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GoPro cameras have become known for their high video quality, and the Session is no exception. Once connect to the app, the camera gives you a good selection of resolutions to choose from, and while these might not be the headline-catching 4K's of the HERO4 Black, they will enable you to edit and view your footage smoothly on a home computer.
The visual quality of the footage is excellent, with bright punchy colours and sharp detail. The lens gives the standard fisheye perspective, and looking at the footage there are no pronounced signs of detail becoming soft toward the edges, or signs chromatic aberration.
Colours are reproduced well, and tend to lean towards oversaturation. This gives the footage a bright, clean look; there's a slight blue cast in some lighting situations, but it's not something you're likely to notice unless you're looking for it.
Exposure is well controlled in good lighting conditions, and the Session copes well when moving from shade to bright, adjusting the exposure quickly and smoothly.
Shadow and highlight detail is nicely balanced, and while there is some highlight burnout in bright clouds, the tonal gradation between bright areas that contain detail and burnt-out areas is smooth and free of colour casts, so that when the footage is rolling, the burnt-out areas aren't unduly prominent.
The quality of the live view stream via the app is good, although necessarily dependent on the strength of the Wi-Fi signal. In good conditions the stream is smooth, with less than a second's delay between the action happening and it appearing on screen.
In tests we found that the range was limited to around 10 metres, which is perfectly adequate – with action cameras, live view is generally a tool for checking composition, rather than for remote recording.
Although the Session enables you to tag footage as you record, this function seems rather limited compared with the much more user-friendly approach taken by TomTom.
One issue I encountered when using the Session was the length of time between the record button being pressed and the start of recording – this could be in excess of five seconds, and it turned out to be an issue with the MicroSD card.
After a little experimentation with cards from several manufactures, I found that if I stuck with cards from Lexar or SanDisk, as recommended by GoPro, the delay between hitting the shutter button and the start of recording dropped to just over two seconds. It seems that, like the Sony X1000V, the Session is a little picky over the quality of the cards you use.
Even though the Session is 50% smaller than the HERO4 Black, it still manages to compare favourably when it comes to battery life. In our tests, with Wi-Fi switched off and shooting 1080p at 60fps, the camera comfortably captured an hour and a half of video.
Ali Jennings is the imaging lab manager for Future Publishing's Photography portfolio. Using Imatest Master and DxO Analyser he produces the image quality tests for all new cameras and lenses review in TechRadar's cameras channel. Ali has been shooting digital since the early nineties and joined Future's Photography portfolio back in 2003.