Wirecutter recently posted a very comprehensive feature on on underwater photography, entitled "Beginner’s Guide to Underwater Photography". Several Nauticam housings are featured, including the NA-EM1, NA-7100, and the NA-RX100II. Here are some excerpts from the article.. the full article can be found here. The Wirecutter has teamed up with the ocean site The Scuttlefish, underwater photography experts at Wetpixel, and underwater photographer Sterling Zumbrunn to write this introduction to underwater photography techniques and gear. Have you ever wanted to take your camera snorkeling? Wanted to capture images when you’re scuba diving? Are you frustrated by the limitations of your waterproof point-and-shoot and left wondering how pros take those dramatic images in dive magazines? Underwater imaging is an exciting—though complex—pastime, yet it has never been more accessible than it is today thanks to digital cameras. This article seeks to demystify some of the most important concepts behind underwater photography and videography and provide our recommendations on the best cameras (and housings) available today for beginners looking to learn how to shoot underwater. 
During the past five years, one company has taken the underwater photography market by storm, making housing selection kind of a simple thing. Hong Kong’s Nauticam (distributed by Backscatter has consistently shown incredible craftsmanship in their housing development. Edward Lai, Nauticam’s owner, has decades of experience in manufacturing and is also an avid underwater photographer who started the business to solve some of his pet peeves with existing housings.
Nauticam makes housings crafted from aluminum for far more cameras than any other manufacturer, typically providing the best option for any given camera, with thoughtful ergonomics, innovative features, and good reliability. The net result is that they produce our pick of housing for the majority of cameras that we review in this article and the housings that are used by many people we know.
The article covers many aspects of underwater photography, and is worth reading in it's entirety. Grab a cup of tea or coffee, kick back and read it here