On a frigid orbit beyond Neptune, some of the solar system’s smallest worlds project a strange silhouette. Two rounded lobes, pressed together with a narrow “neck,” like a snowman that never melted.

I’ve been testing two charming examples of this formula: the $99 Camp Snap Pro (aka CS-Pro), which is an upgrade to the original Camp Snap and looks like an all-plastic Fujifilm X100, and the ...