Abstract A conventional portable microfilming camera having a generally fixed exposure is improved for use with slower films which are required for x-ray duplication. The improvement consists of placing a neutral density filter over the exposure controlling photocell thereby reducing the amount of light reaching the photocell. This in turn results in a longer period of time being required for the pre-set amount of light to reach the photocell thereby causing a longer exposure time as required by the slower film. A light table is provided for back-lighting the x-rays and selectively sized masks are hingedly affixed to the light table for selective masking of the unused portion of the light table. A beam restrictor is used in conjunction with the neutral density filter to ensure that the photocell does not view the uncovered portion of the light table.
In combination with a camera designed for use with a standard film said camera being of the type having a lens and photocell which opens a shutter until a predetermined quanta of light from the subject area has entered said photocell, said predetermined quanta being nonadjustable; a photocell intake modifying device comprising: a neutral density filter having an operative position located in the optical path between the subject area and said photocell, said filter being of a density sufficient so that by the time said predetermined quanta of light has entered said photocell, said shutter has been open long enough so that a film slower than said standard film may be properly exposed; and a cylindrical tube hingedly attached to said camera adjacent said photocell and having an axis coincident with said optical path, said tube being of a length and diameter so that only light incident from the subject area to be photographed will enter said photocell.
Claim 2
Dependent Claim
158 words
In combination with a camera designed for use with a standard film said camera being of the type having a lens and photocell which opens a shutter until a predetermined quanta of light from the subject area has entered said photocell, said predetermined quanta being nonadjustable; a photocell intake modifying device comprising: a neutral density filter having an operative position located in the optical path between the subject area and said photocell, said filter being of a density sufficient so that by the time said predetermined quanta of light has entered said photocell, said shutter has been open long enough so that a film slower than said standard film may be properly exposed; and a cylindrical tube hingedly attached to said camera adjacent said photocell and having an axis coincident with said optical path, said tube being of a length and diameter so that only light incident from the subject area to be photographed will enter said photocell.
Claim 3
Dependent Claim
19 words
The combination of claim 1 wherein said filter is located at the end of said tube opposite said photocell.