Wista's compendium lens hood eliminates glare and restricts excessive lens coverage from entering the camera, and is truly an essential accessory for avoiding flare with long lenses. In particular, all lenses with focal lengths 300mm or longer as well as "fast" 210mm or 240mm f/5.6 lenses greatly benefit from such a hood.
The basic parts here are made of an aluminum alloy. It can be folded to save space, extended to 5.0" (127mm) in front of the lens shutter and screws neatly on to the rear of the Wista's front standard.
A hinge allows the hood to flip up and out of the way while you change lenses or adjust the shutter speed and aperture. When positioned for shooting, there's just enough space behind the lens hood to get the cable release to the shutter. Unlike some compendium hoods with filter slots, there will not be an open seam for light to hit the lens just in front of the filter with this one. The lens instead stays nice and shaded.
Since the hood rotates upon a circular axis centered upon the rear of the front standard, this hood may not be compatible with lenses having particularly long barrel lengths in front of their shutters(such as Nikkor's T-type telephotos). Additionally, the internal clear aperture of the mechanism is just 3.58" (91mm), so be sure that the maximum outer diameter of whatever is being used with the hood is not wider than 3.54" (90mm). It works best with traditional round threaded filters, but also is fine with the Cokin "A" filter holder system and the various smaller 3x3" gelatin filter holders from Canon, Hoya, Nikon & Pentax.