Exposure is the average brightness of the frame. Lost detail is how much of it has gone to pure white or pure black — those pixels hold nothing you can recover later, however you edit. Sharpness is how much definition the edges have. Colour cast is how far the overall colour balance sits from neutral, and which way it leans. Even lighting compares the four quadrants and tells you if one is sitting in shadow.
ShotCheck measures the frame, not your intention. A low-key shot is genuinely dark, and the app says so. Read the finding, and ignore it when the darkness is the point.
Sharpness is measured across the whole frame. A portrait with a deliberately blurred background will measure softer than the same subject against a flat wall. It is telling you about the image as a whole, not about your focus point.
Correctly — a sunset really is far from neutral. The measurement describes the light; whether that is a problem is your call.
No. ShotCheck only reads. It does not edit, crop, save, copy or upload anything, and it never writes to your photo library.
Measurements run at up to 900 pixels on the long edge. The values are averages and edge energy, which do not change meaningfully at higher resolution, so larger photos are scaled down first to keep the check instant.
The ad-free unlock is a one-time purchase tied to your Apple ID. On a new device, open Premium and tap Restore purchase.