LExp

Landscape Photography Planner and Exposure Toolkit for iPhone

Magic Hours showing sunrise, sunset, golden hour and blue hour times.

LExp for iPhone with tools for planning light and calculating exposure

SkyMeter Forecast showing the potential for colourful skies at sunrise and sunset

Sun Tracker map showing sunrise and sunset directions for a selected location

LExp long exposure calculator for working out shutter speeds with ND filters

LExp exposure tools for photographing the night sky

LExp overview of 20+ tools for photo planning, exposure and field reference

Plan the Light. Get the Exposure Right.

Choose a viewpoint for sunrise, see when blue hour begins and check whether the clouds might catch colour. When it's time to shoot, find the shutter speed for a long exposure on the coast or a night under the Milky Way. Built by a landscape photographer for use in the field.

SkyMeter Forecast

Check sunrise and sunset colour potential for the next 48 hours at your location. See the Sky Colour Index (SCI), cloud layers, fog and wind. The free preview shows local solar times. The live forecast requires LExp Premium.

Sun Tracker

See where the Sun will rise and set on a map for your chosen date and location. Check its direction and elevation to help choose a viewpoint.

Magic Hours

Check sunrise, sunset, golden hour, blue hour and civil, nautical and astronomical twilight at your current location. See the Moon phase and when the Moon will rise or set.

Exposure Calculators

Work out your shutter speed with ND filters, estimate exposures in low light or plan a sequence for star trails. Each calculator includes guidance for using it in the field.

FROM ND FILTERS TO THE NIGHT SKY

Use Recalculate Exposure to swap ISO, aperture and shutter speed while keeping the same exposure. Find starting settings for the northern or southern lights, or correct for reciprocity failure when shooting long exposures on Fujifilm Velvia 50.

Stacked & Graduated ND Filters

Calculate your shutter speed with up to two stacked ND filters of up to 20 stops each, with exposure compensation if needed. For a graduated ND filter, meter the sky and foreground to find the strength you need.

Moonlight & Nightscapes

Get a starting exposure for a moonlit landscape, even when the foreground looks too dark to judge by eye.

Milky Way & Still Stars

Estimate the longest shutter speed that keeps the stars looking sharp in a Milky Way or other night-sky photo.

Star Trails

Work out how many frames you need for a sequence you'll stack later. Preview the arc the stars will trace over your planned shooting time.

Moon Photography

Find a starting exposure for photographing the Moon itself, taking its phase, your focal length and shooting conditions into account.

Solar & Lunar Eclipses

Find suggested shutter speeds for each phase of a solar or lunar eclipse. Preview how large the Sun or Moon will appear in your frame at your chosen focal length.

LExp long exposure calculator for working out shutter speeds with ND filters. Calculate your shutter speed with up to two stacked ND filters of up to 20 stops each, with exposure compensation if needed. For a graduated ND filter, meter the sky and foreground to find the strength you need.

LExp exposure guidance for photographing moonlit landscapes and landscapes at night. Get a starting exposure for a moonlit landscape, even when the foreground looks too dark to judge by eye.

LExp exposure tools for photographing the Milky Way and stars. Estimate the longest shutter speed that keeps the stars looking sharp in a Milky Way or other night-sky photo.

LExp exposure tools for photographing star trails - work out how many frames you need for a sequence you'll stack later. Preview the arc the stars will trace over your planned shooting time.

LExp exposure guidance for photographing the Moon. Find a starting exposure for photographing the Moon itself, taking its phase, your focal length and shooting conditions into account.

LExp calculators with suggested shutter speeds for solar and lunar eclipses. Find suggested shutter speeds for each phase of a solar or lunar eclipse. Preview how large the Sun or Moon will appear in your frame at your chosen focal length.

IN THE FIELD

Built-in Exposure Timers

Start a countdown from your calculated shutter speed in supported calculators. The countdown keeps running in the background.

Countdown Alerts

Get alerts with 20, 10 and 5 seconds remaining and when the exposure time is up.

Favourite Screen

Set your most-used screen as a favourite so you can get straight back to it when you open LExp.

To download LExp app, visit the App Store

REFERENCE GUIDES

ND Filter Cheat Sheets

Look up how different ND filter strengths affect shutter speed. Zoom in on charts for filters up to 20 stops.

Flowing Water & Fireworks

Find shutter speed starting points for softening or freezing flowing water and for capturing the light trails of fireworks.

Photography Resources

Find the North and South Celestial Poles for star trails. Browse illustrated guides and links for landscape, low-light and night photography.

Whether you're waiting for sunrise, stacking ND filters beside a waterfall, photographing the Milky Way or preparing for an eclipse, LExp helps you spend less time calculating and more time making photographs.

LExp contains ND filter reference charts and cheat sheets, Flowing-water shutter-speed guide, Fireworks photography reference guide, Guide to locating the North and South Celestial Poles, and many additional photography notes, formulas and shooting advice throughout the app.

SCREENSHOTS

LExp exposure guidance for photographing the Moon and moonlit landscapes

LExp calculators with suggested shutter speeds for solar and lunar eclipses

LExp photography reference charts and shooting guides

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MEET THE DEVELOPER

ILYA GENKIN

Photographer / Developer

WHAT PHOTOGRAPHERS SAY

Great app

I recently invested considerable sum into the Lee filter system for my Nikon D800. This app is a perfect match, allowing me to quickly calculate proper exposure for various filter combinations. While I have yet to shoot in the field since getting all my filters, I've played with the app enough to know it will be quite handy. It also got a recent update, so its nice to know development is active.

Must have!

Not just a calculator. Excellent multitool with lots of professional tools for many photo/video needs. Important - each instrument has own very informative and helpful HELP menu, as well as a learning base. Beside that - quick, professional and friendly customer support. Highly recommended and huge respect to authors and developers!

Great application

I am professional nature and landscape photographer and this application is must have for me. I often use it for calculating exposure for star trails images and still stars too. I don't use ND filters but ND grad filters calculator is also very useful. Other strong side of the app - very good documentation and great library of useful links on photography resources.

Really useful

I use it as a pocket reference guide. It's really easy to use, especially when you are not an expert on doing the required calculations for neutral density filters.

Questions answered!

This app will not make you a photographer, but it will help you create photographs. Awesome help, thank you!

A very handy tool

This is a great tool to use for night photography and blurred or frozen motion. Goes into great detail to explain how to capture stars across several popular techniques. I love this app.

Very useful

If you are serious about long exposure photography - this app is definitely for you. Simply love it!

Perfect!

Takes the guess work out it, less trial and error. It allows you to be more efficient, accurate and productive. Easy to follow with the information you require at your finger tips.

This is the one!

Tried a few similar apps but this one is the best for me. Easy to use with many functions and clear explanations! Thanks.