Zone map snapshot logging
Every Log Shot saves a gallery-matte zone map card.
Where to find it
Viewfinder Log Shot button (card written to the shot log gallery)
Summary
Every time you log a shot the app renders a shareable card on a pure black gallery-matte background. The card carries the metered preview with the per-zone color overlay applied, a histogram strip above, the zone ruler below for multi-spot shots, and a summary strip with the exposure triangle, EV, and film stock. A sibling JSON blob stores the raw per-spot luminance for later densitometry.
How it works
What it does
When you tap Log Shot, the app captures the metered frame and renders a gallery-style card. The pure black background and white inner frames make the photo read as a print on a matte. The card pins a 256-bin histogram strip above the photo, the photo itself with numbered spot markers, a Zone System ruler when you measured multiple spots, and a summary strip with aperture, shutter, ISO, EV, focal length, format, and film stock.
Why a card
The card is the durable record of what you metered and how you placed each spot. Months later, when you cross-reference the developed negative against the meter, the card tells you exactly which zone each part of the scene was placed on. That makes it easy to learn from your own shots and tune your personal calibration.
Raw luminance JSON
Alongside the card image the app saves a sibling JSON blob carrying the raw per-spot EV100 readings, the histogram bins, and the analysis result. This is the densitometer-ready data: read the negative on a densitometer, compare to the JSON, and you have ground-truth per-zone density.
Sharing
Cards are JPEG quality 88 and live in the shot log gallery. Tap Share to send one to anyone (text, email, social) without exposing any of the JSON. The card alone is the photo plus the zone reading.
When the snapshot is missing
If the renderer fails (rare: bitmap decode error, no preview captured, IO failure on the storage path) the shot is still logged but without the card image. The exposure summary and EV log entry remain intact.