ExposureCompensation Manual

GeoLog Feature Documentation

Overview

GeoLog’s exposure calculator helps you figure out camera settings for long exposures, especially when using ND filters or shooting film. The integrated timer counts down long exposures with notifications and Live Activity support.

Exposure Calculator

Basic Use

  1. Tap Exposure Calculator from menu
  2. Set your base exposure:
  • Tap Aperture to adjust f-stop
  • Tap Shutter to adjust speed
  • Tap ISO to set sensitivity
  1. View calculated results

Adding Filters

Taking a long exposure with ND filters?

  1. Tap Add Filter
  2. Choose type:
  • ND Filter – Select strength (ND2, ND8, ND64, etc.)
  • Polarizer – Usually 1-2 stops
  • Custom – Enter any stop value
  1. Calculator shows your new shutter speed

Stack multiple filters:

  • Add as many as you need
  • GeoLog calculates total compensation
  • Remove filters by tapping the × button

Example

Base exposure: f/11, 1/60s, ISO 100
Add filter: ND1000 (10 stops)
Result: f/11, 16s, ISO 100

Now swipe to the timer page and start the countdown.

Film Reciprocity

Film behaves differently during long exposures (reciprocity failure). GeoLog automatically corrects for this.

Using Reciprocity

  1. In exposure calculator, select your film stock from dropdown
  2. As shutter speed increases, GeoLog applies correction
  3. Final result shows actual exposure time needed

Supported films:

  • Kodak (Ektar, Portra, T-Max, Tri-X)
  • Fuji (Velvia, Provia, Acros)
  • Ilford (HP5, FP4, Delta)
  • Many more

Example with Film

Setup: Kodak Ektar, f/8, 8s base exposure
Reciprocity applied: Corrected to 11s actual exposure
Why: Film needs extra time at long exposures

Exposure Timer

For exposures longer than 1 second, use the timer for precise countdown.

Starting the Timer

  1. Calculate your exposure
  2. Swipe left to timer page
  3. Tap Start Timer
  4. Timer begins countdown

Or enter a custom time directly in the timer field.

Timer Modes

Sound Mode 🔊

  • Last 11 seconds: Audio countdown (“10… 9… 8…”)
  • Completion tone
  • Great for outdoor shooting

Silent Mode 🔕

  • Haptic vibration pulses
  • No audio disturbance
  • Perfect for quiet environments

Tap the sound/silent icon to switch modes while timer is running.

Live Activity Features

Dynamic Island (iPhone 14 Pro+)

The timer appears as a Live Activity:

  • Shows time remaining
  • Always visible while timer runs
  • Tap to return to timer page
  • Works even when app is in background

Lock Screen

Timer widget appears on your lock screen:

  • See countdown without unlocking
  • Tap to open GeoLog
  • Works with Always-On Display

Background Operation

The timer keeps running when you:

  • Lock your phone
  • Switch to another app
  • Take phone calls
  • Use other apps

Battery note: Live Activities use some battery. For very long exposures (>30 minutes), consider that battery drain.

Timer Notifications

GeoLog sends smart notifications during long exposures:

  • 10 minutes remaining – For exposures over 10 minutes
  • 2 minutes remaining – Get ready to finish
  • Timer complete – Close your shutter now

Set up notifications:
iOS Settings → Notifications → GeoLog → Enable “Time Sensitive Notifications”

How the Timer Works

Starting an Exposure

  1. Calculate your exposure (or enter time manually)
  2. Start the timer
  3. Open your camera’s shutter (bulb mode)
  4. Wait for timer to complete
  5. Close your camera’s shutter when timer finishes

Timer Controls

  • Start – Begin countdown
  • Stop – Cancel timer
  • Reset – Return to original duration

The timer automatically switches to background mode when you lock your phone or switch apps.

Practical Workflows

Long Exposure Landscape

  1. Calculate base exposure: f/16, 1/4s, ISO 100
  2. Add ND1000 filter (10 stops)
  3. Result: f/16, 4 minutes, ISO 100
  4. Start timer
  5. Open shutter on camera
  6. Lock your phone (timer continues)
  7. When notification sounds, close shutter

Film Photography

  1. Select film stock (e.g., Kodak Portra 400)
  2. Set base exposure: f/5.6, 30s, ISO 400
  3. GeoLog applies reciprocity correction: 38s
  4. Start timer with corrected value
  5. Shoot with camera at corrected time

Astrophotography

  1. Calculate exposure: f/2.8, 20s, ISO 3200
  2. Start timer
  3. Timer countdown in silent mode (no light pollution from screen)
  4. Haptic pulse at completion
  5. Close shutter

Tips

Before Exposure:

  • Calculate exposure before arriving at location
  • Account for changing light (add/subtract stops)
  • Start timer before opening shutter (gives you prep time)

During Exposure:

  • Lock your phone to save battery
  • Timer runs in background
  • Check Dynamic Island for time remaining
  • Don’t worry about accidentally closing app

For Very Long Exposures:

  • Enable Low Power Mode to conserve battery
  • Live Activity still works in Low Power Mode
  • Consider external battery pack for >30 minute exposures

Timer Notifications:

  • Set GeoLog notifications to “Time Sensitive” for critical alerts
  • Notifications work even when phone is on silent

Settings

Stop Increments

Choose calculation precision:

  • Full stops (1, 2, 4, 8…)
  • Half stops (1, 1.4, 2, 2.8…)
  • Third stops (1, 1.3, 1.6, 2…)

Timer Preferences

  • Default sound/silent mode
  • Notification preferences
  • Auto-start timer after calculation

Troubleshooting

Timer doesn’t appear in Dynamic Island:

  • Requires iPhone 14 Pro or later
  • Check that Live Activities are enabled (iOS Settings → GeoLog)
  • Restart app if needed

No notifications:

  • Enable notifications for GeoLog (iOS Settings)
  • Set to “Time Sensitive”
  • Check Do Not Disturb settings

Timer stops when phone locks:

  • This shouldn’t happen—timer runs in background
  • Check that Background App Refresh is enabled
  • Update to latest iOS version

Related Features

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