Perfectly Clear ($2.99 for iOS and $1.99 for Android)
What it is: an app with 12 automatic corrections to improve photos shot with a smartphone. The iOS version costs more because it includes noise removal and other features. When the Android version is updated with these tweaks, it will also cost $2.99.
How it works: The app applies scientific formulas to make photos resemble images the way we actually see them, because the camera filters light differently than the human eye does. The app automatically overcomes 12 ways in which the camera can distort an image, including color, depth and vibrancy. You can shoot photos within the app or correct photos that were previously shot.
Why it's great: Even when I think I've taken a fantastic shot, the app improves it by automatically brightening the image, improving exposure, etc. A three-bar menu button adjusts settings, such as Exposure and Sharpen, but I have discovered that the one-step Automatic Correction is the best fix. The app is a great tool to use before using another app to create a collage or special effects.
Why you might hesitate: It adds a square frame to rounded borders, but this quibble is irrelevant if I clean up an image in Perfectly Clear before using an app with borders such as Diptic.
Diptic (99 cents for iOS)
What it is: an app that allows you to create a collage with as many as nine images.
How it works: After launching Diptic, you choose from 160 layouts and then select photos for each frame in the collage. You can adjust the dimensions of each frame by moving the joints. A filter can be added and characteristics, including brightness and hue, can be adjusted. You even can alter the border width, color or round its edges. While the collage is being uploaded to Twitter, Facebook, email, etc., the app indicates it's working with messages, including "It's rock and roll time."
Why it's great: After photographing a meal with another travel writer, I walked away with app envy after I saw him create a collage of our appetizer, cocktails, entree and dessert with Diptic, while I had four stand-alone images. I downloaded the app that night and have been enjoying it nonstop, whether I want to memorialize a meal, zip lining or a day in the life of my cats.
Why you might hesitate: No reason to hesitate unless you hate collages.
ReelDirector ($1.99 for iOS)
What it is: an app that allows you to edit and create compilation videos shot with your iPhone and/or iPad.
How it works: You launch the app, create opening and closing credits, and then add videos and stills from your device's photo library or from your iCloud photo stream. You then choose among 28 available transitions between clips or scenes. Transitions include fade through black, fade through white, cross-dissolve, etc. Voice-overs and music can be added, including songs from iTunes.
Why it's great: It's easy to use and enables you to improve the pace or enhance your footage with stills and sound, especially because music can often make or break a movie. ReelDirector allows me to trim videos to the right length to work with other video apps such as Viddy, which produces only 15-second videos.
Why you might hesitate: No undo feature to go back a step. The app grabs a song only from the beginning, so you can't select a particular segment or refrain. You also can't preview the entire movie before you render it. But you can re-edit after rendering, so this isn't a deal breaker.