Dashcams are advertised almost entirely through one number: resolution. In daily use it decides whether footage is usable far less often than the packaging suggests. It is more useful to pick a camera by the properties that actually count when something happens.
Image quality that holds up
Resolution describes how many pixels there are, not how good they are. Bitrate matters just as much, meaning how much data is stored per second. High resolution footage with a thrifty bitrate falls apart into blocks as soon as anything moves, and that is precisely when a number plate stops being readable.
The second underrated point is field of view. Very wide lenses capture a lot but shrink everything in the centre of the frame. A moderate field of view shows less roadside and more detail where it usually matters.
For darkness, the advertised night vision feature counts for less than the speed of the lens and the size of the sensor. Neither is printed in large type on the box, but both appear in the specifications.
Power and temperature
Behind a windscreen it gets very hot in summer and very cold in winter. Cameras with a capacitor rather than a battery tolerate that considerably better and last longer. Anyone who wants parking mode needs a permanent power supply anyway, usually through hardwiring.
Note
A capacitor stores only enough energy to close the current file cleanly. That is exactly the point: the camera should record while the vehicle supplies power.
Storage and reliability
A dashcam writes without pause. Ordinary memory cards are not built for that and fail after months, often unnoticed. Use a card explicitly rated for continuous write load and check regularly that recording is still happening. There is more on this in the article about memory cards.
Equally important is dependable loop recording with cleanly closed files. Cameras that corrupt the last file when power drops lose exactly the recording that mattered.
What you can safely ignore
Voice assistants, lane keeping warnings and distance alerts built into dashcams are mostly imprecise and tend to distract. A built-in display is a side issue too, if you access recordings through an app or a card reader anyway.
Be careful with very cheap devices from unnamed manufacturers. Missing software updates, unsecured wireless connections and recordings that break off at the decisive moment are a recurring pattern there.
A short checklist
Look for a solid bitrate, a moderate field of view, a capacitor rather than a battery, dependable loop recording, a suitable memory card and regular updates. If those six points hold, the camera suits its purpose, regardless of the number printed on the front of the box.
One camera or two?
For most people a front camera is enough. It covers the situations that are most often disputed. A rear camera pays off mainly if you spend a lot of time in dense traffic, where rear-end collisions and tailgating are part of the routine.
With two-camera systems, make sure both recordings carry the same timestamp. Otherwise two perspectives turn into tedious puzzle work. Which view contributes what is covered in the article on front, rear and interior.
