Enter Spotliter Video, a free app that provides a choice of distinctive filters for video recording. It is, quite simply, like Instagram for video, though without the integrated sharing options.
It works like this: fire up the app, then tap to choose an effect from the scrolling selector along the bottom. Spotliter offers a dozen of them, but not just the usual assortment of sepia, black-and-white, and so on.
Rather, you get effects like B&W2COLOR, which blends the image from black and white on one end to color on the other. But if you tap or drag on the image preview, you'll see the effect move to match where your finger lands. The same is true of Floodlight, which darkens all but a finger-specific area. If you're using your iPhone to shoot, say, a fun little home horror movie, you could do some really cool stuff with this effect.
Many of Spotliter's other filters offer similar real-time tweaking. Nightclub, for example, is a trippy posterization-style filter that detects motion, but you can also tap anywhere to highlight that portion of the image or swipe to "flash" across it. (This is better seen than described.)
Then there's Magnify, which zooms a size-adjustable circular area while leaving the rest of the shot at 1x. You pinch to increase or decrease the size of that circle, or tap if you want it elsewhere than the center of the preview. I found myself wishing for the option to blur the edge of the circle, which appears in sharp contrast to the unzoomed area, but that's a small nit.
What's especially nice about shooting with Spotliter is that you can pause and then resume recording. That's great if you want to make minor adjustments to an effect or even switch to a different one within the same clip.
When you're done, the app saves your recording to its own folder within your library. It lacks any kind of editing or sharing options, but obviously you can accomplish those kinds of things with other tools.
For the amateur videographer, Spotliter offers some slick effects you won't find elsewhere for a price you can't beat. It's definitely worth a look.