When capturing a long exposure image with Spectre, the app takes advantage what's described as an intelligent computational shutter to take hundreds of photos over the course of a few seconds. Because it's taking hundreds of images instead of one continuous shot, you can hold your phone while you take long exposure images with Spectre.
Normally, these kind of long exposure shots require a tripod or another stable surface to come out well, but Spectre uses image stabilization and its computational shutter to simplify the process.
Spectre's software can also do some neat things with the long exposure images that you capture with the app. It can remove crowds if you take a medium or long exposure photo in a touristy area, and it can create those neat blurred effects you sometimes see from long exposure images when capturing flowing water.
At night, there's an AI mode designed to create light trails for creative nighttime shots and light painting purposes.
All photos captured by Spectre are saved as Live Photos, so you can see the end result as a still photo or see the exposure process from start to finish. Spectre supports 3 to 9 second exposures in the app, and while the long exposure features won't work for all types of images, you can still get a decent shot in most situations because it's simply stitching photos together.
Spectre can be downloaded from the App Store for $1.99. It works on the iPhone 6 and newer and requires iOS 11 and up. Scene Detection features require iOS 12, while AI-based stabilization requires an iPhone 8 or later.