The Fisheye Converter FCON-T02 allows for circular fisheye shots without compromising the lens's brightness. Simply adjust the zoom position of the FCON-T02 to switch between circular fisheye and full-frame fisheye photography. It is designed to be waterproof, making it ideal for unique underwater shots. The interior of the lens is filled with nitrogen gas, preventing internal fogging due to temperature changes. With this unique accessory, you can achieve more dynamic images, and the wide-angle view fully captures the beauty of the underwater world.