The LEE Filters Stopper app is designed to help you get the most from your Big, Little and Super Stopper filters by accurately calculating the exposure you require and offering a flexible timer for very long shutter speeds.

Tap the menu at the top to select your Stopper:
6 Stops = Little Stopper
10 Stops = Big Stopper
15 Stops = Super Stopper

Turn the left hand wheel to dial in your metered shutter speed (before you insert any filters) and read the adjusted exposure on the right hand wheel. (The app converts a full range of shutter speeds in 1/3 stop increments.)

You can use the built-in countdown timer for any exposure over 5 seconds to see in a glance how long you have left. For very long exposures you’ll also get a reminder notification plus all countdowns finish with an alarm.

You can download this app from the app store and play store.