Comments about Kenko Kenko 0.38x Semi-Fisheye Wide-Angle Conversion Lens for Digital Still Cameras with a 52mm Mounting Thread.:

The KNW-038 produces a circular image on my Nikon Coolpix 5400. The coverage is 150+ degrees. With the Panorama Tools plugin for Photoshop, the circular image can be converted to a rectilinear image covering over 100 degrees. The edges are soft, but acceptable for many purposes.

I tried the KNW-038 on several Nikon SLR lenses on a Nikon D-50. Every combination produced severe distortion and mushy resolution. It also puts too much front end weight on autofocus lenses. I recommend against this application.

The KNW-038 has a macro section that can be used separately as a high-powered front macro converter with pretty decent quality. I use it with my 55mm f/2.8 Micro Nikkor AIS and Nikon D50. The reproduction ratio is around 1:0.5, with a slightly curved field. I wouldn't buy the KNW-038 just for its macro function, but the macro function is a nice bonus.

This is a lens for photographers who know what they are doing. It won't work on every camera, and the increased coverage comes at the price of diminished image quality, especially at the edges.