Horizon curvature

[Pchantler]

I recall seeing something on this topic a few months back. I had to return my original M2P to DJI and it was eventually replaced. I never experienced this with the first one but am experiencing this regularly now with the replacement. When I take a photo from altitude where the horizon is visible, there is a noticeable curvature which looks like the natural curvature of the earth but impossible at 40-50 meters altitude. I do most of my photography in AEB mode and use various Polar Pro ND filters. I don’t think either of those are the cause and before someone asks, I haven’t tried eliminating the filter first. I’m sure there is an explanation, I just can’t figure it out. Any one that has experienced this and knows the solution, please let me know.

Thanks

 

[Meta4]

When I take a photo from altitude where the horizon is visible, there is a noticeable curvature which looks like the natural curvature of the earth but impossible at 40-50 meters altitude.
I’m sure there is an explanation, I just can’t figure it out. Any one that has experienced this and knows the solution, please let me know.

The logical place to start is:
Are you shooting raw and what software are you using that's showing curvature?
Like most wideangle lenses the lens of your drone camera has barrel distortion and many graphics programs automatically correct that.

 

[Pchantler]

The logical place to start is:
Are you shooting raw and what software are you using that's showing curvature?
Like most wideangle lenses the lens of your drone camera has barrel distortion and many graphics programs automatically correct that.

Yes shooting in raw. When I shoot AEB I use photomatix to process the HDR then photoshop to finish the processing. Never thought of the HDR software being the culprit but it’s a place to start. Will take some of the single photos and run them directly through photoshop and see if there is an improvement

 

[DebianDog]

I use Lightroom but somewhere in Photoshop you should see

 

[brett8883]

I use Lightroom but somewhere in Photoshop you should see
View attachment 69753

Gotta love DNGs!

 

[CanadaDrone]

Yes shooting in raw. When I shoot AEB I use photomatix to process the HDR then photoshop to finish the processing. Never thought of the HDR software being the culprit but it’s a place to start. Will take some of the single photos and run them directly through photoshop and see if there is an improvement

The drone does not correct for lens distortion in RAW still images or in DLog-M 10bit H265 video (FOV mode is worse than HQ for this). It's not supposed to.

RAW image data is just that - the RAW data off the sensor with no alteration. No corrections have been made as the whole point of RAW is that you get to do everything yourself manually in the post processing program of your choice, with the most malleable possible file.

Anyways you can correct the M2P barrel distortion in one click in just about any RAW editor - nothing to worry about and everything is behaving as it should.

 

[Paul2660]

With raw/dng, the more you point the gimbal up, the more you will see distortion. You should not see a natural downward curve, like curvature of the earth, but an upward curve towards the edges. If you have the gimbal pretty close to even on the horizon, it will be very even no curve.

As pointed out, most raw converts will have a lens correction for this. Adobe Lightroom, or ACR now have good corrections for the MP2 and with Version 12.x of Capture One, it also does a great job. If you take the raw files into a converter like Photomatrix, will will not correct for distortion as it has no understanding of the optics. If you want to use Photomatrix, I would recommend using it as a plug-in from Bridge or Lightroom, that way the correction will be applied to the raw before you send it. You can also use the HDR tool in Lightroom or Bridge to do the same type conversion Photomatrix can do.

I have attached 2 screen shots, one shows a before and after of a MP2 in Capture One, and the other is a straight raw view in Fast Raw Viewer of a MP2, showing the natural distortion created by looking up. Same issue occurs in the raw files from Phantom cameras also.

Paul C