ZOOM 240 OPTICS FIELD OF FOCUS AND THEIR RELATIONSHIP TO THE 1540 LIGHT TABLE VIEWING SURFACE

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B05171A000400030029-9
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 2
• Document Creation Date: December 28, 2016
• Document Release Date: June 6, 2005
• Sequence Number: 29
• Publication Date: July 29, 1971
• Content Type: MF

Approved For Release 2005/06/23 CIA-RDP78BO5171A000400030029-9
IEG/OD/TPB-130/71
29 July 1971
1IM"_LO_R6.P R:_Chief_, Research and Engineering Division,... TSG.._._._.
Chief, Engineering Support Division, TSG
THROUGH Chief, Operations Division, IEG
SUBJECT Zoom 240 Optics Field of Focus and Their
Relationship to the 1540 Light Table
Viewing Surface
1. Request that RED and ESD look into a potential prob-
lem area that may exist with the Zoom 240 microstereoscope
and the 0 1540 Light Table. The field of focus for the
Zoom 240 using 2X stereo objective lens at 6OX magnification
is approximately .002 inches. The 1540 Light Table has a
specified viewing surface flatness tolerance of + .015 inches.
This large tolerance for the table tops may be causing focus
problems for the 240's in the stereo mode. The PIs have. been
complaining about the 0 240's, hoiwtever, our troubles may lie
with the 1540's.
2. IEG is also considering the development of 3X stereo
and mono objective lens and 15X wide field eye pieces. The
field of focus for the 3X objective lens will be less than
that for the 2X's. This increase in magnification will com-
pound the focus problem. With the increase in system magni-
fication, stability of the scope mount and bridge on the 1540
may also become a trouble area. -
3.- Request the above mentioned areas be looked into and
the following questions be answered.
a. Is there a focus problem using the 2X stereo
objective lens with a total system magnification
of 60X?
b. If there is a problem, what is required to solve
the problem?
c. Will the 3X lens considered for development
compound the problem?
Declass review by.
A'p$r8%e or Release 200 *j( I ?-tIA-RDP78B05171A000400030029-9
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IEG/OD/TPB-130/71
29 July 1971
SUBJECT: Zoom 240 Optics Field of Focus and Their Relationship
to the 1540 Light Table Viewing Surface
2 - NPIC/TSG/ESD
1 - NPIC/IEG
1 - NPIC/IEG/OD
2 - NPIC/IEG/OD/TPB
Approved For Release 200106/2'3 : CIA-RDP78BO5171A000400030029--9
"'4. Request this information be forwarded to IEG/OD/TPB,
d. Is the 1540 bridge and scope mount stable
enough for a total system magnification of 135X
in mono and stereo modes?
e. If the 1540 is not stable enough, what is the
max system magnification?
-Distribution:
by 16 August 1971.
Chief, Technical Planning Branch
Original $ 1 - NPIC/TSG/RED
25