YsEVMeter
Spot light meter & Zone System
Only for iPhone
$2.99 · Designed for iPhone. Not verified for macOS.
iPhone
See your scene in zones. Meter highlights, midtones, and shadows in EV, then place every tone exactly where you want it on film. The Zone System, in your pocket.
YsEVMeter turns your iPhone into a precise three-zone spot light meter for photographers who care about exposure. Point the camera at your scene and read highlight, midtone, and shadow values in real time — then work the way film photographers always have, with the Ansel Adams Zone System built in.
METER THE SCENE
• Real-time EV metering straight from the live camera
• Three-zone spot metering: highlight (red), midtone (green), shadow (blue)
• Drag any spot to re-meter, or tap to drop your own custom spots
• ISO from 25 to 102400, in color or black & white
SEE THE LIGHT
• Zone Map overlay posterizes your scene into the 11 Ansel Adams zones (0–X)
• Heatmap overlay reveals luminance across the whole frame
• Histogram overlay with shadow, midtone, and highlight markers
• Adaptive zone detection: 2% percentile, Otsu auto-thresholding, or manual sliders
CALCULATE THE EXPOSURE
Freeze a snapshot or load a photo from your library (with its EXIF aperture, shutter, and ISO), then solve the exposure:
• Aperture f/1–f/64, shutter 1/8000s–480s, EV adjustment ±5 stops
• Full-stop or 1/3-stop increments
• Color (Wratten) and ND filter compensation
• Bellows-extension compensation for large-format work
• Reciprocity-failure correction with film-stock presets for long exposures
• Smart linking keeps aperture and shutter balanced as you adjust
DIAL IT IN
• Calibrate against a reference meter for readings you can trust
• Frame the shot — preview the exact crop for 35mm, 6×6, 4×5, or a custom format at any focal length, in portrait or landscape
• Record exposures to film rolls or quick memos, with optional GPS tagging
PRIVATE BY DESIGN
Everything runs entirely on your device. No account, no ads, no tracking — your photos and data never leave your iPhone.
Made for film shooters, large-format photographers, and anyone learning to see in zones.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, Midtone Lab LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Midtone Lab LLC
- Size
- 7.2 MB
- Category
- Photo & Video
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Age Rating
4+
- 4+
- Copyright
- © 2026 Midtone Lab LLC
