Sociedad Ibero-Americana de la Historia de la Fotografia Museo Fotográfico y Archivo Historico "Adolfo Alexander"
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The PAL lens 

Author:

Fejér Zoltán

Translation and technical expanations:

Luiz Paracampo 

 

In October of 1998 Mr Greguss Pálnak engaged in the BME program said: - Acording to NASA papers several Hungarian technical developments were used in the Mars Space Program and this includes the various uses of the PAL Panoramic Annular Lens. This lens was invented and developed by  Majoros Sándor (1906-1970) one of the greatest optical researchers in Hungary. His name today, is almost unknown but he positively contributed to mankind in the reaching the stars.

In the year of 1940 Majoros Sándor worked at Gamma Optikai Múvék  with Barabás Jánossal (1900-1973) and together they planned three or four camera  objectives. From these, one went to be the first Duflex 1:3,5 normal objective , which was first named Artar , and after named Gammar. Majoros Sándor by that time had several tasks. He made also a greater aperture version, the f/2 -50mm that also Duflex used in an another version. In 1950 he too designed the Gamma greater focal length lenses (50, 75 and 105 mm), named Mayar , Magnetite  objectives. Although he had made great works, none of these were publicly reported.

When he worked at the Optikai Kutató Laboratórium (Optical Experimental Laboratory) in 1951-52, he developed various optical schemes for the military, one of them, a revolutionary tank periscope which could see everything in all directions at a time. The 360º sight periscope turned out to be used in all Hungarian Army tanks, and by extension, in every other Eastern European Country. The large scope allowed one to see at a single glance, enemies in the field. (Helicopters, etc.) From this date, and while Majoros Sándor was working at the “OKL” whole “security” scheme was mounted over him with guardsman all day long, by this reason,  Majoros Sándor  decided to give up his works and retire himself up to the end of his life.

Seventeen  innovations came out from the invention. The first one was to simplify the " Original Cyclorama”,  creating the new “Cyclorama tax mirror objective " now, with one single projector instead of the three originally used; not telling about simplification in regulations needed when using three projectors.  Another was told by Majoros Sándor  himself in 1961, who wrote  his biography during 1954 and 1960;  - " Just sheer for fun ".  Three of such instruments were also made for cavities studies making possible photographic examinations. Majoros Sándor recognized that the equipment must be employed with care - not swinging, rotating or so, in order to have  good visible images free of distortions and masking results. A former military artificer suggested a shorter focal distance of the lens easing passage through small curves. The equipment immediately found appliances in cannon and machine gun tubes for studying wear and small defects on producing and using such devices.

In the explanation leaflet of the PAL lens we see: " panoramic endoscopic view filmed around ” .  There was also made a Panoramic projector viewer where the perspective distortion  is completely corrected.

 

Explanation:

The panoramic annular lens (PAL) consists of a single piece of glass, with spherical surfaces, that produces a flat annular image of the entire 360º surround of the optical axis of the lens. This paper describes the attributes of the PAL and shows that the lens maps elements from object to image space via a constant aspect ratio polar mapping. A panoramic video system (PVS) is described to illustrate how the characterization can be applied in experimental mechanics for cavity inspection and measurement.

 

PICTURE 1

Left : (projector)

In the upper diagram we see the schematics of ray tracing in the PAL lens.

A’ B’ = viewing field (or projecting screen)   similarly D’ C’  (Images)

A’ A” A = A ray path   similarly D’ D” D

B’ B” B = A ray path   similarly C’ C” C

H = circle of view

PO = PAL lens (Virtual Imager)

HL = achromatic close-up lens (used in projection)

1, 2 = the two elements of the achromatic lens

VO = projector (or camera) lens

L’ = focusing point  = image plane

ABCD = circular image positioned points

K = Condensor

L = projection lamp

 

Right figure: (camera)

1 = peripheral reflecting surface

2 = central reflecting surface

3 = image entrance area

4 = internal reflected rays

5 = viewing area of the lens

6 = the PAL lens unit

7 = relay lens or camera lens

8 = camera

9 = image on film

10= image general appearance

a = vertical viewing angle

 

That way the two way optic can see the total of a cavity though an hyperbolic image. " Majoros Sándor  greater application are in examination of diseases, the tool not should rotate , or greatly swing, There are also light illuminated devides  with diameters not larger than 1,5 mm, Presently Japanese produce a complete set with a tolat of  0,6 mm in diameter. ( the domestic industry [Hungarian] goes down to only 2,5 mm). 

Everywhere are produced such devices, they do not mention the Majoros Sándor  152163- patent of a " panoramic view / projector ", nor the Greguss Pálnak 152163- patent by his schematics drawings  of the block scope map viewer.

Majoros Sándor  gave unconditionally in his testament the 152163- the patent profits to his elder sons. After his death there were suggestions to put his name on Budapest street near the  Petzval Joseph street.

PICTURE 2

PAL optical array diagram

 

PICTURE 3

Image obtained with  PAL lens

 

In 1960 Zeiss Winkel made some experiences with the idea but WILD Oberköchen  in 1965 made two commercial units for every one use. One for Contarex cameras and another for Minox. They were stravagantly priced (more than 5000 dollars)and enjoyed no success.

In the same decade the Americans made a toy-kind camera the Cyclorama camera and viewer. This viewer was very interesting because he had an in built gyroscope. One sees only part of the picture but when revolves his head, go seeing the whole surrounding scene. This kit at 169 dollars also enjoyed no success.