# LuxCalc — Lighting Calculator

> Lighting calculator for exposure, photometry, and contrast ratios. (iPhone/iPad app by Boris Popovic.)

- Source: https://appshunter.io/ios/app/luxcalc/id1488382635 (this page in markdown: same URL + `.md`)
- Developer: [Boris Popovic](https://appshunter.io/developer/1488382634)
- Category: Productivity, Photo & Video
- Price: $2.99
- Age rating: 4+
- Requires: iOS 12.4 · 1 MB
- Languages: English
- Released: 2020-06-21
- Data updated: 2026-06-10
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/luxcalc/id1488382635/reviews.md

## What is LuxCalc?

Beautifully designed with a user-friendly interface, LuxCalc can calculate:

On the Exposure page, there are interrelations between luminance (in lux or foot candles), aperture opening, sensitivity, and exposure time. Aperture openings can be expressed as numeric (e.g., 6.3) or descriptive (e.g., 5.6+).

On the Photometry page: interrelations between luminance (in lux or foot candle), light intensity (in candela), and distance (in meters or feet).

On the Contrast page, the key-to-fill light ratio is calculated using the formula: (key + fill) / ill. Key light and fill light values can be expressed as luminance (lux or fc) or as f-stops.

In application settings, users can choose to express exposure time as a combination of frames per second and shutter opening (video style) or as fractions of the second (photo style). Exposure time, aperture opening, and sensitivity can be calculated to the precision of a full stop, a half stop, one third of a stop, or all three. Metric or imperial units, aperture notation (numeric or descriptive), and showing or hiding of calculated raw values for aperture, ISO, and exposure time can also be chosen in application settings.

In addition, the application presents a table of aperture openings between f1.0 and f22 in full, with one-third, half, and two-thirds stop increments, which is very helpful when interpreting digital light meter readings. Aperture openings can be shown as rounded or raw (calculated) values. Raw values are used in all calculations. A table of all ISO values between 6 and 25600, in full, one-third, half, and two-thirds stop increments, can also be presented.

A light-meter constant (C) is used in some of the calculations. Because it is a lesser-known property of light meters, here is a brief explanation from Wikipedia: The constant C should be chosen by statistical analysis of the results of a large number of tests conducted to determine the acceptability to a large number of observers of a large number of photographs for which the exposure was known, obtained under various conditions of subject manner and over a range of luminances. You should choose the value specified for your light meter or the generic (default) value of 280. Using this value, LuxCalc calculates 100 foot-candle luminance output for 24 FPS, 180-degree shutter opening, 2.8 aperture, and 100 ISO input (known as 100:100:2.8 Rule)

## Key features

- Exposure calculations (lux, foot candles, aperture, sensitivity, time)
- Photometry calculations (luminance, intensity, distance)
- Contrast ratio calculations (key-to-fill light)
- Customizable exposure time formats (video/photo)
- Precision settings for stops (full, half, third)
- Unit and notation customization (metric/imperial, numeric/descriptive)
- Aperture and ISO value tables

## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/luxcalc/id1488382635/reviews.md

### 5/5 — Love it

*2024-01-23*

Use this app all the time to compare lights and the fstop they would give me.

## Frequently asked questions about LuxCalc

### What lighting calculations can LuxCalc perform?

LuxCalc can calculate interrelations between luminance, aperture opening, sensitivity, and exposure time on its Exposure page. It also handles interrelations between luminance, light intensity, and distance on its Photometry page, and calculates key-to-fill light ratios on its Contrast page.

### Can I customize how LuxCalc displays exposure time?

Yes, LuxCalc allows you to choose how exposure time is expressed. You can select between a combination of frames per second and shutter opening for video style, or as fractions of a second for photo style.

### What precision options are available for exposure settings in LuxCalc?

LuxCalc offers precision settings for exposure time, aperture opening, and sensitivity to the nearest full stop, half stop, or one-third stop. You can also choose to display these values as rounded or raw calculated values.

### Does LuxCalc support different units of measurement?

Yes, LuxCalc allows users to select between metric and imperial units for their calculations. It also supports both numeric and descriptive aperture notation, as well as the option to show or hide calculated raw values.

### Is LuxCalc available on multiple devices?

LuxCalc is designed for Apple devices and is supported on iPhone, iPad, and iPod. It was released on June 21, 2020, and its latest version is 2.2, last updated on December 28, 2023.

### What is the price of LuxCalc?

LuxCalc is a paid application and is available for purchase at $2.99. There are no in-app purchases or subscriptions associated with this app.

### Does LuxCalc have ads?

No, LuxCalc does not contain advertisements. As a paid application, it provides an ad-free experience for its users.

### What is the age rating for LuxCalc?

LuxCalc has an age rating of 4+, making it suitable for a wide range of users. The app is categorized under Productivity and was developed by Boris Popovic.

## Version history (last 4 releases)

### 2.2 — 2023-12-28

The light meter constant (C) default value was changed from 330 to 280 to improve accuracy. If you feel that exposure calculations are not accurate enough, try experimenting with the C constant.

### 2.1 — 2022-07-23

Fixes the bug: the new version crashes if the previous version is still installed.

### 2.0 — 2022-07-12

Added lighting contrast calculation page
Improved navigation

### 1.0 — 2020-06-21

No release notes.

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## More apps by Boris Popovic

- [UDPtester](https://appshunter.io/ios/app/udptester/id1643157790)
- [Three Point Lighting Touch](https://appshunter.io/ios/app/three-point-lighting-touch/id6469644252)

All apps by Boris Popovic: https://appshunter.io/developer/1488382634

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*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 2026-06-10.*