Auto Zones metering mode (auto-place 3 spots)

Summary

One-tap metering mode that automatically detects and measures the scene's brightest highlight, darkest shadow, and midtone. Uses pixel-precise analysis to place three spots without manual tapping.

How it works

What it does

Switch to Auto Zones mode and tap the preview once. The meter instantly analyzes the scene, finds the brightest important area (a highlight), the darkest important area (a shadow), and the average brightness (midtone), and places three measurement spots automatically. The result is a quick, three-point zone reading without manually tapping three times.

How it finds spots

The app captures a high-resolution preview frame (up to 1024 pixels wide) and analyzes it in 5x5 pixel blocks. The brightest block is marked as the highlight, the darkest as the shadow, and a mid-grey block is marked as midtone. This pixel-level precision avoids false positives like lens flare or accidental reflections.

When to use it

Fast zone system metering. When you want a quick reading of shadow, midtone, and highlight without tapping three times. Or when you are learning the zone system and want the meter to show you where the key brightnesses fall in your scene.

Accuracy notes

Auto Zones works well on scenes with clear tonal separation (a face backlit by a window, a landscape with sun and shadow). On scenes with uniform tone (an overcast day, a white room) the meter may place all three spots in similar brightness ranges, which is accurate but not very useful for zone planning.

Manual refinement

After Auto Zones places the three spots, you can tap on any spot to adjust it, or remove a spot and add a custom one. The multi-spot average recalculates in real time.