Aerial Photography

© Brooke Clarke 2022




Background
DJI Mavic mini 2
    Description
    Operation
    Hints & Tips
    Photos
Patents
Related
References
Links

Background

This is related to my other web pages on photography and aircraft (see Related below).  A couple of decades ago I got a very small quadcopter (Wiki) that had a camera.  I played with in indoors since any wind would blow it into the forest.  It was a toy. 

I titled this page aerial photography because I also have an interest in all photography done from above the ground such as: photo reconnaissance aircraft,  spy aircraft and spy satellites.  There are straight forward optics equations that define the resolution of these systems.

This quadcopter is optimized for photography.  There are other styles of quadcopter such as the First Person View (Wiki) where the video coming back to the remote control pilot is to allow high speed maneuvering/racing.

DJI Mavic mini 2 (Wiki)

A few years ago a good friend got a DJI Mini 2 (DJI) Aerial Camera Bundle from Costco (Includes: Extra Battery, Mini Bag+ and 32GB MicroSD Card).  This is not as good as the Fly More DJI bundle, but probably more cost effective.  The thing that really impressed me was that the images he took looked like the camera was on a tripod.  I would call it a tripod in the sky.

The Costco bundle includes the DJI RC-N1 remote that couples to your cell phone.

DJI Mavic mini 2

Description

The overall weight is 249 g (less than the 250 g weight that requires more paperwork.
No obstacle avoidance, that comes with the mini 3 Pro.
Level 5 wind Resistance means it can fly in winds up to 19 - 24 MPH.  My experience with the toy quadcopter taught me that this is an important factor.
I got this at a discount, probably because the mini 3 Pro is now available.  It's a 249 gram quadcopter that has Tri-Directional (forward, backward, and downward) Obstacle Sensing.

Operation

A cell phone is used as an interface to the DJI Fly App. 
Power on the remote and DJI Fly app BEFORE connecting the USB cable!



YouTube: DJI MINI 2 | SECRET SETTINGS 1.4.0, 10:36 -
0:09 Tech-Drone Family -
0:20 Phone Charging - Settings\Control\Phone Charging: On
1:02 Camera Switch - use the camera in your phone to film the quadcopter, like taking off and/or landing.  This requires doing the takeoff and/or landing using the joy sticks (not the DJI Fly App which will not be accessible when the phone camera is in use).
2:34 1 Pilots Please? - "Added ability to control orientation of aircraft when flying forward during RTH." Rotating quadcopter gives great panning shots. Left stick rotate left or right.
3:57 Increase the Gimbal upward angle - Settings\Control\Allow Upward Gimbal Rotation
4:27 Data Geek - Settings\Camera\Video Subtitles (meta data): On - Requires video player turn on subtitles.
F/2.8, SS 728.01, ISO 100, EV 0, DZOOM 1.000, GPS (-30.0474,
53.9073, 28), D 2184.27m, H 701.20m, H.S 3.14m/s, V.S 0.20 m/s
5:11 Auto Sync Photos - Settings\Camera\Auto Sync HD Photos -
5:53 Quick(ish) Transfer - Holding down the light/button until it blinks blue allows quadcopter to join Wi-Fi network.  When done you must Switch to Flight Mode(upper right icon) to allow remote control.
6:44 Payload Off - activates when carrying extra weight.  Restricts to 30m hi & 50m distance.  Can be manually switched off.
7:46 Emergency Stop - quick press on Return to Home will very quickly pause & hover the quadcopter.
9:02 No Sticks No Problem - just move the controls with thumb on the threaded hole.  You actually get finer control this way.
9:44 Oops - some unique features that only the mini2 can do.

DJI mini 2 Hints & Tips

Micro SD Card

DJI Mini 2
                        MIcro SD card This was included with the Costco bundle.
SanDisk Extreme, 32 GB, V30, HC 1, U3, A1

(Wiki)
micro SDHC: FAT32, 2 - 32 GB
U3: 30, 60 or 90 MB/s;  V30= 30 MB/s
A1: Read: 1500 IOPS, Write: 500 IOPS
Also got the SIIG USB Type C 2-in-1 Card Reader mainly to get the 5Gbps speed associated with USB 3.0.  I remains to be seen if it will be noticeably faster than my existing USB-A (2.0) card reader.
My old reader transfers a 2.1 GB .mov file in 93 seconds.

Case to Hold 8 each Micro SD Cards & Spare cards


Propeller Strap

I have this on order since it did not come with the Costco bundle.  I feel much more comfortable using the strap that the props are protected.  See Fig 8, Fig 9 & Fig 10.

Batteries

Just a thought now, but in an emergency if live broadcasting video, like a wild fire, how many batteries would be needed to continuous coverage?
With one battery in mini2 and 3 fully charged batteries in the charger you would have about 4 * 30 minutes or 2 hours.
The number of batteries will be determined by the charge time of the charger for one battery and the capacity of the remote battery which may need an external battery bank.

Is there a limit how long a mini 2 can fly?  Some products shut down if too hot.

3 Battery Intelligent Charger with LCD (not DJI brand)

Polarizing Filter

I have a polarizing filter for some of my Nikon lenses and understand how they cut reflections.  But the video demonstrates that they have a positive effect on color balance.
YouTube: DJI MINI 2 FREEWELL Polarizer Filter vs NO FILTER: BEST Side by Side Comparison on YOUTUBE! 4K VIDEO -

DJI Fly App

Looking for the DJI Fly app in the Android Play store comes up with many hits, but none of them is the correct DJI version.  To find it go here on your phone and select the Apple or Android version.
https://www.dji.com/downloads/djiapp/dji-fly -or- https://www.dji.com/mini-2/downloads
During the install you will need to agree to give DJI access to pretty much everything.

Litchi Tracking (LitchiFly)

This is a third party app that makes use of the DJI Software Developers Kit (SDK) that does tracking.  But since there's no obstacle avoidance on the mini 2 it's up to the operator to avoid hitting something.  The app includes other features like FPV, way points, orbit, VR goggles, focus (select target, can be a separate Android device), Panorama (H, V or Spherical), Track.

It works by tracking your mobile phone that is running their app.  That also means you need to also have your remote on your person.
This single app works with most of the DJI quadcopters.
It appears to require a medium learning curve to get working.

LG G6 "Moisture in USB port" error

The first time I saw this error was in relation to the DJI mini 2 remote.  My phone has never been in water.

The following YouTube starts with the phone on it's home page.
YouTube:


DJI mini 2 Check USB Port. Charging Blocked due to moisture No. 2

I was able to install the app on my phone and go through the initial startup process and make a couple of test flights, but did not get as far as turning on the camera.  Then trying to make my third test flight this error has persisted and I can no longer open the Fly App.

This happens to the point that it's almost impossible to use the mini 2. 

Troubleshooting

A possible solution is to power down the phone and reboot it.  I'll try that.  Another possible reason is a USB cable with leakage resistance that the phone sees as moisture.  That was my first thought, but I found a posting suggesting the re-boot which is easier to try as a first step.  That did not work.

Connecting the short USB-C to USB-C cable to only the LG G6 VS988 phone does not bring up the error. (Tried this while the Use USB Connection was in Power Supply mode).  But nothing happened.  Probably because until the phone sees a DC load it does not do the moisture check.

Check USB Port. Charging Blocked due to moisture.

Next try wiping the Cache partition (Wiki How):
Settings \ Storage \ Internal Storage \ Free up space - delete Temp files & data: select items & delete Download folder: select items & delete; idle apps: select all & delete.
Power down & reboot.
Plugging in remote USB cable with remote powered down, no problems.
Powering up remote: Charging Blocked due to moisture.

In the LG G6 phone (Android ver 9): Use USB Connection for: was set to Power Supply - Charge the connected device.  Changed to Charging - Just charge this phone. ALWAYS.
Does not help.  As soon as the DJI remote is connected and powered on it must be asking the phone to charge it since when I look again at the Use USB Connection it has gone back to Power Supply.

DJI English tech support: 1 (818) 235-0789 Mon-Sun 6:00 - 18:00 (PST) was no help. A supervisor is supposed to call me back.  Called back the next day, not a known problem, engineers will look into it.

There may be a way to change some setting in the DJI Fly App, but I can not get into the app because of this error.  Maybe there's a way to reset the app?

Another possible solution would be to use the new DJI RC remote that does not require an external cell phone, BUT it's manual only mentioned two products: DJI Mini 3 Pro O3 & DJI Mavic 3: O3+.

My LG G6 VS988 is not on the recommended list of Android devices.  That list is very short.

Android Ver 9 USB settings

Settings \ System\ About Phone \ Software info \ Build Number (tap this 7 times) to turn on Developer mode.
now
Settings \ System \ Developer Options \ Select USB Configuration: A data cable must be connected between the phone and a computer, then the Use USB connection screen shows up.
I set it to Charging (just charge this phone) and ALWAYS.

Checking DJI RC-N1

Still get the Check USB port error when connected to the DJI RC-N1 remote.
Going back to the Use USB connection screen by connecting to a computer shows the option set at Charging NOT Power Supply.
I think that means there's a problem in the DJI RC-N1 remote or it's settings.

Normal phone charging

I normally charge this phone using a USB-C cable.  There has never been an error message about moisture.  (I think using wireless charging coupled with being in an area where there's a very weak cell signal has lead to exploding the battery in my previous three cell phones.)

Solution

Power on the remote and DJI Fly app BEFORE connecting the USB cable!

DJI Assistant 2 (Consumer Drones Series)

WIN 7 Version is 2.1.10 9 Aug 2022.
The installation failed.  DJI WM160 USB Device loaded OK, but RNDIS and CDC Serial failed.

If needed:

So far I can move the video from the micro SD card to my WIN7 desktop computer and watch the silent movie on the computer.
BUT . . . so far have not found a way to see the movie on my Sony Bravia big screen TV.

Casting & Mirroring

Google Chrome can cast the computer screen, but that format is not compatible with the Roku device.  I am able to display my Android phone screen on the Sony via Roku.
Roku: How to cast apps like YouTube or Netflix from your phone to a TV - no help since it depends on an app
How to screen mirror your Android™ or Windows® phone to your Roku® streaming device - no help since it only works from a phone
Connecting Desktop with Roku Ultra - by means of HDMI, not LAN
Can no longer chromecast to streaming stick+ - 2) Roku does not support GoogleCast (aka ChromeCast - casting & mirroring) - True, when I try "
Cast tab
Roku Ultra
Available for specific sites
the above is grayed out and can not be clicked
Got some SanDisk Cruzer Blade USB2 thumb drives.  They come formatted as FAT32 (Wiki) , so my WIN7 computer did not see them.
After formatting as NTFS (Wiki) and assigning a new drive letter that did not conflict with existing drives I can write the MP4 video file.
But . . . my Sony Bravia TV, even though it will accept USB still and video files, does not recognize the NTFS stick.

Still Photo Size

Can be set to 48 MP.

In DJI App be in Photo mode (not video mode).
Click on J+RAW and for me: J+RAW rather than jpg only.
Size options: 4:3 or 16:9.  4:3 uses more of the camera's pixels.
In Photo mode (not video) tapping the lower right [auto] icon will bring up the [pro] manual settings menu.
Auto Exposure Bracketing (AEB) takes 3 images that could then be stacked in Photoshop for increased dynamic range.
ISO @ 100 for best results.
Stills, highest shutter speed available.
Photo\Pano\Wide-angle:  this takes an array of 9 images each in 4:3 aspect ratio for a huge image.

Photos

DJI Mini 2

Fig 1 Box as received: 11-3/4 x 7-1/2 x 6-1/4 weight 3# 4oz
There is also an UN 3481 battery label
Delivered by UPS ground.
There was a crushed air pillow in the box.
DJI Mini 2
Fig 2 Item: 1162016
UPC: 190021037441
DJI Mini 2
                      Costco Bundle

Fig 3
DJI Mini 2
                      Costco Bundle
Fig 4
DJI Mini 2
                      Costco Bundle
Fig 5 Spares Box
DJI Mini 2
                      Costco Bundle
Fig 6 Remove before flight
DJI Mini 2
                      Costco Bundle
Fig 7 Charging using standard USB -C cables
DJI Mini 2
                      Costco Bundle
Fig 8 DJI mini 2 Propeller Strap
DJI Mini 2
                      Propeller Strap
Fig 9
DJI Mini 2
                      Propeller Strap
Fig 10
1. Unfold the front arms forwards
2. Unfold the rear arms downwards.
DJI Mini 2
                      Propeller Strap
Fig 11 Micro SD Card
DJI Mini 2
                      MIcro SD card


Patents

Almost three thousand DJI US patents.
20220197309 Systems and methods for operating unmanned aerial vehicles, DJI, 2022-06-23, - changing the length of rotor arms to balance a change in the center of gravity (why? dropping munitions, package delivery, optional cameras?)

20160313742 Methods for launching and landing an unmanned aerial vehicle, Ming-Yu Wang, DJI, App: 2013-12-13, Pub: 2017-07-04, - Phantom (Wiki, DJI)? - under slung GoPro type camera
D768539 Aerial vehicle, Seung Heon Lee, GoPro, App: 2015-08-04, Pub: 2016-10-11, - folding arm quadcopter
20190185169 Unmanned aerial vehicle, Bogao XU, Zhenzhou LAI, Lei Wang, DJI, Priority: 2016-08-23, Pub: 2019-06-20, - Mavic?
D814970 Aerial vehicle, Shaojie Chen, Yumian Deng, DJI, App: 2016-02-22, Pub: 2018-04-10, - Mavic?
D868177 Controller, Yiwei Chen, DJI, App: 2018-07-20, Pub: 2019-11-26, - DJI RC?
20190375510 Unmanned aerial vehicle, Li Qiu, Mingxi Wang, DJI, Priority: 2017-02-24, Pub: 2019-12-12, - Phantom?
20200001990 Automatically and releasably coupling UAV propellers to propulsion motors, and associated systems and methods, Bin Jiang, Guannan Ren, DJI, Priority: 2017-03-15, Pub: 2020-01-02, -
20200023995 Unmanned aerial vehicle, Liang Song, Hongyun MA, Yazhen WEI, DJI, Priority: 2016-12-26, Pub: 2020-01-23, - optical object avoidance
20200148350 Unmanned aircraft, Guisheng NONG, Lei Zhang, Yin Tang, DJI, Priority: 2017-04-26, Pub: 2020-05-14, - Spark
D861573 Aerial vehicle, Baichuan He, Yumian Deng, Wenbo Li, DJI, App: 2018-01-19, Pub: 2019-10-01, - mini or mini2 ?
D869375 Aerial vehicle, Min Kim, Siyoon Kim, Guisheng NONG, Lei Zhang, Peng Bin, Tianhang MA, DJI, App: 2017-04-13, Pub: 2019-12-10, - Spark fixed motor arms, the mini has folding arms
D874532 Camera with gimbal, Yiwei Chen, DJI, App: 2018-06-26, Pub: 2020-02-04, - mini camera?
D905596 Aerial vehicle, Shaojie Chen, Yumian Deng, DJI, Priority: 2016-02-22, Pub: 2020-12-22, - one of the Mavic or mini series? 130 citations, maybe with optical avoidance?
D918087 Aerial vehicle, Baichuan He, Yiwei Chen, Shaojie Chen, DJI, App: 2019-07-12, Pub: 2021-05-04, - Design for the mini 2, 16 Figures.
20210341610 Ranging device, Shuai Dong, Xiaoping Hong, Huai Huang, DJI, Priority: 2019-01-07, Pub: 2021-11-04, - Zenmuse L1 - LIDAR also see: 20210336566, 20210333401, 20210333375, 20210333369, 20210333362, 20210333393, 20210335016, 20210335015, 20210335019, +many more
D931386 Controller, Min Kim, DJI, Priority: 2020-03-10, Pub: 2021-09-21, - RC-N1 remote control
D944665 Gimbal with detection device, Lin Li, DJI, App: 2020-06-30, Pub: 2022-03-01, - Zenmuse L1 - YouTube:

Related

Aircraft
DigitalPhotography101 Digital Photography 101: The Basics
Digital Photography 201 Stacking Images
Digital Photography 202: Close-Up, Macro & Micro
Digital Photography 203: Color Management
Digital Photography 204: Studio Flash
Digital Photography 205: Astrophotography
Digital Photography 206 Micro Photography
Electro Optical Gadgets
Optics

References

YouTube: DJI

Links

PRC68, Alphanumeric Index of Web pages, Contact, Products for Sale
Page Created 2022 Aug 2