It often takes a lot of fiddling to get a perfectly exposed photograph. Whether you’re switching your camera’s settings back and forth or whipping out your light meter—just one more device to carry—it can be a tedious process. But thanks to Luxi, an incident light meter adapter for iPhone 5/5s, that’s totally changed. Now all it takes to get a perfect light reading, and in turn, a perfectly exposed photo, is snapping a ping pong ball-sized accessory into your smartphone.

First off, Luxi’s design is pretty incredible. It’s really as unobtrusive as possible both off and on your phone, where it wraps nicely around an upper corner to fit over the front-facing camera. Once in place, it looks totally seamless. Plus, with the number of devices we carry around these days, it’s nice to not have to lug around another one!

Here’s how the incident light meter works: The actual device is a small diffusion dome that measures the exact amount of light that falls on your subject, then shows the appropriate camera setting via an app on your smartphone. This type of measurement—vs reflected light measurement—isn’t affected by the subject’s reflectance or by janky light situations like extreme backlighting (so from now on, we’re only posing in front of the sunset.) Listen to Luxi, and you should get a perfectly exposed photo every time—simple as that.

Luxi is said to perform just as well as a number of expensive light meters, and at the insanely low price of $30, even the most snobby of camera snobs should want to give this photography gadget a try.

Would you use Luxi as your main light meter? Are there any other photography gadgets that we should know about? Tell us in the comments below!