The Canon PowerShot line has gained some popularity
as they can be obtained rather inexpensively and
augmented with the Canon Hack Development Kit (CHDK)
to add many new features ( http://chdk.wikia.com/wiki/
CHDK). You can even write and run Lua scripts on the
camera! I would recommend looking for a camera with
integrated GPS or external GPS capability, interval shooting,
and the largest sensor you can find.
Another popular category is the interchangeable lens
cameras. Formerly, I would have limited the discussion to
single lens reflex (SLR) cameras, but the prosumer market
has evolved to put some really nice technologies in the price
range of hobbyists.
Beginning with SLRs, we get into the range of many
hundreds to a few thousand dollars for the newest
equipment. These cameras are sold as a body and lenses,
generally purchased separately. SLRs use a mirror and prism
set that lets the photographer see the image through the
lens of the camera optically, without the need to look at a
screen that can be difficult to see in bright conditions.
Due to all of the moving parts, SLRs are larger and
heavier than their point-and-shoot counterparts, but
generally have larger sensors and are much more feature
rich. The newer mirrorless interchangeable lens cameras
(MILCs) are at a similar price point, but have a form factor
more similar to that of a point-and-shoot. The Sony NEX-
5R/B is available used for a few hundred dollars and could
make a good entry level camera. The Sony A7S has good
reviews as well and is a full-frame sensor camera, but retails
for around $2,200.
Lastly, we have to briefly discuss triggering of the
camera. Some fully integrated systems allow the flight
controller to control the camera. This means that the
operator can pre-program the exact positions at which to
take a photo so that the dataset has the correct amount of
overlap and no excess information that will slow down the
processing of the images. Most of us will be dealing
with a more homemade system that doesn’t have
such tight hardware-software integration. Some prefer to
utilize the infrared remote trigger functionality of their
camera and create a system that can trigger the shutter;
others record video and extract still frames.
The simplest route is to set up an intervalometer, or
timed shutter. With an intervalometer, the user sets a delay
(say two seconds) and once the camera is triggered, a
photo will be taken at intervals set by the delay. Many
cameras have this functionality, or can be hacked with
alternate firmware (like CHDK) to add it.
For my first try at collecting aerial photogrammetry
data, I went with my inexpensive “GeekPro” knockoff
camera (Figure 2). This unit takes stills and video, came
with a variety of accessories (Figure 3) and a case, and is
app-enabled — all for less than $100! While the photos are
not impressive, it is perfect for a low-risk experiment. I have
an older (2007) Nikon D40x (Figure 4) that I’d like to try
sometime, but I didn’t want to build a mount for it and risk
damaging it until I knew what I was doing.
My first idea was to 3D print a bracket for the Faux Pro,
SERVO 05.2017 13
Figure 2: The “Faux Pro” camera I found on sale for less than
$100. It looks and operates very similar to the real GoPro
products, but has fewer features and less battery life.
Figure 4: The Nikon D40x is an aging but high quality DSLR that can be
augmented with GPS tagging of photos for a nice aerial photography setup.
Figure 3: This action camera came with a wide variety of mounting
options and a protective case. Assembling the different mounting
brackets was a bit of a puzzle.