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JFK Assassination System

Identification Form

Agency Information

Date:

9/21/201

AGENCY :

RECORD NUMBER:

RECORD SERIES:

HSCA

180-10127-10001

NUMBERED FILES

AGENCY FILE NUMBER :

008217

Document Information

ORIGINATOR :

DOI

FROM:

MULLEN, ROY R.

TO:

GOLDSMITH, MICHAEL

TITLE :

DATE: 05/10/1978

PAGES:

SUBJECTS :

PHOTOGRAPHS AND FILMS, BACKYARD, PHOTOGRAPHS

OSWALD, LEE, PERSONAL PROPERTY

DOCUMENT TYPE: REPORT

CLASSIFICATION: Unclassified

RESTRICTIONS : Consulted

CURRENT STATUS : Withhold

DATE OF LAST REVIEW: 06/08/1993

OPENING CRITERIA :

COMMENTS:

Report of Calibration of 620 Imperial Reflex Camera and a cover letter to HSCA. Box #:149.

v9.1

HH 48108

DocId: 32270041

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JFK

Routing Slip

008217

NO.

DATE MAY 1 0 1978

Document I.D. Incoming repor

Robert Blake

Gary Cornwel

Leogical Survey Kenneth Kietn

Calibration o

Charlie Mathews

Jim Wolf

of Camera sace ness

Hutton

Imperial tell Essenton

Team #1C

Team #3

ream f

Special Instructions:

Team#5

Howarth cover tatter

74 48108

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00821>

March 3, 1849

United States Department of the Interior

GEOLOGICAL SURVEY

RESTON, VIRGINIA 22092

526 National Center

May

3, 1978

Mr. Michael Goldsmith

Select Committee on Assassinations

U.S. House of Representatives

3331 House Office Building, Annex 2

Washington, D.C. 20515

Dear Mr. Goldsmith:

Enclosed is U.S. Geological Survey Report of Calibration No. 419 covering

measurements made on a 620 Imperial Reflex Camera, Commission Exhibit No.

Contained en yost letter of March 2, 1978.

These measurements have been made in accordance with instructions

The fee for this work is $320.

You will be billed for this amount

at a later date by our Finance Office.

Sincerely yours,

for Ray f, Bullen

Chief, Branch of Research

Technical Standards

Enclosure

48108

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USGS Report No. RT-R/419

United States Department of the Interior

GEOLOGICAL SURVEY

RESTON, VIRGINIA 22092

Camera type

Lens type

Nominal focal length

REPORT OF CALIBRATION

May 5, 1978

of 2 1/4 X 2 1/4 Camera

620 Imperial Reflex

77 mm

Commission

Identification

Exhibit No. 750

Maximum aperture

£/4.5.

Test aperture

£/4.5

Submitted by

Select Committee on Assassinations

U.S. House of Representatives

Reference: Letter dated March 2, 1978 from Mr. Michael Goldsmith

These measurements were made on Kodak Verichrome Pan film type 620

developed in D-19 at 68° I for 3 minutes with continuous agitation.

This film

was exposed on a multicollimator camera calibrator using a white light source

rated

at approximately 3500K.

I. Equivalent Focal Length: 77.55 mm

This measurement is considered accurate within 0.02 mm

II. Radial Distortion:

Field

angle

(degrees)

Do for azimuth angle

90

180

270

7.5

15

22.5

0

388

1706

61

611

-25

331

-_-

-44

260

1646

7

350

1767

The radial distortion is measured for each of 4 radii of the focal plane

separated by 90° in azimuth.

Dc is the average distortion for a given field angle.

Values of distortion De are based on the equivalent focal length referred to the

field angle co-tangent for 7.5

• The radial distortion is given in micrometres

and indicates the radial displacement of the image from its distortion free

position. A positive value indicates a displacement away from the center of the

field. These measurements are considered accurate within

10 um. It is clear

from these variations in the values reported among the four radii from the average

that a substantial amount of asymmetric distortion is present in this lens.

HH 48108

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USGS Report No. RI-R/419

III.

Resolving power in cycles/mm

Field angle:

0°

Radial lines

Tangential lines

14

20

7.5°

16

20

15°

20

10

22.5

--

the resolving power is obtained by photographing a series of test bars and

examining the resulting image with appropriate magnification to find the spatial

frequency the finest a teren he the bas eque enter it teasonable

cycles/mm in a geometric series having a ratio of the 4th root of 2. Radial

Lines are parallel to a radius from the center of the field, and tangential line.

are perpendicular to a radius.

IV. Indicated Principal Point

0

A

90

270

B

D|

180

Positions of all points are referenced

to the indicated principal point as

origin. The diagram indicates the

orientation of the referenced points

when the camera is viewed from the

back.

The direction of film travel is

to the top.

Indicated Principal Point

to Midsides of focal frame

B

C

D

Unable to Measure

28.79 mm

27.96 mm

29.34 mm

These measurements were made from a shadow image formed in the focal plane.

The method of measuring these distances is considered accurate within 0.01 mm.

The camera was aligned for calibration by autocollimating on the mounting

surface where the front of the test camera-lens was placed for the film

exposures. It is evident however that this is an indirect procedure, but the

only method possible for a camera of this type.

This alignment process made

the front of the lens ring normal to the axis of the collimator bean emergent

from the 0° collimator.

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USGS Report No. RI-R/419

V. Camera Negative

D

'The diagram indicates thé› .:

orientation, with emulsion

up of a negative submitted

for

focal frame measurements:

A

Distances between midsides

A-B

C-D

57.10 mm

57.14 mm

The method of measuring these distances is considered accurate within 0.01 mm.

William Pete

mwan

William P. Tayman

Branch of Research and Design

Topographic Division

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