The latest 360-degree cameras are vying for differentiation with tweaks and nifty features at every price point. Most have two lenses and sensors plus software to stitch their output into a spherical image. Some offer weather-sealing and shock absorption, and many take memory cards. A few features once reserved for ultra-high-end cameras, such as stereoscopic 3-D, have made their way into consumer models; 4K video is becoming standard. Here are a few of the newest.