We have received several readers’ requests to explain the differences between electronic and mechanical shutters during this summer. We thought it would be helpful to compile our answers to queries about camera features in aerial photography, the basics explained.
- Mega pixels and semiconductor points
Behind the lens of a digital camera is a surface containing semiconductor points. A semiconductor point where light can be measured is a pixel. A million pixels is a mega pixel. The camera electronics determine when the semiconductor points will be measured, for how long they will be measured, and how much light will need to shine on the point to cause that pixel to be considered “on”.
Digital cameras do not have shutter. Light shines in through the lens to the semiconductor surface in the camera. The electronics in the camera measure the light shining on the surface for a certain period of time. This is equivalent to the time that the shutter would be open in a film based camera. When the camera is not taking a picture, light still reaches the surface, but the camera electronics are not measuring it.
The ISO rating for the film is also handled electronically in a digital camera. The electronics in the camera can be adjusted so that the camera’s sensitivity to light shining on a single semiconductor (pixel) can be controlled. Thus, if you set the camera to have an ISO 400 rating, the camera takes less light to set the pixel to “on” than when the camera has an ISO 100 rating.
The film based cameras needed a lens based technology to obtain a close-up image of a remote object. Digital cameras can simply use a smaller part of semiconductor surface and enlarge that area in the image which is ultimately recorded. The result is an electronic telephoto effect. Digital cameras can take pictures in narrow, wide or extra wide mode using very similar features.
The term f-stop refers to the focal length divided by the aperture. Most film type lens systems have an adjustable diaphragm to allow for more or less light to enter the camera. This adjustment is not needed in a digital camera because the electronics can easily adjust the sensitivity to light to accomplish much the same result. While f-stop can still be used in digital cameras, as a matter of practicality, it is of much less importance.
Here are some professional camera features to consider in aerial photography:
- Camera Frame
The camera has to mount to the quadcopter. Phantom 4 DJI has their own proprietary camera frame. There are people who have made adapters and you may be able to buy an adapter if needed. There are a number of people have managed to mount other cameras, but it seems that they make their own mounts (3D printers are mentioned.) Most other quadcopters are designed to hold GOPRO cameras.
- Focal length of lens / auto focus
Most of the GoPro cameras have a fixed focal length of infinity. This focal length provides a good quality image most of the time. If you need excellent quality and you think that the lens is the problem, you should probably consider moving from the GOPRO frame to a different frame. Before you do an outright switch, consider the fact that if you change to a different frame and lens you will be using a non-standard rig which will probably not provide the best quality most of the time, just for your special purpose.
There are a few thing to think about in terms of the lens. The standard 4 mm lens lets in less light than a 20mm lens. This matters when you have telephoto lens attached. I don’t see the need for a telephoto lens on a quadcopter. If you need a closer view, you can either fly the quadcopter closer or adjust the electronics to obtain a narrower field of view (FOV). If you see the need for a telephoto lens, of course you will need a bigger lens, 20mm up to 150mm are available. The telephoto lens has a much narrower field of view.
A wider FOV can also be important. The GOPRO camera has a function that allows electronic control of the FOV (to some extent). The feature allows the user to select narrow, wide, or extra wide angle. While this is not exactly the same as FOV, it is close enough that we can work with them the same way. Any shots made with extra wide angle or a lens with a wide FOV will almost certainly have a fish-eye effect on the image (straight lines at the edge of the image appear curved). This can be fixed with a post-processor, like Photoshop. If an even wider image is desired there are fish eye lens’ available.
- HD video cameras
The rule of thumb for HD Video cameras is, the more mega pixels, the better quality image you can produce. You can still mess it up (I know that I have), but you will never produce really high quality with only 2MP. Getting the really nice high quality shots takes practice, nice steady platform and lots of pixels. I see professional grade cameras offered with 10MP, 12MP. Look for 1080p at 30 fps or better.
- HD still cameras
I always try to shoot in 4k mode when I can. I know that I can always reduce the number of pixels if I want to, but you can’t get more. If you want to/need to put the image up on a screen as you would in a presentation, you will want 4k if you can get it.
- Standard GoPro features
The time lapse feature on the GoPro produces some interesting sequences. If you see the use of time lapse, be sure to get the “interval timer” feature and then you will be able to shoot these sequences.
The ISO speed of the camera is important when we talk about shooting pictures in less than ideal lighting. My old film camera took ISO 100 – 1600 and would automatically adjust the f stop to accommodate the film speed. The new digital cameras have even more range. In some cameras, you can select an ISO anywhere from 100 to 3200. Choose a higher ISO for lower light. This forces a faster shutter speed and you will get less blurry images. Also choose a higher ISO if you want a higher number frames per second. Choose a lower ISO for bright sunny day and higher quality images.
The burst mode can be useful when shooting an event (for example a wedding). You might trigger the burst mode when the bride and groom start walking down the aisle after their vows to high light this part of the event. (I assume that you are not going to actually fly over people. Quadcopters do crash, and a crash on someone’s head would really spoil the wedding.)
- Thermal imaging
Thermal images are often needed in agricultural and law enforcement applications. The thermal images of a crop often reveal infestations and differences in watering. Thermal images also help to spot a fleeing suspect or a hiding person. Thermal imaging is not standard on the GoPro cameras but these modified cameras are available.
FLIR has a nice line of thermal imaging cameras. The FLIR camera can be mounted on an Inspire 1 with this adapter. The power company was out in my neighborhood recently. The power company tech showed me his little hand held FLIR image viewer which he used for close work. He checks our local underground vaults every three years. The power company uses someone else to pilot drones to check the thermal images on the high voltage lines.
- Night vision
Other night vision equipment does not seem to be engineered for drones. Pulsar and Sightmark both have excellent equipment for rifle sights. Maybe someone will develop an adapter kit so we can use their equipment on our drones.
Multi-spectral cameras record both visible spectrum and IR. The PrecesionHawk is an example of a multi-spectral camera drone. Precisionhawk is an aerial agricultural analytics system – using DJI’s commercial-grade drone hardware and PrecisionHawk’s drone software platform (DataMapper).
Whether you are a professional aerial photographer or a hobbyist who likes to shoot professional-grade aerial photographs, buying a high performance camera drone is a substantial investment. What kind of high-performance drone-rig features you need depends on your purpose and how you are planning to use it. Checkout out our planning checklist to help you select a professional-grade camera drone.
Here are our top picks for professional-grade camera drones for aerial photography
DJI Phantom 4. This is the most popular drone on the market. Read our review. It is well suited to almost all amateur needs and most professional needs. This copter provides a most stable platform for videography. Its ability to enter a flight plan allows you to visually plan your flight path, overlay waypoints onto a visual map of your flight area.
- SHIP FROM SURE RC! Avoid obstacles automatically in the front direction. Track moving...
- SHIP FROM SURE RC! TapFly lets you fly with a tap of the finger. Smart Return Home...
- SHIP FROM SURE RC! 28 minute maximum flight time, maximum control range of 3.1mi...
- SHIP FROM SURE RC! Integrated gimbal for greater camera stability and smoother...
Typhoon Q500 4K RTF Quadcopter.The Q500 4K RTF Quadcopter is one of our top picks for high-performance camera drone under $800. Read our review on Typhoon Q500 4K RTF Quadcopter. It is a professional grade quadcopter with an integrated 3-axis anti-vibration CGO3 gimbal. The Typhoon Q500 comes factory-assembled, already test-flown, it is ready to fly and shoot videography out of the box. The Q500 is a tech gift more than $500 but it is one of the most complete drone bundle you can get for the money. We also like the ST10+ personal ground station – a 10-channel 2.4GHz RC transmitter that supports a 5.8GHz video downlink delivering streaming video to the built-in screen. Another great feature of the Q500 is the modularity of the SteadyGrip handheld device – it extends the perspective from the sky to the ground with CGO3 mobile app. The Q500 comes packaged in its own rugged lightweight-aluminum transport case. This is one of the best buys to capture 4K from aerial and ground for your professional projects or personal vacation shoots.
- The Typhoon Q500 4K arrives factory-assembled, test-flown, ready to fly and film out...
- The 3-axis anti-vibration CGO3 gimbal camera and the optimized fixed focus lens...
- The ST10+ personal ground station is a 10-channel 2.4GHz RC transmitter that supports...
3DR Solo. If you already have your own GoPro or Hero 3, 3+ or 4, this copter may be just right for you. Read our review. This quadcopter has all of the features needed by almost all amateur needs and most professional photographers. This quadcopter has orbit and selfie modes and is slightly less expensive than similar quadcopters. This quadcopter is especially suited for people shooting events (such as weddings, family reunions and back yard games) and real estate agents shooting videos of properties.
- Solo Drone Quadcopter With all Manufacturer-supplied Accessories + Full USA...
- 3D Robotics GB11A 3DR Solo Gimbal (Black), GoPro HERO4 BLACK
- Lexar High-Performance microSDHC 633x 32GB UHS-I
- 3D Robotics PP11A 3DR Solo Propeller Set - Black (Black), Polaroid 5 Piece Camera...
Check out our review series on camera drones.