Straighten leaning walls in interior photos.

Correction always costs you frame

Straightening converging verticals means rotating the image plane, which leaves empty wedges at the edges that have to be cropped away. The more severe the tilt, the more of the room disappears in the correction. A photo shot with the camera angled sharply upward to fit the ceiling can lose fifteen per cent of its width once it is squared up, and what goes first is the outer edge of the frame — often the wardrobe, the doorway, or the corner that established the room's size.

This is the argument for holding the camera level at the point of capture rather than relying on correction. A level camera at chest height produces a file that needs almost no geometric work and keeps everything that was in the viewfinder.

Straight lines are what read as professional

Most people cannot say why an amateur interior photo looks amateur, but the answer is usually geometry rather than exposure. Door frames that lean, skirting boards that curve, and worktops that tilt are read instantly as a snapshot, even when the lighting is good. Conversely a modestly lit room with perfectly vertical lines reads as considered.

The limit is that correction restores the geometry the scene actually had. It cannot widen a room, extend a wall, or change the apparent floor area, and a correction pushed far enough to attempt that starts producing visibly stretched furniture at the frame edges.

• Hold the camera level rather than tilting up to include the ceiling
• Shoot at about chest height for most interior rooms
• Back into a corner rather than standing in the middle of the room
• Use the phone's built-in level indicator if it has one