A Flying Camera – DJI Mavic Pro

A Flying Camera – DJI Mavic Pro

If you are a photographer or videographer and you are interested in the Mavic Pro drone primarily as a flying camera, then this article is for you. This is a run-down of camera controls and options, without discussing flight controls.
Documentation included with the Mavic Pro is minimal and help for the DJI Go app is non-existent.

First of all, let’s point out the obvious. The Mavic Pro has unmatched portability; it folds to a size that can fit in a large coat pocket. The gimbal that stabilizes the camera is probably the smallest in the world.

This drone can be flown using using the hand-held controller alone, or in conjunction wtih a smart-phone and the DJI Go app. You do need the Go app for access to numerous configurable options, but after configuring what you need, it is possible to fly with just the controller and no app. During flight, the Go app gives you a live video feed and camera exposure information, but you may not need to interact with the app except maybe to set the focus.

Not all available features shown here.  These are just some features I wish to point out.

The Remote Controller

The hand-held controller includes quite a few camera controls, independent of any smartphone app.

  • Photo trigger (shutter button)
  • Start/stop video recording
  • Camera tilt
  • Exposure compensation
  • Custom button left (e.g. center focus)
  • Custom button right (e.g. AE lock)
  • 5D button – up, down, left, right each has a different meaning that is configurable.
    (For example, zoom in/out. It is a 2x digital zoom; there is no optical zoom.)

DJI GO app

The app shows real-time video and provides in-flight camera exposure information.

  • Real-time image view
  • Exposure histogram
  • Current exposure compensation setting (1/3 ev increments)
  • Over-exposure zebra stripes during video recording
  • Camera: ISO, shutter speed, white balance, remaining SD card number of photos
  • Video: resolution, FPS, remaining SD card recording time

The app provides extensive camera configuration options.

  • auto/manual exposure
  • ISO (100 to 6400)
  • shutter (up to 1/8000)
  • AE lock
  • touch screen for AF spot
  • touch screen for exposure spot

video menu ___

  • NTSC or PAL
  • size&fps (e.g. 720p @ 120fps, 4K @24fps)
  • White balance (auto, sun, cloud, custom, etc)
  • Style (brightness, contrast, tint)
  • Color (none, D-cinelike, D-log, Art, Vivid, etc)

photo menu ___

  • Aspect ratio (4:3, 16:9)
  • Image format (jpeg, raw, jpeg+raw)
  • Photo drive (single shot, AEB-3, AEB-5, HDR, interval)
  • White balance (auto, sun, cloud, custom, etc)
  • Style (sharpness, contrast, saturation)

options menu ___

  • show real-time histogram
  • orientation (portrait/landscape)
  • lock gimbal when capture
  • over exposure warning
  • anti-flicker (50Hz, 60Hz, auto)
  • format SD card

The app alerts you if a firmware update is available. The update can be applied with a simple touch; the download comes via your wi-fi, through the phone, down to the drone. The time to complete the upgrade was more than ten minutes and consumed about 18% of the drone battery charge.

Bearskin Neck
Bearskin Neck
Compare JPEG to RAW
Compare JPEG to RAW

Photo Quality

For photos, you can shoot RAW, JPEG, or RAW+JPEG. Of course, I recommend either RAW or RAW+JPEG.

I shot the photo above (Bearskin Neck, Rockport MA) recently with the Mavic Pro set to record both JPEG and RAW.  The second photo is a 200% crop from the center, comparing the original JPEG to the RAW file processed as I normally would in Adobe Lightroom.  Overall, the JPEG is good.  I think it is a bit green, looking at the short stone wall.  Signs on the buildings are not legible in either case, but the JPEG is slightly worse than RAW.

With only a half dozen flights thus far, I have observed a couple specific image quality problems.  For still photos, the very small image sensor is no match for a larger DSLR or MFT camera.  I have read that the image sensor is Sony Exmore (wikipedia.org/wiki/Exmor), but I cannot confirm that. The maximum resolution is a respectable 12 megapixels, in 4×3 aspect ratio (4000×3000). You can choose to capture 16×9 ratio, but that is a crop down to 9 megapixels (I personally tested that just now; that’s real, not a guess.).

Photos can exhibit some amount of digital image noise at just about any ISO. Images shot during the low-light of dusk, around ISO 1600, exhibit a high amount of chroma noise.  Samples are shown here below.  For stills, Adobe Lightroom has the best noise reduction I know. While the JPEG processing in the Mavic does a reasonably good job of smoothing large areas, there is loss of detail inside the bridge.  The Topaz Denoise plugin for Adobe is similar.  Processing via Lighroom’s built-in noise reduction allows better control and retains better detail inside the bridge.

Coping with low light

Video Quality

In good light, the video quality is probably on par with a GoPro Hero 3 or 4.  Moire problems may occur when scenery includes detailed patterns, but I have not tested this with different capture resolutions.  As with still photos, low light and high ISO exhibits a high amount of chroma noise.   A product called Neat Video can do a good job of mitigating noise.

The video clip of the snowy mill (at the beginning of this article) was captured at 1080 without a problem.  However, on a separate shoot, I did see a problem.   Several people contributing to on-line forums have reported that 1080 does have problems, including a “pastel effect” which seems an apt description of the problem I saw. People experiencing problems at 1080 also report that the problem does not occur at higher 2.7K or 4K resolution. I have switched to shooting 2.7K and subsequently downsample to 1080 in post processing. However, the higher resolution does not support a frame rate faster than 30 fps; and downsampling does require additional compute time.

For video, I’ve been shooting the “None” color profile, modified with sharpness set to -1. Some pros are recommending two of the color profiles, DLOG (very flat) and ART (not as flat). Alternatively, some people have suggested color profile D-Cinelike and then customized to -2, -1, -1 (sharpness, contrast, saturation). All those suggestions create an intentionally flat result that necessitates some post-processing.

A clear plastic dome can optionally be used to protect the camera. Very first time I captured video with the Mavic Pro, I could see glare due to the plastic dome. Since then, I never fly with the dome attached. Potentially, I might use it if there some risk of water or dust in the air, for example, flying near a waterfall.

 

Pre-flight

Each time you fly, here’s the basic pre-flight steps:

1) Unfold the propeller arms and propellers
(Obviously, attach any propellers that you detached for transport/storage.)

2) Remove the camera gimbal clip

3) Optionally, connect your smart-phone to the hand-held controller

4) Turn on the controller and start the DJI Go app

5) Turn the antennae upwards, which is typically a 45-degree angle

6) Turn on the drone

7) To connect your phone with the drone, touch the “Camera” button on the DJI Go app

8) Check the aircraft status information, including available battery charge

9) If this is a different location than previous flight, calibrate the compass

10) Obviously, check your environment for obstacles or hazzards.
Make sure you are not in restricted airspace.

 

DJI includes a plastic clip to secure the camera gimbal when not in use. Always remove this clip BEFORE turning on the drone. If you fail to do so, the app warns of gimbal overload.

Initially, the Go app will display the “Aircraft Status”. Tap the “X” to close this display.

  • Overall status … Latest Firmware
  • IME … normal
  • Compass … normal
  • Motor ESC status … normal
  • Radio Channel Quality … good
  • Flight Mode
  • Remote Controller mode
  • Aircraft battery
  • Remote Controller battery
  • Remaining SD card capacity

 

The Next Phantom Quadcopter Drone – Phantom 3

Last October, I listed Drones for Under $2000.  A week later, DJI announced a new quadcopter drone, Inspire 1, which was notable, but far above the $2000 price point. This week, DJI announced the third incarnation of it’s original Phantom, which now incorporates some features from Inspire but retains the more affordable price tag of the Phantom line.  Here are the broad brush strokes.

Phantom 3 (DJI press release photo)

Phantom 3

  • Improved camera system supports video and stills. Phantom 3 “pro” supports 4K video resolution.
  • 3-axis gimbal, similar to Phanom 2 Vision
  • The new gimbal seems to pan, unlike its predecessor on the Phantom 2 Vision+
  • Digital video downlink sends live video feed to your mobile device on the ground (up to 720p)
  • Downward-facing visual and ultrasonic sensors allow position hold without GPS (indoors), like the Inspire 1
  • Improvements in motors and motor control provide better stability and longer battery life.

Phantom 3 vs Inspire 1

  • Inspire 1 is larger than Phantom and can fly faster
  • Inspire 1 allows unobstructed 360 degree camera rotation – retracting landing struts will not obstruct the view.
  • Inspire 1 supports dual pilot operation.
  • Phantom is theoretically much more durable than Inspire
  • Phantom costs far less than Inspire
  • Phantom provides a slightly longer flight time.

Not to be left behind, 3D Robotics will soon release their new quadcopter, currently known as SOLO.

Drones for Aerial Photography, under $2000

Drones for Aerial Photography, under $2000

Kevin flying a DJI Phantom
Kevin flying a DJI Phantom

The term “drone” is commonly used in pop media, more common than alternative terminology UAS (unmanned aircraft system) or UAV (unmanned aerial vehicle).   To my mind, a drone implies an automated military device – I prefer the term quadcopter.

As far as you or I are concerned, we serve as the remote pilots while standing on terra firma.  We operate a radio transmitter while the copter is equipped with a matching radio receiver.  Different radio systems are available and they are not all compatible.  For example, some communicate via a 2.4 GHz radio frequency, while others utilize a 5.8 GHz.  The differences are not limited to radio frequency alone.

Anything that is labeled as Ready-To-Fly (RTF) will include a radio transmitter that is compatible with the drone.  If the product is not advertised as RTF, it may not include a transmitter, which is preferable for anyone who intends to re-use an existing transmitter they already have.

  • 3D Robotics Iris+  … $750
  • 3D Robotics RTF X8 … $1,350
  • Blade 350 QX      – $470
  • DJI Phantom I … $400
  • DJI Phantom II Vison+ … $1,300
  • Gaui … 330X … $400
  • Gaui … 500X … $1,150
  • Gaui … 540H  / hexcopter (6 rotors) …  $600 does not include transmitter
  • Parrot   AR drone … $300
  • Quantum Nova … $320
  • Quantum Venture … $400
  • TurboAce Matrix … $900
  • HUBSAN  X4  H107C-HD
  • SteadiDrone QU4D … $1700
  • Walkera QR X350 … $400
  • Walkera QR 800 … $1,700
  • Walkera TALI h500  / hexcopter (6 rotors) … $1900

For aerial photography purposes, you need a stable device that is easy to control – consider electric copters only.  Gas-powered machines are loud, extremely fast, and potentially very dangerous.

The rotational force of a single-rotor will tend to rotate the entire machine; this is why traditional helicopters have a small tail rotor, to counteract the rotational force.  Coaxial dual-rotor designs solve the rotational force problem by spinning two rotors in opposite directions, but this reduces the total lifting force.  Multi-rotor copters, with four or more independent rotors, solve the rotational problem by spinning half the rotors in a clockwise rotation and the other rotors in counter-clockwise rotation.

I expect (but have not verified) that all of the copters listed above are capable of lifting a small camera.  In the cases of some smaller copters, I had doubts and so did not include those in this list.

Please note that most of these copters will rely upon rechargeable LiPo batteries, for which I offer two tips.  A single battery might give you eight minutes of flight or twenty minutes of flight – so do have more than one battery.  These batteries are relatively high power devices and there have been stories of such batteries causing fire, sometimes during the charging process.  Do use protective LiPo storage bags such as LiPo Safe.

The most commonly used camera for these copters is a GoPro 3 or newer (e.g. Go Pro 3, Go Pro 3+, or GoPro 4).  Personally, I have used the Hero 3+ Black Edition; while I find that it captures great video, I am not impressed by the still image JPEGs.  Listed here are some of the available small “action cameras”, all of which I expect are primarily intended for video.

  • CamOne Infinity
  • Contour+2
  • ContourROAM3
  • Drift Ghost-S
  • Garmin VIRB Elite
  • Gear-Pro HD Sport Action Camera
  • GoPro HERO3+
  • GoPro HERO4
  • Ion Air Pro 3
  • JVC GC-XA2
  • Mobius Action Camera Pro
  • Polaroid XS100i
  • Polaroid Cube
  • Replay XD Prime X
  • Sony AS20
  • Sony HS100V

The last component for aerial photography is perhaps the first component to select when building a new system.  A motorized/computerized gimbal is necessary for aerial video, to remove the unwanted effects of aircraft movement.  The gimbal holds the camera, detects aircraft movement, and automatically moves the camera to counteract the aircraft movement.  Without one of these devices, your level horizon will be ruined anytime the copter moves left or right.  Gimbals are often designed to match the size and weight of specific cameras.  So, if you are thinking of using a specific camera, you need to be sure that you can get a gimbal that accommodates that camera.