Doubleback Case Study | Sheldon Charron

2 min

Of pre-roll. In standby Doubleback is already filming, so a late press still catches what just happened, on both cameras, at up to 4K120

2 minOf pre-roll. Even in standby the app is filming, so the take starts before anyone presses record

2 anglesThe rear and front cameras record at the same time, up to 4K120 on both, and both files stay untouched

1stDual-camera app ready for the iPhone 18 and the iPhone Duo, built and tested before either reached a store

The problem

In news, documentary and sport, you don’t get a second take. Someone breaks out of the crowd on the courthouse steps. The winning goal goes in. A protest turns. By the time anyone presses record it’s over, and in news you can’t stage it again. Reporters, documentary photographers and cinematographers, freelancers and creators all live with the same gap: the moment that matters happens before the camera is rolling.

And they want two things in that shot: the scene, and their own face as it happens. A phone camera gives them one or the other.

Where it came from

The answer was already working in a hunting app. I built PREYR’s pro video for hunters, who miss the shot the same way: KILLSHOT keeps two minutes of pre-roll, and 2SHOT films both cameras at once. The tools turned out to be bigger than hunting. I took them out of PREYR and rebuilt them as Doubleback, a camera of their own, for anyone who films the news, a campaign, or their own business. The PREYR story.

What it does

The take starts before you press record. Leave Doubleback in standby, pointed at the scene, and it keeps a rolling buffer of up to two minutes of picture and sound. When something happens, press record and start talking. The buffer goes on the front of the clip, so the take has everything that led up to the moment. One seamless clip, from before and after the press.

Dual: both cameras, two clean files. Turn on Dual and the rear and front cameras record together, up to 4K120 on both. The 2-shot, with the reporter in the corner or in a split, is ready to post the moment the take stops, and both original files are kept untouched for the editor.

What no other app does. Plenty of apps film both cameras at once. None I have found also keep up to two minutes of pre-roll, at up to 4K120, with both original files kept.

Change the layout after the take. Which camera fills the frame, the corner, the size and the shape of the inset can all change after filming. Doubleback remakes the 2-shot from the two originals, as often as needed. No reshoot.

Your logo on every clip. A station, a candidate, or a business puts its own logo or handle where the Doubleback watermark would go.

Doubleback in standby at a youth soccer game, with two minutes of pre-roll on — **Pre-roll**Standby at the game, 2m on. Press record when the goal goes in and the clip starts before it.

**Pre-roll**Standby at the game, 2m on. Press record when the goal goes in and the clip starts before it.

The Take screen: the rear file, the front file, and the 2-shot ready to post — **The take**The rear original, the front original, and the 2-shot ready to post. Change the layout any time.

**The take**The rear original, the front original, and the 2-shot ready to post. Change the layout any time.

**Dual on scene**The press conference and the reporter in one take, with the station's logo on the frame.

Who it is for

Reporters and newsrooms. Stand-ups and on-scene reports that look like the station, filmed on a phone.

Campaigns. Every volunteer’s video carries the candidate’s colors.

Local businesses. Pool companies, contractors, realtors: walk the job, talk to camera, post it with the logo.

The same pre-roll is why it works chest-mounted in a harness for security and law enforcement work, where the moment that matters has usually passed before anyone thinks to record.

Ready for the iPhone Duo before it reached a store

The iPhone Duo opens into a screen no iPhone has had, nearly square, and video is not. An ordinary app sits in a phone-shaped box with black beside it. So before the Duo reached a store, I worked out what a camera should do with that screen:

Fill it edge to edge and put the controls in the leftover strip, never over the picture.
A FULL format that records from the whole sensor, so the unfolded screen is the shot.
Half open on a table, the standing half is the picture and the flat half is a big clock, a zoom and a record button. No tripod.
The tent, a two-sided interview from one phone, each person on their own camera. Still on the drawing board.

The first sketch of Doubleback on the open iPhone Duo, drawn on October 7, shown on the Duo — **The sketch, and the app.** The first drawing of Doubleback on the open Duo, and the shipped app held the same way.

Doubleback on the open iPhone Duo, held as it opens: the tall picture in the middle of the screen with the reporter inset from the front camera, the clock and level meters on the left, the zoom and record controls on the right — **The sketch, and the app.** The first drawing of Doubleback on the open Duo, and the shipped app held the same way.

Doubleback on the closed iPhone Duo held upright: the picture full height with the controls in a column beside it — **Every way the Duo is held.** Closed upright, closed held wide, open as it opens, open turned. The picture fills the screen edge to edge and the controls sit in the leftover strip, never over it.

Doubleback on the closed iPhone Duo held wide: readouts above the picture, buttons below — **Every way the Duo is held.** Closed upright, closed held wide, open as it opens, open turned. The picture fills the screen edge to edge and the controls sit in the leftover strip, never over it.

Sketch: the Duo half open on a table seen from the side, the standing half is the picture and the flat half is the controls — **Half open on a table.** The standing half is the picture and the flat half is a big clock, a zoom and a record button. No tripod.

Sketch: the screen half open, the picture on top and a big clock, zoom and record button on the flat half — **Half open on a table.** The standing half is the picture and the flat half is a big clock, a zoom and a record button. No tripod.

Sketch: the Duo stood like a tent between two people, the outside screen and selfie camera facing one, the rear cameras filming the other — **The tent.** A two-sided interview from one phone, each person on their own camera. Still on the drawing board.

Sketch: the outside screen in tent mode, the guest filling the frame and the interviewer inset — **The tent.** A two-sided interview from one phone, each person on their own camera. Still on the drawing board.

The layouts and the FULL format were built and tested on Apple’s simulator and approved by the App Store before the first pre-orders opened. The same release wires in the iPhone 18’s lens and camera controls, so a take can start and stop from the hardware without touching the screen.

The whole design story, sketch by sketch, is on the Doubleback site: see how the Duo layouts were designed.

The business model

Free to download, with everything on from the first take. No account, no trial that runs out, and no upload: clips stay on the phone until they are shared. Shared clips carry a small Doubleback watermark, and two one-time upgrades pay for the app:

FreeEvery feature, with a small Doubleback watermark on shared clips
$4.99 onceClips go out clean. No subscription
$9.99 onceYour own logo or handle in place of the watermark

How I built it

I did the product strategy, design, software and launch, directing a team of AI agents to speed the build. It runs on iPhone 15 Pro and later, on purpose. The newest cameras and chips are what make two cameras with a two-minute pre-roll possible.

Get Doubleback

doublebackcam.com