Sensor Size

The term "MegaPixel" when applied to a lens simply means that the diameter of the iris through the lens is large enough to work on a camera that has a total of 1 million (mega) or more pixels (whether that number is the "effective" or "total" pixels is up to the camera company's marketing team). Typically the higher the MP on a lens the larger the sensor you can use it on, but lens companies like to misuse the MP rating so take it with a grain of salt. What you really want to find out is the sensor size the lens is designed for. It will typically be in a fractional measurement, such as 1/2". For reference, the Hero 3 cameras from GoPro® have the following sized sensors: Black = 12MP 1/2.3", Silver = 11MP 1/2.7", White = 5MP 1/2.5" (more info here). Because the measurements are fractional, the larger the number on the bottom of the fraction the smaller the sensor, and vice versa. If you use a lens that was designed for a smaller sensor than your camera has, then you may get a ring of black cropping your captured image like this (which is a waste because then you have to crop your image down to the size of that lower resolution sensor). You're better off getting multiple cameras with less distorted lenses and stitching the footage together in post-processing. All of the lenses we sell do not crop the image, so even if it says it is designed for a smaller sensor it will still work perfectly. Remember, we professionally test all our lenses to make sure they will work as described on the camera model listed to support it.