Mavic Air - Lens distortion (creating awareness!)

[Kreigor-Celtic Warrier]

I'm not that picky abt my vids. In fact, I never shoot in 4K,
'cause I got nada monitors that are 4K..
I feel fortunate that the bird comes back to me at all.. And that I've been lucky in not losing it or crashing yet..

I know, I know, there are only 2 kinds of Quad pilots: those who have crashed and those who will eventually CRASH.

I do this for fun only, and when it's not fun, I'll put the bird away 'til the next time I get the urge to "FLY FLY UP AND AWAY INTO THE WILD BLUE YONDER>>>"

'Fly Safe' and always have fun..............

 

[irpnetgb]

Okay, maybe I'm missing something here, isn't this just a characteristic of the wide angle lens on any camera (hence why DJI say it is not a problem)?

 

[jettoblack]

Okay, maybe I'm missing something here, isn't this just a characteristic of the wide angle lens on any camera (hence why DJI say it is not a problem)?

Not really. All lenses have some distortion, and wide angle lenses tend to have more, because it is harder to correct. Better lenses use more elements to correct distortion. The downside of adding more elements to correct distortion is increasing the size, weight, and cost of the lens. Simple barrel or pincushion distortion aren't too noticeable and are easy to correct in software. Fisheye distortion (like on GoPro cameras and ultrawide lenses) is very noticeable but also has a certain "natural" aesthetic look to it, and people are used to seeing it, so it isn't too bad either. And fisheye is also easy to correct in software.

The problem with the MA lens is that it has strong complex lens distortion (pincushion towards the center, barrel towards the edges) which causes some extremely strange and noticeable distortion effects, especially when panning. To me, this looks way worse than simple barrel or fisheye distortion because it doesn't look natural at all. It's the kind of thing that once you see it, you can't unsee it. If you need a before/after comparison I can post one.

Some camera systems use internal software correction to correct the distortion so you don't notice it. The Mavic Air corrects it in JPEG stills, but not in RAW stills or in videos. The Mavic 2 Pro corrects the distortion in stills and videos in 8-bit mode, but not in video in 10-bit mode. The M2P distortion in 10-bit video is a relatively mild barrel distortion which is much less offensive and easier to correct than the complex lens distortion on the MA.

 

[irpnetgb]

Not really. All lenses have some distortion, and wide angle lenses tend to have more, because it is harder to correct. Better lenses use more elements to correct distortion. The downside of adding more elements to correct distortion is increasing the size, weight, and cost of the lens. Simple barrel or pincushion distortion aren't too noticeable and are easy to correct in software. Fisheye distortion (like on GoPro cameras and ultrawide lenses) is very noticeable but also has a certain "natural" aesthetic look to it, and people are used to seeing it, so it isn't too bad either. And fisheye is also easy to correct in software.

The problem with the MA lens is that it has strong complex lens distortion (pincushion towards the center, barrel towards the edges) which causes some extremely strange and noticeable distortion effects, especially when panning. To me, this looks way worse than simple barrel or fisheye distortion because it doesn't look natural at all. It's the kind of thing that once you see it, you can't unsee it. If you need a before/after comparison I can post one.

Some camera systems use internal software correction to correct the distortion so you don't notice it. The Mavic Air corrects it in JPEG stills, but not in RAW stills or in videos. The Mavic 2 Pro corrects the distortion in stills and videos in 8-bit mode, but not in video in 10-bit mode. The M2P distortion in 10-bit video is a relatively mild barrel distortion which is much less offensive and easier to correct than the complex lens distortion on the MA.

Ah, thanks! Well explained. I can't say I've ever noticed it on my video (my eyes aren't what they once were), but as you mention, I have noticed it in my stills.

 

[VFXxx]

Are you able to send me the template aswell ? I think that DJI must feel embarassed that one of us made a lens fix, that they couldn't do. Even a cheaper smartphone has less distortions than the mavic air.
Thank you very much: [email protected] !

Could you send me the template please? That would be really handy to have, thanks! My address: [email protected]

Hi Jonh and Vincent, please check e-mail.

 

[default_tune]

I would love to get the template too! I have been searching for the solution forever.
[email protected]

 

[KevinMA]

I have been doing some testing and its more prevalent when turning the craft when the horizon is high in the video.... its less obvious when the horizon is half way or lower than half way in the video...

And I have looked at quite a few video on youtube by Mavic Air testers producing their "first flight" videos... and you can see this in a lot of them, and I think they haven't really noticed it yet.

I have been in touch with DJI support and shown them test videos and its not really good when they come back and say "I have provided all your videos to our R&D team and they checked it for you, according to the R&D team, the videos that you provided are normal, there is no problem of your drone, so please don't worry."

I have asked them if they are producing a firmware fix and to be honest they haven't even acknowledged that I asked that question.

Their support is a joke, they’re only willing to talk about things they want to talk about

 

[VFXxx]

I would love to get the template too! I have been searching for the solution forever.
[email protected]

Hey Alex check your inbox

 

[KevinMA]

Hey Alex check your inbox

Can I get it also

[email protected]

 

[Amarand]

A lot of great replies here!

As a guy who’s been into photography since the 80’s, I’ve had to deal with lens distortion because cost has always been a factor. Good glass isn’t cheap, and a $1000 SUAV has probably $10 (cost) in the lens. I own lenses for my DSLR cameras that cost much more than even the Mavic 2 Pro.

Having said that, this is why I always shoot RAW when I can. Lightroom (and Adobe Camera Raw) will see the embedded lens correction data, and automatically apply it to each image. Fixes almost all of the abnormalities, leaving you with a much cleaner image.

I know there are benefits to shooting JPEG, and for sharing images on social media, they’re probably just fine. But all JPEG edits are lossy, so even that first save-out on-drone creates artifacts in the image. Adjust the image in Photoshop, you’ve added another layer of noise. And so on.

RAW is non-destructive editing. So, I’m a Big Fan of shooting RAW on the Mavic Air for the simple fact that I know my images won’t degrade each time I save out a new set of edits.

Also, white balance is “baked into” JPEG files, so removing color cast is a lot more challenging with JPEG than RAW, which is completely non-destructive as well.

Anyway...hope that helped a bit?

 

[FrankGQ]

Hi @VFXxx Can I have it too? [email protected] ??

 

[Alex Santor]

hi @VFXxx
Could you send me the template please? I will be very grateful
My address: [email protected]

 

[CamFlyerCH]

Hello
I found that for Pictures the Application RawTherapee has built in lens correction templates !



But is is not a very good match (Sorry, my source picture has a slight tilt)

Original


Corrected

 

[CamFlyerCH]

I wan't to correct my video footage in Magix Vegas. I recorded a test pattern in 4k 30FPS and 2.7k 60FPS. Not perfect , but at least I do not notice the Problem anymore.

Original 2.7k


Corrected


Here my settings:


I hope that helps others to get better looking videos. In my case I filmed an office building and the warped lines where clearly visible !
(Still not perfect with the correction)

 

[mavictweak]

Got the same issue with my brand new Mavic Air.
Doing shot 3d tracking is nearly impossible with that sort of distortions,

so i made myself a bootleg After Effects template to correct Lens Distortion for MA's 4k footages.

Will share here if this is useful.

View attachment 55118

Can you share with me as well? [email protected]

 

[CamFlyerCH]

I tried to analyze the (raw) photos with Hugin and create my own lens profile.
Guides:
Creating lens distorsion models with Hugin's lens calibrator | Libre Graphics World
Old Hugin version, with naration
New Hugin version, without naration

I created the MavicAir.ini that can be used by Hugin.

The found values are:
a=0.0166648
b=-0.112041
c=0.153356

These work also for Vegas if you have pictures in your video project. (see previous post in this thread)

Then I wanted to use RawTherapee to work on RAW (.DMG) files or also JPEG files. For lens corrections it uses lensfun library. The Mavic Air cam is already in the file "C:\Program Files\RawTherapee\5.8\share\lensfun\actioncams.xml" . Search for this entry:

<lens>
<maker>DJI</maker>
<model>FC2103 &amp; compatibles</model>

Change this line to (the in my opinion better values):
<distortion model="ptlens" focal="4.5" a="0.0166648" b="-0.112041" c="0.153356"/>

In RawTherapee also the amount of distortion correction applied must by changed 0.030 to not overdue the correction. I put this in a processing profile (to apply partially) = Mavic_Air_Lens.pp3 (place it in %USERPROFILE%\AppData\Local\RawTherapee\profiles)
I did not get lucky with color grading RAW images of the Mavic Air using RawTherapee. Does anyone have a good profile for that ?

 

[treben]

I noticed this as well. DxO added support for the Mavic Air's raw files in photolab and that has helped me with the issue, but it's nice to see users creating custom templates for this issue.