Finding the right camera for aerial photography is a mixture of trial and error combined with some practical considerations. While the capability of small format sports cameras such as the GoPro™ have improved dramatically, they are designed primarily for video rather than still shots, so my preference is to use small compact point-and-shoot cameras for aerial photography. On the practical side, small size and low weight (between 100-200g) are obviously important, and the ability to provide a live video output is a benefit in being able to frame a shot (see below). Below are some of the cameras I use together with the features that I have found make them a good choice for aerial photography.
Fuji F20
The F20 first came on the market in 2006 and is no longer available in shops although can be found on eBay. Despite having only a 6 mega pixels the sensor is particularly good in low light, and together with its Fujinon lens creates exceptional pictures across a wide range of conditions in auto mode. Colour and exposure are very good on this camera. Its aluminium case makes it quite rugged although reasoably light (155g), mine having been ejected from the plane several times due to crashes, but still works flawlessly. Live video-out is available through the USB port and a saddle with the servos to trigger the camera and turn it on and off can easily be attached with rubber-bands as illustrated on the Radian page here. Other similar models are the F30 and F31.
Canon Powershot A640
The A640 was on the market around the same time as the F20 above, so is also relatively old technology but can still be found on eBay. With 10 megapixels and a range of manual options it was intended to be an upgrade to the F20, but in reality I still find myself using the F20 much more. One reason is the A640 is significantly larger and heavier (250g) than the F20 making it difficult to fit into existing planes - this turned out to be the main motivation for designing the Platform. A further motivation was the use of CHDK as a means of controlling the camera, something that most Canon cameras can do, and which also allow them to shoot in RAW format as well as JPEG. The A640 has live video-out and is powered by the flight battery to save weight.
Canon Powershot S90
When the S90 came out in 2009 it was pitched at the high end of the compact market with a range of both automatic and programmable features. Its 10 mega pixel sensor and optics make it capable of very good images. It is lighter (200g) than the A640 and smaller, having a footprint not much larger than F20 which allows it to better fit into confined spaces, and means that it can be used in both the Radian glider and the Platform. It has live video-out, will run CHDK, and will take both RAW and JPEG format images.
Mobius Actioncam
The Mobius is a light, small format action camera designed for recording good quality video to an on-board memory card. It has no screen or viewfinder although it does have video-out through its USB, while the controls consist of just three buttons on the top of the camera along with a multi-colored LED to indicate various modes of operation. A PC program can be used to easily configure the camera which can also take still shots at defined intervals. Its small size and weight make it ideal for use on small aircraft such as the Mini Skywalker.
Camera Remote Control
Most point and shoot cameras have settings that allow pictures to be taken repeatedly with a defined interval that will allow automatic capture of pictures while an aircraft is flying. However, not knowing precisely when a camera is taking a picture can mean that a desired shot is often missed as you guide the aircraft to point the camera at a desired location. So, providing a means by which you can trigger the camera while flying the aircraft gives you control over when you take a photograph, and can be done using the same radio control transmitter and receiver that is used to fly the aircraft.
An aircraft is controlled by the movement of several control surfaces, such as the ailerons (A), elevator (E) and rudder (R), and for powered aircraft, one or more motors (T) that typically drive propellers or have some other form of propulsion. Each of these is independently controlled by a radio ‘channel’ between the transmitter you use to control the aircraft and a receiver in the aircraft itself. These channels are transmitted using a radio signal between the transmitter and receiver.
Frequently, the transmitter and receiver will support more than the 4 channels that are needed to control the motor and control surfaces, and these additional channels can be used to control other functions such as landing gear, lights and so on. In our case, we can use a couple of these additional channels to trigger the camera shutter and optionally turn the camera on and off.
Camera triggering
So how is the camera triggered – what presses the button? There are several ways in which this can happen, the most basic of which is to use a device called a servo which translates the channel signal at the receiver into a movement, typically a rotation of an arm that is normally connected to one of the control surfaces on the aircraft. As the signal increases or decreases according to the joystick movement of the transmitter, the servo arm rotates proportionally and so drives a corresponding movement in the control surface. By taking the servo and attaching it to the camera, the servo arm can be made to activate the shutter as illustrated here. Likewise, another servo (using a different channel) can be used to turn the camera on and off by depressing the on/off switch on the camera.
Attaching servos to cameras may not always be that easy or desirable, particularly if you wish to use the camera as normal. Canon cameras have a way around this with the use of a piece of software called the Canon Hack Development Kit, or CHDK. This software can be loaded onto the memory card of the camera and when it is switched on, will provide an operating system for the camera that, amongst other things, can allow the camera to be controlled through its USB port. CHDK has built-in functions to allow the shutter and zoom to be automatically controlled through the USB port, or you can write your own scripts in a BASIC-like language to implement your own control of the camera. With a small piece of electronics that converts the servo signals from the receiver to the correct signals on the USB interface, the camera can be controlled without the need to attach servos to it.
A further benefit of CHDK is that it allows any Canon camera to shoot in RAW format rather than JPEG which allows a greater degree of post processing images using programs such as Rawtherapee and Darktable.
CHDK
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Servo Trigger
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Framing the shot
Seeing what the camera sees in the air helps to be able to capture the right shot, so if the camera has a 'live video-out' capability its view can be transmitted to the ground from the aircraft using a small video transmitter. The video transmitter will need to operate in a different frequency range to that of the radio-control transmitter to avoid interference, and for relatively short distances over several hundreds of meters, there are plenty of low-power transmitters available in the 5.8GHz band. It is important to use a good antenna, preferably a circularly polarised 'mushroom' antenna that will reduce multi-path distortion for a clearer image on the ground.
On the ground, an equivalent receiver and antenna is used together with a video screen to see what the camera sees. Watching this while flying the aircraft takes a bit of getting used to, and I typically work with a the screen attached to the top of the rc-transmitter that allows me to both keep my view on the aircraft in the sky while occasionally glancing down to frame the shot. Alternatively, one can use a screen attached to a tripod if others are keen to get a birds-eye view, or use video goggles for a more immersive experience.
Tripod Monitor
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Transmitter Monitor
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Goggles
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