With the recent release of the runcam 2 and foxeer legend 1 HD action cameras we are spoiled for choice. They are offered for similar prices with similar specs, so the inevitable question is which is better? I am here to run you through the comparison.
Runcam have been around for some time, and achieved great success with their first runcam HD camera. The new version is an improvement over the previous version both in terms of image quality (1080p at 60fps) and features, wifi and smartphone app.
Foxeer are a new player in the FPV game with the legend 1 being their first HD camera. The Legend 1 was released a few months before the Runcam 2, and was one of the first small HD cameras capable of recording at 60fps. The initial reception was rather mediocre, but its great to see that foxeer listen to user feedback and have since released a few firmware updates. The most recent update has drastically improved the image quality and performance assuming you are using a class 10 SD card.
Image Quality
From tests and other reviews there does not seem to be a noticable difference in terms of image quality. Some say that the runcam 2 produces a sharper image, but in my opinion the runcam 2 images are too over sharpened.
for more images check out the great comparison from rcfpvflight.com
The field of view of the runcam 2 is 120 degrees compared to the much wider FOV of the foxeer at 166 degrees. Which is better comes largely down to user preference. Typically for an action camera I think having a wider FOV is more desirable, but it does distort things abit more which could take some getting used to for FPV flying if you are used to smaller FOV cameras.
Many of the first foxeer legend 1 users complained about the poor video quality, and also some issues with missing frames during recording. However since then foxeer have released a series of firmware upgrades to address these issues. Its also worth noting that the foxeer legend can actually record 1296P Super HD videos at 30fps if you enable this mode via the PC app.
Latency
In our FPV camera guide, we discussed why low latency is so important for FPV racing. So its nice to hear that low latency is one of the features of the runcam 2. The latency is claimed to be 60ms when recording at 1080P, which is probably abit high for FPV racing. But if you are happy recording at 720P the latency drops to 40ms on average which is very comparable to some dedicated FPV cameras.
The Foxeer Legend 1 has a latency of around 100ms which is not great, although it is noticable faster than other cameras such as the gopro which have a latency of around 160ms.
Price 
Currently both cameras retail for the same price at around $99 or £75 (when you count VAT).
Size and Weight
Both the foxeer and runcam 2 weight 49g, which is remarkably light for a full HD camera. However the nice thing about the runcam 2 is that you can remove the battery and power it separately via your flight battery which does save some weight if you are flying on a mini FPV quadcopter, brining the total weight down to 35g.
Specifications
Foxeer are much more open about their camera specifications as they say it runs an ambarella image processor (same company that makes Gopro image processing chips), and the actual sensor is a 16MP Sony Examor R BSI sensor. I could not find any details of the image processor or sensor on the runcam. However both record the same resolution video with the maximum being 1080P at 60 frames per second.
RunCam 2 HD Specifications
Foxeer Legend 1 Specifications
Extra Features
The most notable thing that sets the foxeer apart from the runcam is the fact that it lets you control when to start or stop recording videos or taking photos via your R/C control which is ideal for certain situations. On the other-hand the runcam2 includes integrated wifi with an android/IOS APP which lets you setup, and set the parameters of your camera with ease.
Otherwise both cameras include a cable to allow for video output that you can connect to your FPV transmitter, and a USB cable to charge the battery.
Foxeer Legend 1 Video Overview
For more details on the remote control features of the foxeer, and how to set it up check out this great overview video:
Runcam 2 Video Overview
And likewise here is a in depth overview video of the runcam 2 which also shows you the wifi smartphone apps which is great for setting things up and fine tuning the camera parameters.
Bottom Line
Both cameras are great options for recording for flight with the image quality being quite similar. The runcam 2 wins in terms of latency, making it suitable to using it as a dedicated FPV camera. On the other hand the ability to control the foxeer camera via your R/C controller to take photos, or start and stop recording video makes it great for use on your quadcopter for aerial photography. So if you are looking for a all in once HD camera and FPV camera the Runcam 2 is the best option. But if you prefer to have a camera that you can control while you are flying, the foxeer will be the better option. But as a general add on HD recording camera either will be better than a mobius for recording your FPV racing.