Timetracks4D

Timetracks4D is a camera that cuts time out as if it were space.

Think of video as a cube stacked in three directions: width, height and time. Ordinary playback cuts that cube straight across time and shows you the slices one after another. Timetracks4D tilts the cut. Once it is tilted, every place on the screen shows a different moment: whatever held still comes out as it was, and only what moved is twisted.

■ Two ways to shoot

[Movie] Records while the cut turns. The tilt changes from frame to frame, so the picture keeps moving. Angle, Speed and Window Time change how it twists.

[Still] Builds one picture by stacking narrow bands, one at a time. Each band was taken at a different moment, so the finished picture reads as the flow of time from top to bottom. This is the slit scan, the way the first Timetracks worked. It saves a long picture: eight screenfuls joined end to end, each at the camera's own resolution.

Both are made from the same camera feed, but they treat time differently, so each one has its own settings.

■ Main settings

• Camera (Back / Front), Zoom (Lens), Resolution, Frame Rate
• Transform (Shear / Rotate) and the edge time runs along (Long Edge / Short Edge)
• Auto Rotate speed, Angle, Window Time
• How the band moves (One-way / Palindrome / Wave / Fixed / Drift / Random)
• Interval between bands, from single frames to hours
• Scan Width
• Full Screen, Show Buttons, Touch Gestures, Prevent Auto-Lock
• Add Location

There is a button that randomizes the settings. If you are not sure what to touch first, press that.

■ Getting a good result

Hold the device still. If the device moves, the whole picture moves with it and you cannot tell that apart from the subject moving. A tripod or a table is the sure way.

Point it at something that moves. A still subject seen from a still device gives the same picture at every moment, so nothing happens. People walking, a hand, water, traffic, anything swaying in the wind - these work well.

Once you have the feel of it, try moving the device instead. That is where the more complicated shapes come from.

■ Pricing

Everything except recording is free. Play with the camera and the settings as much as you like; the picture you would get is on the screen already. Try it first.

Full Access (a one-time in-app purchase) removes the ad and lets you save movies and stills.

If you have already bought Timetracks, you do not need to buy anything. Full Access turns on by itself when you update.