What drone pilots see while they are flying, are the low latency video from analog FPV cameras. To choose the best FPV camera for your multirotors, there are a few things to consider which we will discuss in this post.
FPV camera is one of the most important parts of a quadcopter FPV setup. Real-time image from the camera is broadcast through a video transmitter. Regardless what video transmitter you have, the image you see on the FPV display is only as good as your FPV camera. in this post I will give a tutorial on how to choose an FPV camera that fits your drone needs
The Types of Imaging Sensor
CCD and CMOS are two main types of image sensors in FPV cameras, each with unique characteristics and advantages.
CCD is an older technology and used to be the go-to image sensor for FPV cameras. Nowadays most new FPV cameras use CMOS and they are constantly getting better. Here is a summary of the pros and cons, for more detail check out this post about the differences of CCD and CMOS.
- Less jello effect in footage due to global shutter
- Less digital noisy in low light
- Generally warmer colour
- Generally lower in latency (the good ones)
- Higher resolution, but also can have more digital noise
- More natural image colour
- Low light / Night FPV cameras tend to use CMOS sensors
- Generally cheaper to make – therefore the cheapest FPV cameras are usually CMOS
- More susceptible to jello due to rolling shutter
There are 2 aspect ratio to choose from in FPV cameras, 4:3 and 16:9. Aspect ratio has nothing to do with resolution, it’s just the different screen shape.
4:3 is more square and has the shape of an old CRT TV while 16:9 is longer like a modern computer monitor.
One isn’t always better than the other, it all comes down to which ratio your FPV goggles or display supports. If you have a 4:3 camera, but your goggles is 16:9, the image will appear stretched. If you have a 16:9 camera but a 4:3 display, the image will appear squashed.
Aspect ratio isn’t directly related to the peripheral view, e.g. 16:9 camera doesn’t necessarily give you a wider field of view. It actually depends on the lens and image sensor of your camera, which we will talk about later.
But it’s worth knowing that CMOS sensors have a native aspect ratio of 16:9, while that of the CCD is 4:3. Some CMOS cameras allow you to choose between 16:9 and 4:3 in the setting, but the 4:3 is achieved by chopping off the sides from a 16:9 image, and therefore you will get a smaller field of view in 4:3.
FPV camera lenses are different in two main things: focal length and thread size.
Focal length changes the field of view (FOV) of the image, the lower the focal length, the wider the FOV. To give you some idea, here is a rough estimation :
Wide Dynamic Range (WDR)
Wide Dynamic Range (WDR) is a technology that aims to improve image detail under extreme lighting conditions where both bright and dark areas are present in the same frame.
As you can see the image on the left it’s under exposed, you can see the sun and clouds very well, but the tree and bushes are all dark. On the right we have an image that is slightly over exposed, the trees are all visible now but the sky is blown out. The image in the middle represents the best wide dynamic rangeof the three images, you can see the clouds and the car at the same time.
Once you understand the concept you will begin to appreciate the importance of WDR capability in FPV cameras because it helps you see better when flying. Most FPV cameras have some degree of WDR, but the WDR performance can vary.
FPV Camera Resolution (tvl)
TVL (TV Lines) is what manufacturers use to measure analogue FPV camera resolution.
The number is based on how many alternating black and white lines can be displayed in the image horizontally. A 600TVL camera means it can display 300 black lines and 300 white lines alternately in one frame. The more TV lines, the better definition image you can get out of the camera. Commonly seen FPV cameras TVL are 600, 700, 800 and 1200.
However higher TVL doesn’t always give you better image due to the limitation of analog 5.8Ghz video transmission, as well as your monitor or FPV goggles. For example, 1200TVL is not going to be twice as sharp comparing to 600TVL in an analogue FPV system.
There is no easy way to verify the TVL spec claimed by manufacturers. So don’t be overly concerned about this number when buying an FPV camera, and base your decision on the actual image quality.