Does a Private Property Owner Have the Right to Shoot Down Your Drone?

Shooting at a Drone is Illegal

Shooting at a Drone is Illegal

Shooting down an aerial drone is a federal crime and could result in criminal liability. Regardless of how a property owner feels about a drone’s (perceived) invasion of privacy over their private property, there are more civil solutions available.

State Privacy Laws Favor Property Owners

We established in our May 2017 blog that case law has favored property owners for altitudes up to 500 feet above their property. So, the wise drone pilot will ensure that they’re flying in accordance with FAA regulations and avoiding any appearance of: (1) the drone is causing a nuisance: (2) being flown recklessly; or (3) violating your state’s privacy laws.

Federal Aviation Laws Favor Drone Pilots

For obvious safety reasons, a drone hit by gunfire could crash, causing injury to persons or damage to property on the ground, or it could collide with other objects in the air. So, shooting at an unmanned aircraft could result in criminal or civil liability, just as firing at a manned airplane. The FAA has cited federal law in their declaration that shooting a drone constitutes a federal crime and could result in criminal liability. Where does it say that?

Federal Law states it in U.S. Code Title 18, Section 32 “Whoever willfully sets fire to, damages, destroys, disables, or wrecks any aircraft in the special aircraft jurisdiction of the United States . . . shall be fined under this title or imprisoned not more than twenty years or both.” Under subsection (c), threatening a drone or a drone operator would also be a federal crime subject to five years in prison.

What if My Drone is Shot Down?

Aerial drone pilots who have an FAA registration number affixed to their aircraft, are Part 107 certified, and flying in accordance with FAA rules will probably have a good case for filing a criminal complaint . . . As long as they’re respecting the rights of property owners! However, case law can go against the drone pilot if it can be shown that they were depriving the property owner of their rights, particularly invasion of privacy.

Summary

Drone pilots must be careful about flying over other people’s property, especially at low altitude. State laws control property rights and in some cases have favored owners for shooting down drones that have been allegedly used for spying. In light of Amazon’s recent approval to deliver small packages by drones, the gray areas between federal and state rights certainly need to be resolved.

Drone pilots should know their rights but also avoid situations that may place their drone in jeopardy. Getting entangled in the legal system is expensive and should be avoided if at all possible.

Don’t miss our next blog on your right to retrieve a drone that lands/crashes onto private property.

Does an Aerial Drone Pilot have the Right to Fly Over Private Property?

Does This Sign Apply to Aerial Drones?

Does This Sign Apply to Aerial Drones?

There’s an altitude limit at which property owners own their airspace. Above that altitude, it’s owned by the federal government. But regardless of altitude, airborne aircraft are always operating under the jurisdiction of the Federal Aviation Administration.

Federal case law first established property owner’s airspace in 1946 as a minimum altitude of 83 feet in a foundational ruling by the U.S. Supreme Court “United States v. Causby, 328 US 266 (1946).” A navigable airspace boundary was later established by Congress as the minimum altitude for aircraft flights – stated as 500 feet above ground level in the “Congress” hotlink. Property rights laws generally accept altitudes below the minimum navigable airspace as the airspace owned by private property owners.

To be clear, the FAA has jurisdiction over all airspace above the ground where aircraft can operate. However, the FAA does not own the airspace below those altitudes defined as navigable airspace.

What Do I Need to Know as a Drone Pilot?

One lengthy legal analysis suggests drone pilots have the right to fly their drones at 400 feet above private property. As you know, 400 feet is also the maximum altitude that drones may operate (with certain exceptions). Note: I couldn’t verify their 400-feet altitude spec, but offer this resource since it cites some good historical information. Whether you’re using 400 feet or 500 feet, current case law favors the property owner if a claim of trespass is made against the pilot.

Does this mean that if you’re doing commercial photography you’re at risk if your drone flies over an adjacent property? Maybe. However, proving loss of the owner’s “full enjoyment of their land” would be difficult if there’s no evidence of: (1) the drone is causing a nuisance: (2) being flown recklessly; or (3) violating your state’s privacy law. In our experience when flying our drone on commercial jobs, it’s very difficult to avoid flying over a neighbor’s private property. So when we’re on a job, we always have a copy of the owner’s (or agent’s) tasking and fly safe.

I’ve been approached by curious neighbors asking what I’m doing with my drone and have found that by explaining the tasking and showing them the drone’s video display it creates a lot of good will. First, they can see that the drone’s wide-angle camera makes it a poor platform for spying. Second, they think it’s very cool to learn about this kind of technology.

This is also a good time to hand out a business card. Sometimes curious neighbors may have a good question down the road, such as “Can I hire you to photograph my property?”

What About Public Lands, Such as the National Parks?

We covered this question in our blog posted on December 7, 2017 “Everything You Never Wanted To Know About Flying Your Drone in the National Parks.” The NPS Director’s Policy Memo 14-05 stated that aerial drones may not be operated from park property, but may be flown over park property (within the FAA’s Part 107 rules). Apparently, federally-owned land managers defer matters of airspace to the FAA.

Summary

Private property owners are within their rights to demand that drone pilots keep their drones away from their property lines. This is a request that responsible drone pilots should respect. Unless a lawful objection has been raised, whenever flying over private property always fly in a safe and professional manner. This will minimize your risk of an unpleasant confrontation and possible legal action.

What Should I Expect To Pay For Aerial Drone Photography Services?

Let’s Start With Some of the Costs of Running a Business . . .

The Business Part of Aerial Drone Photography

The Business Aspect of Aerial Drone Photography

. . . specifically, our drone photography business. There are many operating costs spread across aerial photography operations. They include: drone hardware, accessories, digital camera, camera glide, desktop computer, laptop, tablet, software, office expenses, Internet access, desk phone, mobile phone, aviation liability insurance, FAA certification, transportation, accounting, banking, taxes, etc. These costs are spread across all of our services.

Is a Drone Shoot that Complicated?

We go through a lot of effort to deliver results so you don’t have to deal with these burdens. A hobbyist can go out and buy a drone for less than $500 and then go into “business.” However, that is where the similarity ends. A professional drone operation is so much more than that, so let me explain some of the preparations that go into every drone photography session:

  1. The first step is receiving the task from our client. Through phone conversations and e-mail, we learn about the location and type of photography services desired. (Photography in this article includes videography.)
  2. From there, we look up the location on Google Maps; then check against the FAA’s restricted flight zones. We can fly in certain areas, but others are off limits for drones. Please read our blog.
  3. We then hand-chart the flight requirements onto a hard copy from Google Maps. Tools include self-developed programs to calculate altitudes, speeds, camera tilt angles, fields of view, etc. We know how to translate the client’s requirements into drone commands and can visualize what the camera’s field of view will look like. We’re good at this, very good. Usually, we get our shots on the first try!
  4. Flight requirements are then entered into drone flight programs. We use several, and select the appropriate program for the mission. Some examples: videography, surveying, mapping, etc. Programmed drone flights provide smooth, repeatable missions. This is particularly useful if the client wants us to fly the same mission again, such as for progress reports or seasonal changes.
  5. Driving time to the client’s site is one of our major cost drivers. We need to charge for extra driving time outside our service area.
  6. On site, we look over the terrain for obstacles that may pose a hazard to our drone, such as trees, power lines, light poles, water towers, etc.
  7. The fun part, flying the drone, goes relatively quickly. The preparation steps above help to ensure a successful mission; while collecting the required photography takes less than 20 minutes.
  8. If the client is on site, we download the photography to their computer or give them their files on a USB thumb drive. Otherwise, we upload their files within 24 hours to a cloud service and send them a link. We operate a fee-for-service business, and deliver unlimited copyright with our products.
  9. Returning to the office, we download the files to a desktop computer and back them up onto a storage server. Periodically, we back up client files to BluRay disks and retain them for several years.
  10. Of course, collecting our fees, processing credit cards, accounting, paying taxes, sending receipts, logging flights, etc., all add to the time commitment.

Just a Quick Note on Postprocessing

If the client has asked for postprocessing services, we have a number of high-end desktop programs for photography, videography, and mapping. We’re experts with this software, taking the uncertainty out of the equation and delivering products that meet or exceed the client’s expectations. Examples of our postprocessing products can be found on our Portfolio page.

So, Just How Much Time Do You Spend on a Standard Drone Shoot?

Six hours, which typically breaks down into thirds: (1) Client communications; (2) Mission planning; and (3) Executing the mission. Compared to most other skilled trades, our prices are very reasonable. In the end, we’re in business to earn money, but it just comes down to the fact that we love to fly!

Flying in High Winds – What Could Possibly Go Wrong?

Propeller Spin-off

Wind Gusts Caused This Problem

In this blog, we explain why we limit our flights to wind speeds of 10 mph or less. Seem drastic? Please read on; this is good information.

Drone electronics are quite sophisticated, as they use inertial navigation to stabilize the drone’s camera so it’s almost free from the effects of wind patterns. However, there’s a design limit at which the stabilization reaches the “stops” and no longer holds the camera level.

When the drone is buffeted by gusty winds, the magnitude and direction of the wind can shift quite suddenly. This gives the drone’s stabilization system a workout and sometimes the requirements go beyond the linear operating range. The result is a momentary tilting of the image sent to your remote control. Even with non-gusty winds, the drone’s camera may yaw left or right as the drone’s control system compensates for the wind.

OK, Crooked Photos And Videos; Is That It?

Not really – something much worse can happen when the drone is buffeted by strong gusts: Such as the sudden loss of your drone! The drone’s stabilization system works very hard to keep the camera steady, but when the wind vector tries to tilt the drone, the motors will adjust speed AND DIRECTION, as necessary, to maintain level. If the wind vector is strong enough, one or more motors can momentarily be driven in reverse.

If your propellers screw on, such as the Phantom 3 series, they rotate in a direction that is usually self-tightening. However, if the motor momentarily reverses in a gusty situation then the propeller can actually unscrew and spin-off. The best way to safeguard against a spin-off is to screw the propellers on very tightly. If you’re flying a DJI drone, this means using the supplied wrench.

If your drone uses the new quick release propellers, they can still spin-off, but you’re at a lower risk. Take the Phantom 4, Inspire 2, and Mavic series for example. Their propellers mount with a push and 1/8 of a turn. You (we all) feel safe because there’s a relatively strong spring to hold the propeller in place. However, these drones’ control systems can still drive the motors in reverse. When thrust is reversed and the propeller pushes hard enough against the spring then it will fly-off.

Having some speed on the drone reduces the forces that can drive the motors in reverse. But the pilot should be very careful about low speeds and hovering because these are the conditions that make it more likely that a gust will try to pitch the drone over.

Of course, the best way to safeguard against a spin-off is to avoid flying in high winds. The graphic above was taken from telemetry received from an actual spin-off event.

Why Can’t The Drone Fly With One Propeller Missing?

If a propeller spins off your aerial drone this is what you can expect:

A drone with six or more propellers can survive a one-propeller spin-off. But drones with four propellers are doomed. These drones have two props that rotate clockwise and two that rotate counterclockwise. They were designed this way to cancel the drone’s tendency to rotate. But if you remove one propeller, the drone will go into a spin.

Without a propeller there’s no lift so that corner drops down. So in addition to spin, the drone goes into an uncontrolled roll/pitch. The drone is hopelessly out of control and falls to the earth.

Recommendations

Inspect the propellers before every flight. If you must fly in winds greater than 10 mph, understand that gusts can easily double the wind speed. Take precautions that the propellers are screwed on tightly with a wrench. If you see the image tilting on your remote control, land your drone immediately. Better to fly another day than to take chances on a windy day.

Setting Up Your Aerial Drone Camera

Aerial Drone Camera Options

Aerial Drone Camera Options

Video Formats

When you set up your aerial drone camera to take videos, the first thing you’ll want to do is to select the American standard of NTSC (National Television System Committee).  Your other option is PAL (Phase Alternation by Line), which is more common in Europe, Asia, and Africa. A third standard known as SECAM is also common in Asia and Africa, and your drone may offer it as well. When in the USA, select NTSC. The main difference is frame rate where the American standard is based on 60 Hz and the European standard is based on 50 Hz.

Among your camera’s setting options, you’ll find video size, which allows you to select format and framerate. You can select from 4k for the UHD or Ultimate High Definition (think of Sony’s 4k digital cinema in your movie theater), 2.7k and 1080p (also known as FHD or Full High Definition), and 720p (also known as HD or High Definition).

I recommend setting your video to 1080p, which has a frame resolution of 1920×1080 pixels, and is standard among televisions and computers. Unless you have a requirement to use higher resolution, then 1080p is the standard for you. Higher resolutions, such as 2702×1520 and 4096×2160 are gorgeous if you have the hardware to play them. Their downside is the increased amount of time required to render in video editing software. Another downside is stutter when playing them on less than state-of-the-art hardware.

Recently I compared several of the UHD and FHD video formats and found that my computer monitor displayed all of them, but stuttered when the source was 2.7k or higher. I couldn’t tell any difference in their resolution when compared with standard 1080p, but that would be expected with a 1080p monitor. There was also some stutter when I played a 1080p video at 60 frames per second.

For most videography applications, I recommend using 1080p at 30 frames per second. Eventually the market will move to 2.7k and 4k resolutions, so you should be ready to switch when that time comes.

Photo Formats

Common formats for aerial drone cameras include 12MP (4000×3000 pixels) and 20MP (5280×3956 pixels), which are sufficient resolution for super fine-grain pictures. I have found that the resolution of the sensor is typically greater than the limitation placed on it by the camera’s optics.

Check it out for yourself by blowing up an image in your favorite photo viewing software. You’ll see the image is blurred from pixel to pixel, which was caused by the optics, not the sensor. This is why you want the most direct path for light to enter the image sensor. Due to their small size, these cameras (and their filters) pick up finger prints and smudges that will reduce the resolution of your camera. Inexpensive filters are another contributor to lower resolution.

Three-byte color granularity is known as 24-bit color because there are 8 bits per primary color.  It’s also known as “True Color” or “16.8 million colors” since 2 raised to the 24th power is 16.8 million.  Using our drone’s 12MP image as an example, the resulting image file is 36 million bytes (or 34MB).  Fortunately, cameras compress the images and reduce their file size to perhaps a tenth of their original size. You’re probably already familiar with the common file compression standard created by the Joint Photographic Experts Group and known as JPG.

A drawback of the JPG compression standard is that certain pixels are selectively thrown out. The loss in fidelity is usually negligible. However, the compression process is not reversible so some image quality is permanently lost.

For optimum results, professionals use the camera’s raw mode, which compresses image files without throwing out any pixels. The resulting file sizes are 2-3 times the size of a JPG file, but there’s no sacrifice in image quality. DJI’s aerial drone camera options list RAW, but download in Adobe’s Digital Negative (DNG) format.

For most photography applications, I recommend using the JPG format due to its high popularity. For those special shots (or client requirements) then select raw mode.

Other Aerial Drone Camera Settings

Settings for exposure value, contrast, saturation, color filter, etc. are also available for the experienced photographer. Default values will usually suffice for the casual photographer, but when you’re looking for more control you’ll find it under these settings.

Fly Safe!

Everything You Never Wanted To Know About Flying Your Drone in the National Parks

USA National Park Service

National Park Service Policy On Aerial Drones

Flying aerial drones in the National Parks of the USA was outlawed in June 2014 by the Director of the National Park Service in his Policy Memorandum 14-05.

Several incidents led to this interim policy guidance, which supplements Title 36 Code of Federal Regulations (CFR).  For example, I read reports about amateur drones harassing wildlife, interfering with search and rescue efforts, interfering with fighting forest fires, and in one case a drone that crashed into the Grand Prismatic Spring in Yellowstone National Park.

What You as a Drone Pilot Need to Know

Let’s just get down to the important stuff – what can they do to you if you get caught? Park Rangers are permitted by law to make arrests for violations, and if convicted a drone pilot faces fines and jail time.

So, where does it say that?  Title 36 CFR Part 1.5 and the Policy Memo provide the authority, and 36 CFR Part 1.3 states the penalties, which read: “shall be punished by a fine as provided by law, or imprisonment not exceeding 6 months, or both, and shall be adjudged to pay all costs of the proceedings.”  I’ve also heard of Park Rangers confiscating drones, but I haven’t seen a policy statement granting them that authority.

What parks are covered?  Title 36 covers all lands that fall under the jurisdiction of the National Park Service, including National Parks, National Military Parks, National Monuments, and Battlefield Sites.

Can I Fly Over Other Federal Lands?

Currently, my sources state that you can fly your drone over the National Forests and most lands administered by the Bureau of Land Management.  However, watch for changes in policy as lawmakers are crafting new rules regarding aerial drones.

Process for Permission

For most drone pilots, the bar is simply too high to get a waiver or what the National Park Service calls a Special Use Permit.  The NPS Policy Memorandum outlines the process in Exhibit B. Paraphrased, it states the Park’s Superintendent will receive a written request for proposed drone operations and endorse it up the chain of command to the Associate Director, Visitor and Resource Protection office in Washington, DC for approval.

Are There Any Workarounds?

Once your drone is airborne, your flight falls under FAA rules.  The NPS Policy Memo acknowledges this and states “Launching, landing, or operating an unmanned aircraft from or on lands and waters administered by the NPS is prohibited.”  However, under the FAQ section (no. 9), this prohibition is clarified with a very useful statement that aerial drone flights originating outside the park’s boundary ARE permitted to fly over national park lands (because they’re in the air space that falls under the jurisdiction of the FAA).  I will add that the wise drone pilot will fly strictly in accordance with the safety provisions of the FAA’s 14 CFR Part 107.

Fly Safe!

The Exciting World of Panoramas

Fourteen Individual Photos Were “Stitched” to Make This 360-degree Wide-Angle Panorama

How often have you wished for a wider angle lens to capture your subject of interest? Or have you seen wide angle panoramas and thought to yourself “That’s cool, I wonder how they did that?” Let’s take a look at how to make panoramas that provide a poster-size photo of your subject or immerse yourself into a 360-degree wide-angle, or better yet a cylinder or sphere. Virtual immersion is some of the latest technology for real estate marketing, travel, and personal entertainment.

Rules for Panoramas

Depending on zoom setting, eight pictures should be sufficient for a 360-degree panorama. Do some test runs to practice your technique. The general idea is to take a series of horizontal pictures that overlap 10-20 percent. Ditto for vertical panos. Add a row of pictures above (horizon) and below (ground) for a larger panorama. And always:

  • Take pictures from one position (technically, the position of your lens)
  • Lock your camera’s exposure for all pictures

Making Your Panorama

The term for assembling the individual shots into a panorama is “stitching.” Basic stitching software includes Microsoft’s ICE (it’s free). For more professional results, programs such as PT GUI Pro automatically blend the images. Think of the blue sky that varies in intensity from shot to shot. Automatic blending provides a pleasant transition from lighter to darker shades of blue.

Can I Control Where The Stitches Are?

Good stitching software will give you control over where the images get stitched. Say you have 20 degrees of overlap, but an object is in motion in both images. For example, a car is in position A in one image and position B in the other image. You select which image to dominate through masking, and the other will disappear. As long as you have adequate overlap, the images can be successfully stitched.

Spherical Panoramas

Use the software’s “Layers” option to create the file set for a spherical projection. Then use Tools/Publish to Website, add these files and hit the convert button to build the web file set. Upload these files to a web folder and copy the link to the master file “name.htm”. (You will see a lot of image files, each with small portions of the pano; this is normal.) Insert the link wherever you desire and the spherical panorama will come up when viewed in your browser. Use your mouse to move around the pano. This is how the professionals do it for real estate portfolios, FaceBook, etc.

Here’s an example of a spherical panorama we made with 26 images: Monument Valley

Other Practical Uses

As I mentioned above, panoramas can be used to make super wide angle photos. If you can’t position yourself far enough away from your subject, then take multiple images of it and stitch them together. Do you have a large print or poster that’s too large for your scanner? Scan it in sections and stitch them together for a high-resolution image file that’s much better than taking a picture.

Fly Safe!

Balanced Propellers Will Reduce Vibration in your Aerial Drone

Use an instrument like this to ensure your drone has balanced propellers

Balance Your Propellers For The Smoothest Possible Flying Experience

Balanced propellers will reduce the vibrations that transfer to your flying camera as these small movements can result in blurred stills and shaky video.

How Can I Improve the Quality of My Drone’s Photography?

Drone manufacturers have fairly good quality control for their airframes but like any airborne device their smoothness depends on proper balancing of the rotating components. In our case, that would be the propellers. We’ll assume for the moment that the motors and propellers are running true and aerodynamically balanced. More on that below.

First, Why Should the Propellers be Balanced?

Well, why do drivers balance the tires on their cars? Experienced drivers know that unbalanced tires lead to vehicle vibrations when their speed picks up. The same holds true for drone propellers. When one part of the propeller is heavier, the spinning mass delta will cause vibration that increases with speed.

The Solution is Propeller Balancing

To balance the propellers, you’ll need to purchase a balancing kit; example in the picture above. It works by attaching a rod to the propeller and the pair is then balanced on a very low friction support. Any propeller imbalance will cause the propeller to roll until the heaviest part of it hangs below. Balance is achieved by adding or removing material until the propeller is stable.

Here’s the How To:

Place the propeller so it’s horizontal and watch for one side or the other to dip. Then sand/scrape off a small amount of material from the heavier blade such as on the bottom side near the tip. (Or add a little scotch tape to the lighter blade.) Horizontal balancing will take out most of the vibration.

Vertical balancing is next. The concept here is that whatever imbalance that remains is in the hub. Place the propeller so it’s vertical and look for motion. Balance is again achieved by adding or removing material until the propeller is stable, but this time it’s at the hub. If needed, sand/scrape material from the heavy side of the hub, between the propeller blades. This step may take longer because more material typically needs to be removed.

Your propeller is properly balanced when it remains stationary on the support no matter which position the blades are placed.

How Do I Ensure the Propellers are Running True?

Great question and easily answered! Start your drone on an elevated surface, such as a table, but don’t take off. Then observe the blade tips, looking for spread. There will be little to no spread if the blades are running true, which means they’re aerodynamically balanced.

If there’s spread between the tips, then the blades have different amounts of lift or the motor/shaft are bent. This means that your propeller is aerodynamically unbalanced, causing vibration. Typically, the culprit will be just one of the propellers so you can rule out a bent motor by swapping the propellers (e.g. exchanging one black hub propeller with the other). If whatever spread you saw on the one side does the same thing on the other, then the propeller is bad.

Balanced propellers will lead to the smoothest possible photography with your drone. Whatever residual vibration that appears in your video can be taken out with post-processing software.

Fly Safe!

Video Production and Post-Processing

Video Production and Post-Processing

Example of a Video Editor Timeline

Video production and post-processing are where the video and photo clips are assembled into a composite video. This is where the art of taking pictures meets the art of developing a deliverable product that meets the expectations of the client.

What is typically done in Video Production and Post-Processing?

Videos, photos, voice, and music components are planned and then sequenced into the software’s timeline. Each component has a time associated with it, so the sequence is planned from beginning to end with a target run length. For a specific run length, video segments are cut to the desired length and photos added/removed for a pleasant balance.

Post-Processing is challenging, but is key to achieving great results. In addition to assembling the components, there are special effects that include cropping, adding motion to photographs, reducing shake and vibration, adjusting brightness, contrast, color density, etc. Sometimes, a voice or music track is not needed, but other times they’re critical to finish that perfect video.

Once the video has been assembled, it is rendered – or processed into the feature video. Rendering is processor-intensive and can take as long as several times the finished run length.

Tell Me More about the Sound Track:

As you know, aerial drones don’t record audio. For many productions, this is OK because the finished video doesn’t require a sound track. For example, the business person is in an open office space where the audio can be distracting to others.  A target audience like this is looking for information – and subtitles will suffice.

There are other productions where a sound track is preferred and, fortunately, video mastering software makes adding a sound track relatively easy. The hard part is getting the audio track, whether it’s the client’s voice recording or a specific music request. You’ll want to work closely with the client at this stage as the process works best when he/she understands what is needed and provides the voice and music files.

In my experience, manipulating the visual media is the easy part. Sound, on the other hand, can run into multiple iterations with each requiring another rendering and submittal for approval.

Visit our Portfolio page for examples of the different types of sound tracks.

Should I be concerned about Copyrighted Material?

We must respect copyrighted material, whether it’s video or audio. So, although it may be easy to copy a track from our favorite CD/DVD, there’s also the risk of getting discovered and forced to pay. Detection methods are now being used to track unlicensed usage of media, and copyright owners love to demand outrageous prices when someone gets caught. It’s always best to purchase the license and have a clear conscience.

I could spend a lot more time on copyrighted media, with some horror stories to go along with it. For now, let’s stop here and I’ll follow up later with a more detailed blog.

Fly Safe!

You Don’t Have to Know Trigonometry to Plan a Drone Shoot, But It Helps

Image of trigonometry for a drone shoot.

Learn Useful Information By Applying Your Camera’s Field Of View Specification

Here are some tips on how a little trigonometry can help you to improve your drone shoots. Most Virginia drone pilots can fly to a position that “looks right” in their display for taking photos and videos, but what about those large jobs, such as a hundred-acre tract of property?

I recently had a commercial session involving the marketing of 116 acres of undeveloped land. My usual preplanning (and pre-programming the aircraft) was a little more challenging because I wanted to fly at the right altitude, the right speed, and the right camera tilt in order to minimize the “trial and error” approach to videography.

I’ll be happy to talk off-line about the actual formulas, but to keep this post as brief as possible I’ll just outline the principles. The fundamental information you’ll need is your camera’s field of view (FOV) and the frame’s aspect ratio. For example, the DJI Phantom drone’s FOV is 94 degrees and its aspect ratio is 4:3 for photos, and 16:9 for videos.

For 4:3 photos, the trig results are approximately 75 deg horizontal FOV and 56 deg vertical FOV. (Approximate because this is a two-dimensional approximation of a 3-D device.) These results are shown graphically in the figure above. For 16:9 videos, the horizontal FOV is about 7 deg wider (82 deg), and the vertical FOV is about 10 deg narrower (46 deg).

With this information, you can calculate the field of view for any given distance. Say you’re shooting a photo straight down from an altitude of 100 feet. Using the sine and cosine functions, the horizontal FOV is 122 ft and the vertical FOV is 95 ft – or – a rectangle 122 x 95 ft. This is suitable if your subject, say a house, is around 60 ft wide. This ratio stays the same, so at a distance of 200 ft, the rectangle scales up to 244 x 190 ft.

Another useful angle is the tilt required to put the top of the frame just below the horizon. We found out above that the vertical FOV is 56 deg. With the camera’s tilt at 0 deg, the horizon is centered in the view. Therefore, the top and bottom of the view are at 0 deg plus/minus 28 deg. So, in theory a camera tilt of -28 deg should put the horizon at the top edge of the camera’s view. For 16:9 video, the horizon (again in theory) is at about -23 deg. In practice, I use a tilt of -30 deg for photos and -26 deg for videos to ensure landscape pictures aren’t turned into silhouettes by the bright sky.

Another tip: Use algebra to solve the time required to run a certain distance at a given speed. This will help you determine how much air time will be required per run and, thus, how many batteries to bring.

These concepts are approximate and you may come up with different results. Regardless, a reasonably disciplined approach will help you plan your flying sessions.

Fly Safe!