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Video options through the camera are accessed by holding down the up navigation button. Options for Movie Size and Video Quality are at the top of the menu which is handy, and below these are a series of other modes , notably Time-Lapse and Motion detection – which starts recording when motion is detected. There are also a few more advanced options that enable you to adjust the white balance and exposure.
Connecting through the app offers far fewer options for adjusting settings but does enable you to quickly start recording remotely and switch to the stills and time-lapse modes.
To make the most of resolutions such as 4K and 720p at 120fps you need to select these options directly through the camera, which is a annoying.
The 4K video is limited to just 10fps but the quality is excellent with a good amount of detail, balanced contrast and good tonal graduation. The lens does suffer from flare when pointed directly into sunlight but generally produces good, clean footage.
• This footage shows a static shot from the Rollei ActionCam 420 taken at full HD 60 fps.
• When the camera is pointed away from the sun to avoid glare the 4K footage looks excellent. However, in this scene you can however see that the camera is burning out highlights in the sky on the left and right of the frame.
• The camera shows fantastic detail and visual quality at 4K, but here we can see signs of flare caused by the case.
• Motion is smooth even at 30 fps as with this footage. However even with the movie quality set to high the image shows signs of pixelation and there is a lack of overall detail.
• Direct comparison between the Rollei Actioncam 420 and the GoPro Hero4 black at 1080p 30fps.
Switching the resolution of the camera to 1080p at 30fps the quality of footage reduces dramatically, with a loss of detail and sudden boost in contrast which is in stark contrast to the quality of the 4K footage. Further reducing the resolution down to 720p drops the quality of the video still further with even more loss of detail.
Initially the Rollei Actioncam 420 looks like a good deal. It looks great and the camera and case are decent enough quality. However, as you dip into the menus and settings it quickly becomes apparent that the full potential of this camera really isn't being realised.
Small design features such as the flat lens on the housing and the simple clearly defined buttons and navigation show that thought has been put into the layout, but there are just too many compromises elsewhere with video quality and the app. If you want a camera that shoots excellent 4k video and you're happy with a frame rate of 10fps, then this camera could be for you. Otherwise are plenty of far better options.
Overall build quality is good and the option to select one of three colours for the camera is a small but welcome feature. The inclusion of a standard tripod thread at the base of the camera is a nice touch as is the large LCD screen. Navigation has been well thought out and finding your way around is exceptionally easy. The 4K video might be limited to just 10fps but the quality is exceptional.
After a muddy ride the lever lock that secures the case closed was near impossible to open and in normal conditions and was fiddly to use. Video quality was the biggest let down and footage shot at 1080p at all frame rates was in stark contrast to the high quality footage shot at 4K. In some ways the slightly larger design did have its advantages when it came to handling the camera, but when the camera is mounted on a board or bike the additional size does mean that the camera is far more likely to be knocked.
If the Full HD 1080p video had matched the quality of the 4K output then the 420 would have been an exception camera. However the high contrast and lack of detail at all but the 4K video settings are a huge disappointment.
The design follows that of the market leading GoPro but the small and seemingly insignificant increase in size does have an effect of where and how the camera can be successfully mounted. When compared side by side with competitors, that additional size really is highlighted.
If you're after a 4K action camera then at present the market is very limited. If you need both quality and frame rate than at present there is still only one option – the GoPro Hero4 Black. Otherwise, at this price point and with similar specifications there's the exception iSAW Edge or at half the price and if you don't mind the older style case you have the SJCAM SJ5000X.
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.