# YsEVMeter — Spot light meter & Zone System

> Spot light meter & Zone System (iPhone/iPad app by Midtone Lab LLC.)

- Source: https://appshunter.io/ios/app/ysevmeter/id6773098117 (this page in markdown: same URL + `.md`)
- Developer: [Midtone Lab LLC](https://appshunter.io/developer/6773098119)
- Category: Photo & Video, Productivity
- Price: $2.99
- Age rating: 4+
- Requires: iOS 17.0 · 7 MB
- Released: 2026-06-02
- Data updated: 2026-06-03
- User reviews in markdown: https://appshunter.io/ios/app/ysevmeter/id6773098117/reviews.md

## What is YsEVMeter?

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.


## Version history (last 1 release)

### 1.0 — 2026-06-02

No release notes.

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-03.*