One of the most important components in FPV flying is the fpv camera. If the camera is not good enough for the purpose, it has effect on the whole flight.
- sensor type – CCD or CMOS
- video standard – PAL or NTSC
- field of view
- lens brightness (F number)
- night vision by light amplifier electronics (starlight, …)
- IR filter presence
- changing light conditions (reaction time)
- picture stability depending on the voltage fluctuations
- noisy components of the camera (RF noise)
* sensor type
Vast majority of todays cameras have a CCD sensor, but the number of cameras with CMOS is rapidly growing. The advantage of the CCD sensors over CMOS is that there is no “rolling shutter” effect on CCD cameras. On the other side, the CMOS cameras have higher resolutions, thus, nice picture. Note that the maximum horizontal lines that the analog transmitter can transmit is 576, but the vertical resolution with the CMOS can be more than 720 (SD standard), so the transmitted picture is finally better. The light handling of the modern CMOS fpv cameras is comparable to the CCD ones, if not better.
* video standard
There are two major types of video standards that we use FPV cameras: PAL and NTSC. While the former has slightly bigger resolution, the latter has slightly slower frame rate.
PAL: 625 lines (576i – 576 visible lines) @ 50Hz (25FPS)
NTSC: 525 lines (480i – 480 visible lines) @ 60Hz (30FPS)
For fpv cameras, we usually choose PAL, because of the higher resolution. As the upper limit for the video signal transceivers is 576, that is the maximum theoretical resolution of ANY fpv camera that is worth to use (600TVL). Practically, this is not completely true.
Camera resolutions are specified as TVL (TV lines) and go from 480 up to 1000. Usually, the higher the TVL value, the better the picture, however, because of the mentioned limit (SD quality@analog transmitters) many say there is no reason to buy camera with a resolution higher than 600TVL. This is not completely true, as stated above, because the TVL number specifies the horizontal resolution only and even the analog transmission can get us better picture on the ground.
* FOV (field of view, angle)
The FOV or camera angle gives us information how much angle the camera sees. The values are given in “mm” which equals to the focal length. The lesser the number, the wider the angle. The cameras that are generally used in FPV has 2.8mm lens that gives us around 90 degree angle horizontal and 80 degree angle vertical. By using a 3.6mm lens this decreases to 75/65 degrees. The more narrow the angle, the more details we see on the picture.
Usually, when there is no fast movement and we need to see as much picture as possible, we use 2.1/2.8mm lens, and when doing proximity flying and need to see more details then we choose 3.6mm lens.
* lens brightness
The lesser number the better (Fx). The better the brightness the better the camera sees by evening and/or night.
* night vision
For night flying we use cameras that have very low LUX ratings. A camera below 0.001 LUX can see nearly perfectly in the dark night. There are some cameras even below this value, sometimes called “starlight cameras” (0.00008lux in BW mode). These cameras usually do not contain an IR filter, for obvious reason.
* IR filter presence
The IR filter is a small crystal that is positioned between the lens and the sensor. The purpose is to filter out near IR radiation. By doing so, the picture is more vivid (better colors) during the daylight. On the other side, IR filtering means that the camera will not see as good in low light conditions.
Kind of IR filtering can also be added as an extra coating on the lens.
For daylight cameras we usually always request the IR filter (check at seller before buying) and for low light cameras we do not need it, as the intention is to get as much light through the lens as possible.
* changing light conditions
Typical problem with low cost cameras is when turning the camera towards the bright sky, the ground will be very dark so we can not see nothing. Other problem is when turning the camera towards the sun, and we got a bunch of IR, haveing everything too bright to see the details. There are some techniques to compensate for light changes, these are known as “BLC” (backlight compensation) and WDR (wide dynamic range). Before buying a new camera, always check for the presence of these, to avoid problems with dynamic light changes.
Note that not all the BLC technologies are equally good, and there is also a D-WDR (digital WDR) technology, which is kinda emulation of WDR on cheaper cameras. Avoid these. Buy only cameras that were proofed or reviewed by other users and found to be suitable.
Beside of these, the reaction time of the camera for the light condition changes is very important too. The faster the better.
* noisy components (RF radiation)
Unfortunately some cameras components emit unwanted RF radiation. This is mainly in the sub GHz segment, and can affect some LRS systems that are running around 433MHz frequencies. There is no way to find it out before buying, so when planning an fpv camera for a LRS powered copter, always check the reviews of another users, to find out whether the camera is suitable. In most cases even the metal casing of the camera is not enough to filter the radiation.