I came across this review on the net...Is your lens notably different?
Zeiss 75mm f/4.5 Biogon Test Review
© 2005 KenRockwell.com back to 4x5 lens page
Developed in the 1950s and introduced in 1953 as an available-light ultrawide lens for shooting hand held wide open on press cameras, this lens is awful for use on a modern 4x5 because it has too little coverage (92 degrees or 153 mm image circle) to provide any movements. These lenses are only bought by rich impressionable amateurs who don't know how to use the movements on their 4 x 5" cameras. They also weigh a ton and are huge. You can buy these for about $600 without a shutter from a industrial surplus place in Pasadena, CA, ($1,200 with a shutter) or be an idiot and pay $2,500 for the same thing from a camera store. It is poor for real photography because it is huge and does not provide movements with its restricted 153 mm image circle. It's great for use on aerial cameras and working wide open, but that's not what you're doing on 4 x 5." A much better lens is the 75mm f/5.6 Schneider Super-Angulon or 72mm XL.
10 elements. The Hasselblad 38mm SWC lens is a simplified 8 element version of this.
92 degrees coverage, wide open or stopped down
153 mm image circle
Huge size and weight
Performance is spectacular wide open, which is great for aerial cameras and spy satellites, but meaningless for photography.
It has the usual cos^4 light falloff. What's unusual about this design is that it has no additional mechanical vignettting even wide open. it is designed to give full performance wide open.
Get one for your spy plane or hand-held press camera, but get a lens designed for a view camera for your view camera.[/COLOR]