How to film a car detailing video with both iPhone cameras

Getting close to a defect means picking the lens yourself

Swirl marks, water spots and the fine scratches a correction is meant to remove only read on camera from close up, and a multi-camera session does not have the automatic macro switch the stock Camera app uses to handle that: on a single-camera session, getting close to something makes the system quietly hand the frame to the ultra-wide lens, which focuses much closer than the main lens. Simultaneous front-and-back recording connects to one specific physical lens per camera instead of a virtual device that can make that swap on your behalf, so that hand-off simply is not available here.

The fix is the same one that applies to any close shot on the back camera: pick ultra wide yourself from the lens picker, if your iPhone has one, before you move in on the panel. Which back lens is active locks in for the whole take the same way resolution does, so a wide establishing shot of the whole panel and a close pass over one specific defect are two separate takes with two separate lens choices, not one continuous zoom.

Picture-in-picture and top-and-bottom survive a moving hand better than a crop

The back camera filling the frame with the panel or seat, your face and commentary riding in a picture-in-picture window, is the natural default here for the same reason it works for any product demonstration — the surface being worked on is the thing the viewer needs to actually see. DualCam lets that window sit in any of the four corners at three sizes, so it can be placed somewhere it is not covering the exact spot a microfiber towel or a polisher pad is passing over.

If you would rather split the screen, top-and-bottom keeps the full width of both frames, which matters more here than it might look: a hand working a panel with a towel or a pad drifts left and right across it constantly, not just once like a person stepping into frame. A left-and-right split crops roughly a quarter off each side of a vertical canvas to fit it, and that missing quarter is exactly where a reaching hand spends a good part of its time.

The filter has to stay the same across a before and an after

DualCam’s six live filters are applied in the shader as the frame is recorded, not layered on afterward, which means a filter genuinely changes the color and contrast that ends up in the file. Recording the “before” pass with no filter and the “after” pass on Vivid does not just look different — it makes a real correction look more dramatic than it was, or hides a mediocre one, because part of what the viewer is reacting to is the filter and not the paint. Pick one filter, or none, before the job starts and leave it there for every pass you intend to compare.

The other half of a fair reveal is exposure, and that still has to be set per pass rather than assumed. Seeing a swirl mark at all usually needs raking light across the panel, and that same light can blow out the clearcoat’s highlights if the camera is metering the sky behind it instead of the paint — tap the panel to expose for it. The front and back cameras still meter independently of each other, so getting the panel right does not automatically get your face right too; tap whichever frame actually needs the help.

One microphone hears the polisher or the pressure washer as clearly as it hears you

A dual recording writes a single mono audio track from whatever iOS has set as the default input, not one channel per camera and nothing that can isolate your voice from a tool running next to it. A random orbital polisher, a shop vac or a pressure washer at close range is genuinely loud, and it lands in that one track at whatever level it actually produces, right alongside your narration — there is no separate take of just your voice to fall back on once the file is finished.

The practical fix is timing rather than volume, since there is no gain control to reach for. Say the product name or the step you are about to show before the loudest tool starts, let it run under the visual once it does, and pick narration back up in the gap after it stops.

• Finish the sentence that matters before switching the polisher or the vacuum on — there is no clean way to lift a line out from under tool noise afterward.
• A pressure washer held close to the phone can push loud enough to clip rather than just sound loud; see the guide on distorted or crackly audio in loud places for what that is and what actually helps.
• Treat quiet stretches — between passes, while a product dwells on a surface — as your narration windows, rather than trying to talk over the tool the whole time.

Wash, correction and interior are already separate takes — treat them that way

A dual-camera recording runs straight through from record to stop with no way to pause it, so a job that naturally has a wash stage, a correction or wax stage and an interior stage was never going to be one unbroken recording anyway. Stopping and starting a fresh take for each stage costs nothing — each one already has a different distance, a different light and often a different location, in the sun for the exterior and in the shade of the garage for the interior — and a normal video editor joins the finished clips afterward the same way it joins any others.

Splitting the job up this way also buys real thermal headroom on the stage that needs it most. Full sun on a driveway adds real heat to the phone on top of what two live camera feeds and a GPU composite already generate, and that combination — not storage — is usually what actually ends a long exterior pass. Shoot the wash and correction stages as their own shorter takes with a minute of shade for the phone between them, rather than holding one recording from the first rinse to the final walkaround.