There are four objective lenses designed to give four unique perspectives.
There are four different versions with varying degrees of angle-of-view. You would choose one based on the look, subject or type of image you would like to produce. These, like the other two parts, can all be put together and disassembled underwater. You could keep all four objective lenses with you and swap out when needed. You can shoot these just like you would any other lens, but the real magic happens when you get up close to your subject.
The 160°, 130° and 100° objective lenses will focus as close as the front element and the 60° objective lens can focus as close as 15mm. You could fill up most of the frame with a nudibranch and still have room for a diver in the background! The EMWL is a great tool to boost your creativity.
100° Objective Lens 87222
This is an extremely versatile angle of view. It is the smallest and sleekest in physical size making it a good choice for timid subjects and tight spaces. It is designed with 9 elements in 6 groups. An angle of view of 100° is still a lot of background space for small macro subjects or to shoot wide angle with. A 16mm lens on FF is 107° for comparison.