Hi everyone,
I am new here, and just started the process of researching my dashcam purchase. From my brief research, it seems that most dashcams currently on the market are not capable of reliably capturing US license plates when traveling at highway speeds, even during the day.
1080p simply isn't enough resolution when we're talking about a 140°+ field of view to render a readable license plate, unless it's very close and straight ahead. The 4k DR900S is better, but its resolving power is compromised by its extremely wide 162° FOV, so it's not measurably better than the 1440p Viofo cameras. Additionally, the bitrate on most dashcam models is far too low, and still frames turn into mush. I do understand that dashcams have limited processing power, so compression settings have to be tweaked for speed over quality, but this problem can be fixed by increasing the bitrate. While 100Mbps will drastically cut recording time, it will greatly increase the odds of identifying a license plate in the footage. This is not for everyone, but it seems that it should at least be an option, instead of the 25Mbps that the high end cameras top out at.
Finally, in reviews, few people discuss dynamic range of sensors, and I can't find anyone who has actually measured them at all. Most people talk about the "brightness" of footage, and use this as a metric to compare different cameras, but brighter footage does not mean that the quality is better. The only metrics that matter for forensics are resolution and dynamic range (signal-to-noise ratio). Furthermore, darker footage is often better than brighter footage, given the reflective nature of license plates. Once an area is blown out, no details can be recovered.
I have a two-part question:
- Is it actually important in most cases to be able to capture a license plate? It matters for hit-and-runs, but how common are those events compared to "normal" incidents when dashcam footage is used help arbitrate a he said, she said situation?
- If it actually is important, what is the best resolving dashcam currently on the market for both day and night recording, after tweaking with custom firmware?