Single-Channel Dash Cams
For convertibles, front-only dash cams are more common. Covering the front view is highly crucial as it records everything happening ahead of you. However, if you're looking to incorporate a secondary camera, you can go with a rear camera and mount it on your windshield the way you mount your IR camera.
Small and Screenless Dash Cams
In terms of size, a huge dash cam may not be the ideal choice for you. If you have a dash cam with an LCD screen for example, it will be a sparkling invitation to car thieves especially when your car is open. If you park in a shady area, there is nothing stopping someone from snatching your dash cam off your windshield and running away. So here, better get a BlackVue or a Thinkware.
IR Dash Cams
With the top off, we also recommend utilizing a front dash cam with an IR dash cam. A front dash cam and a cabin camera are standard configurations in ride-hailing vehicles. While the cabin camera is meant to capture only the car's interiors and passengers, the story is different in a convertible as the camera will capture everything outside the car as well.
Front and rear, maybe?
Again, we are not restricting you from getting a front and rear dash cam. You still can. Just consider that in most cases, the back seat of the convertible is fairly thin between the two rear headrests, so any mount is sure to come flying off when you get up to speed.
If you decide to go for a dual channel setup, then try to find a small, rear camera that can be mounted in your license plate, just like a normal backup camera would. Also, make sure the rear connecting cable can be tucked in a spot that will remain stationary even if you take the top down.