Got the new Mavic Air up and running today for the first time.  Think I'll fly it a lot more than I do the Phantom due to size.

Anyway, I noticed when over a constant color  (like water), there is a noticabble semi-circle at the bottom of the video that has a different color and different level of detail.  My first thought is perhaps a finger print or something on the lens, but the detail actually looks better in that area than the rest (you can see the ripples in the water more clearly there than the rest of the shot - althogh that could just be from improved contrast int hat area).  I can't notice it over land, so I've got to go back out over some water to test it after wiping the lens, although it looked clear.

Since we are supposed to get rain the next 2 days, figured I would ask the forum if anyone had seen this before or had a better guess on what it might be.

Video was taken in full auto mode - 2.7k 30 FPS. No processing, this is as-is from the SD card.  Obviously, outside of this issue, I need to make some adjustments, but I'll worry about that later.




Thanks.

That looks like pixelation caused by a larger amount of light hitting that part of the sensor in the camera which will define that part of the image more. I take it you are not using ND filters? And what profile settings do you have for saturation, sharpness and contrast?

Other than the usual compression that is expected in this area with a lot of colour variations (banding) I don't see anything.
Maybe try different resolutions. (4K  / 1080 )

Looked great here.  Not seeing the problem at all.  Color variation is a difference in what the water is reflecting.  The brighter spots are reflecting a distant sky.

A CW Posted at 2018-4-23 10:07
That looks like pixelation caused by a larger amount of light hitting that part of the sensor in the camera which will define that part of the image more. I take it you are not using ND filters? And what profile settings do you have for saturation, sharpness and contrast?

Thanks for the quick reply. ND filters are on order, but have not arrived.  No filter and auto/defaults for everything (was really making sure it flew well before I worried about video).

Had the same issue flying both directions (can post the other if it is useful) so it would  not occur to me  that the light only hits that spot flying both north and south, although I guess reflection from the water could do it.

AG0N-Gary Posted at 2018-4-23 10:44
Looked great here.  Not seeing the problem at all.  Color variation is a difference in what the water is reflecting.  The brighter spots are reflecting a distant sky.

Thanks for the reply.  I'm good with the color variance across the water.  It's the semi-circle at the bottom (looks greener to my eyes) that never changes size, shape or position that seemed very un-natrual to me.  Maybe its just me then, and all is well.  

Thanks again.

EDIT:  On a re-watch my "semi-circle" does seem to contour to the land when it passes over, so I guess it probably is just the natural light -- I just hadn't noticed something like that previously witht he phantom, but different settings, different cameras, different light, and different days will do that.

JEZ2 Posted at 2018-4-23 10:50
Thanks for the quick reply. ND filters are on order, but have not arrived.  No filter and auto/defaults for everything (was really making sure it flew well before I worried about video).

Had the same issue flying both directions (can post the other if it is useful) so it would  not occur to me  that the light only hits that spot flying both north and south, although I guess reflection from the water could do it.

It's the reflection. You'll also notice small sun spots appear in your image when facing the sun - similar principle. Put on ND filters and polarised filters over large bodies of water and it will disappear from the image. The iris on the MA is quite open with a fixed aperture of f2.8 I believe so it will take a lot of light into the sensor. By using the ND filters you will also be able to significantly reduce the shutter speed and that will help smooth it out too.