stan (03/29/83)
Complex lenses do not absorb a lot of light because they have "a lot of glass". They pass less light because of reflections from the many glass/air and glass/glass surfaces. This scattered light also causes flare, which reduces contrast. The "cure" for this problem is multi-coated optics. A zoom lens with ~15 elements ought to have a transmission of >90% if it's multi-coated. If not, then who knows, the transmission might be closer to 50%. For detailed discussion of this problem and T-stops in general, I refer you to a yearly manual of the American Society of Cinemaphotographers (ASC). As always, if anyone out there knows where I can get a copy of this, please let me know (by mail). Stan King phone: 201-386-7433 Bell Labs, Whippany, NJ Cornet: 8+232-7433 room 2A-111 uucp: floyd!stan
jeff (04/01/83)
The Bell & Howell Foton 35mm RF camera (late 40`s) had Taylor Hobson Cooke (British) lenses calibrated in T-stops. If anybody has a Foton and would like to sell it I`d be interested. Try 607-256-4075. Jeff Frey