Browse Prior Art Database

Light Control for Electronic Flash Unit

IP.com Disclosure Number: IPCOM000095298D
Original Publication Date: 1965-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Stump, GP: AUTHOR

Abstract

In order to provide the proper amount of light from photographic flash unit 10, sleeve 11 carries a plurality of neutral density light filters. Each filter has a different filter density. Sleeve 11 is precalibrated. Thus, a filter density can be chosen which controls light output for making good exposures over a range of distances most often encountered. The known maximum distance at which flash unit 10 produces correct exposure is the object distance for the zero density or transparent filter. The distance scale is on the rim of sleeve 11 and is read from the rear of flash unit 10. When taking a picture, it is only necessary to dial the distance on the rim of sleeve 11 to select the filter to provide the correct exposure at the desired object distance.

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Light Control for Electronic Flash Unit

In order to provide the proper amount of light from photographic flash unit 10, sleeve 11 carries a plurality of neutral density light filters. Each filter has a different filter density. Sleeve 11 is precalibrated. Thus, a filter density can be chosen which controls light output for making good exposures over a range of distances most often encountered. The known maximum distance at which flash unit 10 produces correct exposure is the object distance for the zero density or transparent filter. The distance scale is on the rim of sleeve 11 and is read from the rear of flash unit 10. When taking a picture, it is only necessary to dial the distance on the rim of sleeve 11 to select the filter to provide the correct exposure at the desired object distance.

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