What it means to shoot log on an iPhone

What is log video, and why do my clips look flat and gray?

Log is a way to record video that keeps more highlight and shadow detail than a standard picture profile. The price is a flat, low-contrast, gray picture straight from the camera. The flatness is the point, not a fault, because you restore the contrast later in a step called grading. Log Cam: RAW 4K Video Camera is an iPhone app that records log video in any of seven log profiles.

Log protects dynamic range. Dynamic range is the distance between the brightest and the darkest part of a scene the camera can see. Real scenes often exceed what a standard profile keeps: a face against a window, a street at dusk, any shot with sky. A standard profile decides how to handle that range at the moment you record. What it discards is discarded for good. A log profile records a wider slice of the range and leaves the decision to you.

This is why the first log clip is a disappointment. You expected a better picture, and you got a washed-out gray version of the scene. Nothing went wrong. You look at a clip that is not developed yet, in about the same sense as a film negative.

Grading is that development step, and it happens in your editing app, not in the camera. You restore the contrast, set where black sits, and move the color where you want it. Most editing apps also offer a conversion that gives you a normal picture in one move. Apply that conversion first, then adjust. The extra range you shot for is what makes the adjustment hold. You can darken a bright window or lift a shadow and still find detail.

More than one log curve exists, because manufacturers made different decisions about how to spend the range. That is why this app offers Apple Log, Apple Log 2, S-Log3, Log-C3, V-Log, F-Log and F-Log2. The conversion you apply in the edit is built for one specific curve. So shoot the curve your workflow expects, and you do not approximate it later. At the start, Apple Log is a good default and the choice can wait.

It is worth a blunt statement about when log is not worth it. Log is worth it if you will edit the clip, or if you bake a LUT into the recording. If you do neither, and you post a clip the way it leaves the phone, a standard profile looks better with no work. That choice is not a compromise. Log is for the video you intend to spend time on.

If you tried log once, got a gray clip and stopped, try it again here. Switch the viewfinder to Look and the screen shows a normal picture while the recording stays log. Import your own .cube LUT and you can watch a graded picture instead. You can also write that LUT into the clip, and then you shoot a finished picture rather than one to grade. That last choice cannot be undone, so keep it for the clips you do not intend to edit. And when a flat picture is no longer confusing, the tools under it are still enough.