Dash Cams: Front, Rear and Three-Channel Compared

Everything else on the spec sheet is a refinement. This is the choice that determines whether the footage is useful.

Single channel

One camera, forward facing. It records the road ahead, which is the most common single point of contact in a crash. It is the cheapest category and it is adequate for basic insurance evidence.

The limitation is obvious in hindsight. In a rear-end collision the front camera records an entirely ordinary drive. In a side impact it records very little. If your vehicle has anything mounted at the rear — a bike rack, a tow bar, a load — a front-only camera cannot see it at all.

Dual channel: front and rear

Two cameras, one recording forward and one rearward. This is the configuration most people should buy, because it covers both the most common crash types and most of what you actually need as evidence.

A dual lens dash cam recording front, rear and cabin at 1080p is the standard shape of this category and sits at the affordable end. The adds resolution on the forward channel, which is where it is most useful.

Triple channel

Front, rear and inside the cabin. The third camera watches the cabin, which means it captures the driver as well as the road.

This matters in two situations specifically. Insurance disputes where a driver is accused of distraction, and any incident involving a passenger. It is also the configuration most likely to raise a privacy consideration with anyone else in the vehicle, which is worth thinking about before you fit one.

The is the typical product. Note that a three-channel camera is writing three times as much data, which is why the memory card decision becomes much less optional.

Four-channel and 360-degree models

A handful of units add a fourth camera or a stitched 360-degree view. The stitched version removes the blind spots that single forward-facing cameras have, but it produces fisheye distortion at the edges and needs careful mounting to avoid an unusable seam. The is the product to look at if you park in genuinely risky places.

The resolution figure is the number every listing leads with and the one that matters least. Above roughly 1080p you are adding pixels you rarely need, because the limit becomes how the camera handles the scene rather than how many samples it takes.

What determines whether you can use the footage is contrast and dynamic range. A camera that copes well with a bright sky and a dark car park will give you a readable number plate; a higher-resolution camera that blows out the highlights or turns night footage to grey mush will not.

A good comparison point is the , where the screen is the point — it gives you immediate playback and a live view for parking, which some drivers find more useful than extra resolution. At the top of the range, a adds phone connectivity so you can pull footage without touching the card.

One thing genuinely worth paying for: a circular polarising filter reduces the glare reflection off windscreens and bonnet paint, which is the single most common reason a number plate is unreadable in daytime footage. A is inexpensive and makes a visible difference in bright sun.

A dash cam writes continuously for hours at a time. This is a workload standard cards are not designed for, and a standard card will eventually fail — leaving you with either no file or a corrupt one exactly when you need it.

Three rules.

• Buy an endurance-rated card. They are designed for continuous write and high-temperature conditions, both of which a dash cam creates. A is the correct type of product.
• Check the capacity is genuinely supported. Cards advertise far more than any camera can use, and a card the camera cannot fully use can behave unreliably at the end of its range.
• Format the card in the camera itself. The camera's own formatting option writes the file structure the firmware expects. A card formatted on a computer can work for weeks and then produce recording failures.

Replace the card every year or two regardless of how it looks. Endurance cards do not fail gradually — they fail suddenly.

The supplied mount is often the weakest part of the whole setup, and it is the part that determines whether your footage is legible.

• Position. High enough on the windscreen to clear the bonnet and wipers, and to the side of the driver's sightline so it does not obstruct it. Wipers are the single most common thing to smear across a plate.
• Rigid mounting. Suction mounts that let the camera move in a collision can leave the footage shaking too badly to read the plate. Adhesive mounts are stiffer.
• Power. Hardwire kits give you constant power and no cable across the cabin, but you need to know your vehicle's fuse layout and choose a fuse that is not a safety-critical circuit.
• Check the rear mount separately. Rear cameras are usually attached to the glass, which can be close to a demister grid or a heating element. If the glass there is heated, image quality suffers.

If your car already has a rear camera or a factory recorder, a is a cheap way to position an aftermarket camera where the factory one sits.

Motorcycle cameras

A bike camera is a different product with different requirements — weight, weather sealing and a genuinely waterproof body rather than a splash-resistant one. A is the shape of product that works, and the reasons to fit one are the same as for a car.

Simple front-and-rear units

If you want the insurance evidence and nothing else, a is the cheapest complete setup, and there is no reason to pay more unless you need the resolution or the screen.

Plain dual-lens units

The simplest and most commonly recommended configuration is a . It is not the most sophisticated option, but it solves the problem the majority of people are actually buying a dash cam to solve, and it is the least likely to be a disappointing purchase.

Worth knowing because it changes how you should set the camera up. Dash cam footage is stored on a card that overwrites itself, oldest first. If you do not copy the clip off promptly, a collision a week ago may already be gone.

That makes automatic saving the most valuable feature on any model. WiFi-connected cameras that back up to your phone when you connect are worth a premium over otherwise identical units for exactly this reason, because relying on remembering to do it manually means it will not happen.

Also check whether your jurisdiction requires you to provide footage to an insurer within a specific window, because a card that overwrites itself is in tension with an obligation to keep it.

Buying a standard memory card. The most common failure in the category, and it fails at the worst possible moment.

Mounting too low. The bonnet or the dashboard fills the bottom of the frame and the road ahead is compressed.

Mounting behind the wiper arc. The most common reason a plate is unreadable in rain.

Buying 4K and expecting a better picture. You get a bigger file and a card that fills faster. Exposure matters more.

Forgetting to check the date and time. Footage with an incorrect timestamp is much weaker evidence. Set it from GPS rather than setting it by hand.

Not testing it. Play back a clip before you need it. A camera that has been recording corrupt files for a month is worse than no camera, because you rely on it.

A dual-channel front-and-rear camera with a proper memory card, mounted high and to the side with the lens clear of the wiper arc. Add a polarising filter if you drive in bright sun. That combination costs less than most people expect and covers the overwhelming majority of what a dash cam needs to do.

Only step up to three channels if you need cabin coverage for a specific reason, and to 4K if you genuinely need to read fine detail in footage. Neither is the first thing to prioritise.

If you drive a lot at night, prioritise a camera with good low-light handling over resolution, and test it after dark on a familiar route before you rely on it.

Our winter car emergency kit guide covers the other equipment that is worth carrying, and our phone mount guide covers the positioning problem for your phone, which is the same judgement you make with a dash cam.

eBay prices move daily and condition varies a lot between sellers, so check recent sold listings before committing rather than trusting the first price you see.