filter. There may be another way,but someone else would need to chime in.

Ummm... why wouldn't the filters have a mark from the manufacturer, if they need to have a particular orientation?

 

[Starz]

The only thing I could attribute that to is something in the manufacturing process. Maybe too hard for them to keep all the alignments in correct position during that process.

 

[Chase R]

I read somewhere that the filter needs to be oriented before each flight due to changing angles of light. I just leave mine on.

Also flying somewhat low over water looks like you're almost touching it. I think you'll get the footage you want flying 6-10 feet above the water.

 

[saudio]

I read somewhere that the filter needs to be oriented before each flight due to changing angles of light. I just leave mine on.
.

that's what the support person at Polar Pro told me. You even need to reorient the filter as the light changes and as you point the camera in different directions. I, also, just put the **** thing on and leave it. If I wanted to deal with changing the filter each flight I'd buy the original ND filters that scrambled the gimbal.

 

[Egika]

Come on guys, read something on the internet how polarizing filters work..

 

[Andrew F]

I read somewhere that the filter needs to be oriented before each flight due to changing angles of light. I just leave mine on.

Also flying somewhat low over water looks like you're almost touching it. I think you'll get the footage you want flying 6-10 feet above the water.

That's absolutely true. I always feel like I am IN the water at 3 to 6 feet. Really an amazing experience. We are so lucky to get to be experiencing this remote viewing.

 

[Andrew F]

Come on guys, read something on the internet how polarizing filters work..

There are actually four (or more) types of polarizing filters, so it's difficult to know before you see the product. I wasn't able to ascertain from an employee what type of polarization was being used, but was told that during the manufacturing process the material would rotate randomly which is why there are no marks.

 

[Egika]

I can only repeat myself.
Get yourself some knowledge on polarizers. The effect varies with the position of the sun. You'll always need to adjust it and if you switch your gimbal from landscape to portrait it will change. As well as if you rotate your camera horizontally.

 

[halley]

The polarizing effect depends on the relative angle between the sun, the surface the glare is coming from, the direction of the camera, and the orientation of the polarizer. This is why they never mark one direction as "UP."

If you stood in the middle of a huge empty bowl, like a swimming pool or a smooth concrete skate park, and you held the polarizer up to your eye, you might notice less glare off SOME of the surfaces around you. If you twist the polarizer, SOME surfaces get their original glare back, and SOME different surfaces start getting less glare. If you walk around the environment and repeat the process, or you try the process at different times of day, which surfaces have more glare and which surfaces have less glare, will CHANGE. This goes for leaves on a tree, bright car paint jobs, windshields, all sorts of semi-glossy surfaces around you.

Before you fly with a polarized filter, you should try to stand facing the direction you'll shoot, look at the things you'll shoot, twist the polarizer to your eye, find a favorite position, put it on the drone camera, and fly. You can only hope that the altitude angle change doesn't throw all that out the window.

Polarized filters on drones will remain a mystery gamble, until you can interactively roll the filter orientation without rolling the camera.

 

[J-Dub]

I'm going to experiment over a calm lake someday... How about Tripod Mode? Figured in post I could always speed up the video.

 

[Egika]

Speeding up the video will also speed up all the movement in it. If all your filmed objects are stationary it's no problem. Water, waves, people, things that move with the wind will look awkward though.

 

[Starz]

So here's the solution. Just fly in one freaking direction, at one freaking time of day, at one freaking angle of view, with no freaking glare any where and your there!