Arguably one of the most important parts of any FPV setup is the FPV camera. The FPV camera is the one item in the FPV system that most directly determines the upper-bound quality of the image that can be transmitted to the pilot.
There are many factors that determine the ultimate quality of the image that is displayed on the pilot’s goggle system or display, but the FPV camera determines the quality of the initial video signal leaving the plane.
Before we offer some tips on which camera to choose, let’s take a look at some of the basic types of FPV cameras.
FPV Camera Types
Small form factor, accessibility of connectors and ease of changing camera settings are all important aspects in choosing an FPV camera. However, more specific technical factors will determine the quality of the image and the utility of the camera in different light and flying environments.
The three main types of FPV camera sensors are CCD, CMOS, and PIXIM.
CCD (charge-coupled device) sensors function by way of transporting the charges of each pixel across the chip and to the corner of the total array of pixels. CCD sensors are manufactured to faithfully reproduce the true image and have low noise.
Compared to CMOS sensors, however, CCD sensors use much more power – up to 100 times as much.
CMOS (complementary metal-oxide semiconductor) sensors are less expensive than CCD sensors because they are much less expensive to manufacture. This may result in an overall cheaper camera price.
CMOS sensors have an advantage over CCD sensors in that each pixel can be read individually. This is due to the fact that CMOS sensors use several transistors at each pixel to amplify charges. Compared to CCD sensors, CMOS sensors have more noise and less light sensitivity.
As CMOS chips use transistors to acquire the charge on each pixel, the fabrication process is much less demanding than for CCD sensors, resulting in lower cost to the end consumer. In recent years however, CMOS cameras have improved to compete competitively with CCD picture quality.
FPV Camera and Stand.
PIXIM sensors have an advantage over CMOS and CCD chips in that they have greater dynamic range and less noise.
The PIXIM sensor is a proprietary technology and relies on digital imaging technology.
These are generally more expensive cameras than CCD or CMOS.
FPV Camera Important Parameters
Below are described some important operating parameters of FPV cameras to aid in choosing the best one for your application.
Resolution for cameras in both color and black and white is denoted by the number of TV lines, and is defined as the number of alternating light and dark lines that can be resolved per picture height.
The higher the number of TV lines, the higher the quality of the camera. There is an upper limit, however, that most video transmitters can transmit. This limit is 525 lines for NTSC and 625 lines for PAL cameras.
In reality, this limit is 483 and 575 lines respectively due to blanking effects and the NTSC and PAL standards of transmission. Therefore, it really doesn’t make sense to purchase a camera with more than 600 TV lines.
More information can be found at the Wikipedia entry on PAL.
The two main types of video standards used for FPV cameras are PAL and NTSC. PAL (Phase Alternating Line) has about a 20% greater resolution than NTSC (National Television System Committee) but has a slightly slower frame rate.
In addition, the PAL standard automatically corrects for tint control, while NTSC requires manual settings. If one can accept a slightly less fluid picture, PAL provides a bit better resolution with increased tint control.
Lens Focal Width
Lens focal width is another important consideration in selecting an FPV camera setup. The focal width size will determine the field of view (FOV) that the camera sees.
Typical focal width sizes are 3.6 mm (90 degrees), 2.8 mm (115 degrees) and 2.1 mm (150 degrees). 2.8 mm is generally considered a reasonable size for normal FPV flying . The lens focal width will impact the low light capability of the camera. Typical “night” FPV lenses are 4 mm in width.
Weight, Cost, and Operating Voltage
The weight of most decent quality FPV cameras is similar and averages about 50 g. This RCGroups thread provides a breakdown of several FPV cameras and their characteristics.
The operating voltage of FPV cameras vary, so it is important to purchase a camera that may be used with the intended video transmitter, and one that ideally will operate at the same voltage. Common operating voltages of FPV cameras are 3.5-5 V and 12 V.