BlackVue just introduced HDR Night Vision, a new feature for DR900S series dashcams. The feature replaces Enhanced Night Vision and improves both day and night video quality.
You can find it under Firmware settings > Basic > Video > HDR Night Vision (On (Always) | On (Parking mode only) | Off). Don’t forget to hit “Save and close” to apply the changes.
Important: HDR Night Vision applies to 4K sensors only. For dual-channel models like DR900S-2CH, turning HDR Night Vision on will apply it to the front camera, while the rear camera will use Night Vision.
This feature was added with firmware version 1.012 for DR900S Series.
Brightness at night does not always mean clarity
Before HDR Night Vision, DR900S Series front cameras were using Enhanced Night Vision, which boosts ISO gain in dark environments, resulting in brighter images. Although a certain level of brightness is definitely required to distinguish details at night, brightness alone is not always enough.
To keep videos bright in dark scenes, dashcam image sensors increase their ISO sensitivity. This affects the whole image, not just the dark areas. This means if something was already bright—like a license plate—it can get totally blown out. In fact, with vehicle headlights on, license plates at night often appear too bright, almost pure white, therefore unreadable.
How to avoid this?
HDR to the rescue
The human eye can process highly contrasted images rather easily. A digital image sensor, however, is limited in the ratio between the darkest and the brightest point it can capture.
With most digital cameras, whether you capture a photo or a video, the camera adjusts exposure based on your point of focus. On your phone, if you focus on a bright element, the camera will adjust and make everything else in the frame appear darker. Conversely, if you focus on a dark point, highlights may appear blown out. Although sensors have become better at capturing highly contrasted scenes, they still don’t come close to the human eye. High Dynamic Range (HDR) is a way to overcome this limitation of digital sensors.
HDR Night Vision applies HDR to video capture
One of the main advantages of HDR is to preserve detail in both bright and dark areas of the image. You probably have experienced HDR capture with your mobile phone’s camera. It works by combining two or more exposures in a single image. It is like taking an overexposed image (too bright) and an underexposed image (too dark) and combining them together. Except that your camera does it all in one smooth sequence. The overexposed image will show more detail in the dark areas, while the underexposed image will preserve detail in highlights. By merging them, the resulting image is able to display a wider range of colors and detail than the camera sensor was able to capture in a single exposure.
HDR Night Vision follows the same process, applied to video recording.
Better nighttime and daytime video
The advantage of HDR Night Vision over Night Vision is that it improves not only nighttime videos but also daytime recording. At night, it brightens scenes while preserving highlights, which means you can read the license plates of cars and streetlights’ flare is reduced. On bright days, it also works wonders to minimize lens flare and reflections when facing the sun.
HDR Night Vision also produces richer and more accurate colors day and night.
What’s the catch? Should you use it?
You might ask “If it is so great, why even give the choice to deactivate HDR Night Vision?”.
For each recorded frame, HDR Night Vision combines two images in one, with various exposures. At night, it can cause a visual artifact in fast-moving bright objects which may be visible when pausing the video. However, the advantages outweigh the cons in most situations. It’s just something to keep in mind, and you are free to deactivate the feature if you prefer without. If you are interested in using HDR but think the rear camera would be too bright with Night Vision, you can adjust the brightness of the rear cam independently.