Scene. Guide. Score.

Several times a second, Camera Grid looks at the frame with Apple’s Vision framework, on your iPhone. It is not judging whether a picture is pretty. It is reading the facts a composition is built on.

• The subject: what stands out, where it sits and how much of the frame it fills.
• People: faces, which way they turn, and where the eyes are.
• Objects: how many there are, and whether you look down on them or across.
• The horizon: where it runs and whether it is level.
• Lines and symmetry: vanishing points, a mirrored facade, a reflection in water, a curve.
• Your hands: how the phone is tilted and angled, from its motion sensors.

When it cannot read something, it scores lower rather than guess. A missing signal never makes a score look better than it is.

The reading comes first, then the guide. A portrait gets Half-Body, a plate seen from above gets Aerial, a corridor gets One-Point Perspective. Auto chooses among the guides made for that kind of scene and draws the one that fits as a target.

Then it holds still. A guide stays on screen for at least two seconds, and it changes only when the scene needs a different kind of guide: a person steps in, you add or take away an object, a table comes into view. A reading that wobbles never swaps it.

• Auto: Camera Grid chooses, and keeps choosing as the scene changes.
• Hold: tap any guide in the strip above the shutter, or Use this guide in the library. It stays until you tap it again or tap Auto.
• A held guide the scene cannot support shows no score, rather than a number it cannot back up.

The ring around the shutter is the fit score: how close your framing is to the guide, measured on every frame. It fills as you get closer.

Above it, the coach gives one instruction at a time, the single change that matters most right now, in plain words. Once you are locked it goes quiet.

• Yellow: close.
• Green: locked, with a tap in your hand.
• No number: the scene gives this guide nothing to measure.