Linhof Viewfinder d-dx 8 R WR Aspherical is

8 R WR Aspherical is a compact wide-angle lens for the Fuji X mount

It provides a 1

this Canon Powershot A550 might do the trick

Covers Micro Four Thirds towards the telephoto end- and it's real close to filling the frame in square format

6GII ED AF-S Nikkor lens for Nikon DX-format digital SLR cameras

Linhof Viewfinder d-dx 8 R WR Aspherical isThis Linhof viewfinder is suitable for 4x5 and 5x7 cameras, with variable fields of view from 90mm (or 120mm, for 5x7) to 360mm (or 500mm). It's adjustable for portrait or landscape shooting, too, which is handy. These viewfinders are mostly useful as a framing aid: you can use them mounted to the camera, or as a handheld "director's viewfinder. The view through the optics is satisfactory, though you'll need to refocus your eye to see the framelines