flektogon

The wide-angle Flektogon OF JENATHE HISTORY AND THE DIFFERENT VERSIONS OF THE GLORIOUS wide-angle CARL ZEISS JENA 2nd PART

THE HISTORY AND THE DIFFERENT VERSIONS OF THE GLORIOUS wide-angle CARL ZEISS JENA 1st PART second part

THE BIRTH OF OBJECTIVES CARL ZEISS JENAin the postwar period is constructed from 25mm wide-angle Topogon. All these objectives are characterized by an optical scheme with the center very backward and lens rear where so close to the focal plane to prevent their use on digital SLR. The only wide angle lens made by Carl Zeiss Jena in the postwar period for the reflex is a Tessar lens with a focal length of 40mm and f/4.5 maximum brightness. Apart from this goal dim and poor performance Carl Zeiss Jena is not able to offer in the early fifties no real wide angle lens for 35mm SLR. This is a common problem at the time to all optical industry, but that is brilliantly solved by the manufacturer optical Frenchman Pierre Angenieux presenting in 1950 the retro focus lens 35mm f/2.5. in the postwar period is constructed from 25mm wide-angle Topogon. All these objectives are characterized by an optical scheme with the center very backward and lens rear where so close to the focal plane to prevent their use on digital SLR. The only wide angle lens made by Carl Zeiss Jena in the postwar period for the reflex is a Tessar lens with a focal length of 40mm and f/4.5 maximum brightness.Apart from this goal dim and poor performance Carl Zeiss Jena is not able to offer in the early fifties no real wide angle lens for 35mm SLR. This is a common problem at the time to all optical industry, but that is brilliantly solved by the manufacturer optical Frenchman Pierre Angenieux presenting in 1950 the retro focus lens 35mm f/2.5.

http://www.nadir.it/ob-fot/zeiss_flektogon/flektogon2.htm

The diagram retrofocus lens is similar to that of a telephoto lens reversed, with the optical center of the lens and Tergal sufficiently far from the focal plane to allow the housing of the moving mirror. The Flektogon

The Carl Zeiss Jena is quick to assimilate the lesson Angenieux and realized in 1954 its first retro focus lens with pattern, baptizing in the name Flektogon, a new name that has never been recorded by Carl Zeiss before the war and which serves to identify all production of wide-angle lenses manufactured in Jena . Among the early fifties to the early nineties the wide-angle Carl Zeiss Jena builds signed with the name in the focal Flektogon 35mm, 25mm and 20mm for 35mm and 65mm focal lengths and 50mm SLR 6x6cm.

Flektogon 35mm

The first objective is a Flektogon 35mm f/2.8 to six lenses, is characterized by a shooting angle of 62 degrees on the diagonal and is constructed in the versions with bayonet fitting for Exakta, bayonet for Praktina and with screw plug. In the first version the Flektogon 35mm f/2.8 mounted the front ring of prediaframma BV and is finished in natural aluminum color. After the mid-fifties the Flektogon 35mm f/2.8 is built with Exakta bayonet mount version with semi automatic spring diaphragm SB and a lever for manual re-opening of the diaphragm.

Flektogon Flektogon Flektogon

35mm 35mm 35mm

f/2.8 - f/16 f/2.8 - f/16 f/2.8 - f/16

6 lenses 6 lenses 6 lenses

Angle 62 ° Angle 62 ° Angle 62 °

Focus 36cm - infinity Focus 36cm - infinity Focus 36cm - infinity

Filters 49mm Filters 49mm Filters 49mm

Weight 200 grams Weight 200 grams Weight 200 grams

Prediaframma BV Prediaframma BV Semi-automatic spring-SB

Screw coupling M 42x1 Exakta bayonet mount Exakta bayonet mount

Natural aluminum finish Natural aluminum finish Natural aluminum finish

At the end of the fifties is put into production the new version of Flektogon 35mm f/2.8 auto iris

spring ASB or ADB, with black finish and with the aperture ring clear. The minimum aperture is taken at f/22. In the automatic version, Flektogon 35mm f/2.8 is built with screw plug with a minimum focusing reduced to only 18cm, with Exakta bayonet mount with external button for closing the aperture and bayonet Praktina connected to the control mechanism the closure of the diaphragm of the model Praktina IIa.


35mm 35mm 35mm

f/2.8 - f/22 f/2.8 - 22 f/2.8 - 22






Prediaframma ADB Prediaframma ASB Prediaframma ASB

Screw coupling M 42x1 Exakta bayonet mount Bayonet mount Praktina (IIa)

Black finish with white rings Black finish with white rings Black finish with white rings

In the early sixties is put into production the third version of the Flektogon 35mm f/2.8. The finish is black with rings of apertures and focusing zebra. The new 35mm f/2.8 Flektogon retains the features of the previous version, including the diameter of 49mm filters. The minimum distance of focusing is reduced to only 18cm and for this reason, the objective is sometimes identified as Makro Flektogon. In this version the Flektogon 35mm f/2.8 is built only with universal adapter screw 42x1 and Exakta bayonet, after leaving the production of cameras Praktina. With bayonet Exakta the objective Flektogon 35mm f/2.8 is also built with black finish, typical of the production of the last seventies.


35mm 35mm 35mm

f/2.8 - f/22 f/2.8 - 22 f/2.8 - 22






Prediaframma ADB Prediaframma ASB Prediaframma ASB

Screw coupling M 42x1 Exakta bayonet mount Exakta bayonet mount

Black finish with zebra rings Black finish with zebra rings Black finish

In the eighties the Flektogon 35mm is changed, the maximum brightness of f/2.4 remaining becomes the formula of six lenses, and is built in black rings with blacks and with a minimum focusing to 20cm. Like other Carl Zeiss Jena last generation, the Flektogon 35mm f/2.4 is built in the version with the electrical contacts for connection to the diaphragm simulator of the Praktica LLC and the version with bayonet mount for Praktica B with aus Jena 35mm f/2.4 Prakticar name.

Flektogon Flektogon ELECTRIC PRAKTICAR - Flektogon

35mm 35mm 35mm

f/2.4 - 22 f/2.4 - 22 f/2.4 - 22






Prediaframma ADB Prediaframma ADB Prediaframma ASB

Screw coupling M 42x1 Screw plug M 42x1 electrical contacts Praktica B bayonet mount

Black finish Black finish Black finish

(End of the first part, the second part is here ) Danilo Cecchi © 03/2003

Flektogon 25mm

At the end of the fifties, Carl Zeiss Jena, working independently diagram retrofocus, manufactures a wide angle lens even more stringent than 35mm and can cover an angle of 82 degrees on the diagonal. The new lens is baptized still Flektogon, has the focal length of 25mm, the maximum aperture of f / 4 and consists of seven lenses, of which the front one particularly large, such as to require the use of filters to 77mm in diameter made of a special way not to cause vignettamento of the sides. The Flektogon 25mm f / 4 version is built with an automatic iris ASB is in the frame with bayonet mount for Exakta that in the frame with Bayonet Praktina, and finally in the frame with universal adapter screw. The Flektogon 25mm f / 4 focus from only 20cm from the focal plane and ended up at f/22 with a depth of field from 60cm to infinity.

Flektogon

Flektogon

Flektogon

25mm

25mm

25mm

f / 4 to 22

f / 4 to 22

f / 4 to 22

7 lenses

7 lenses

7 lenses

Angle 82 °

Angle 82 °


Angle 82 °

Focus 20cm - infinity



Filters 77mm (M 77W)



Weight 300 grams

Weight 300 grams

Weight 300 grams

Prediaframma ADB

Prediaframma ASB

Prediaframma ASB

Screw coupling M 42x1

Exakta bayonet coupling

Bayonet coupling Praktina (IIa)

Black finish with white rings



The Flektogon wide angle 25mm f / 4 is constructed in a version with black trim ring and zebra exclusively with bayonet mount for Exakta and the screw plug.

Flektogon

Flektogon

25mm

25mm

f / 4 to 22

f / 4 to 22

7 lenses

7 lenses

Angle 82 °

Angle 82 °





Weight 300 grams

Weight 300 grams

Prediaframma ADB

Prediaframma ASB



Black finish with zebra rings


Flektogon 20mm

In the mid-sixties the Flektogon 25mm f / 4 is joined and then replaced by a new wide-angle lens even more stringent, the Flektogon 20mm f / 4 to ten lenses, which covers an angle of 93 degrees on the diagonal: an angle greater than the 90 degree angle covered by the same Biogon 21mm f/4.5 made for the Contax rangefinder from Carl Zeiss in Oberkochen, and surpassed only by the Distagon 18mm f / 4 for Contarex created in 1967 by the same Carl Zeiss Oberkochen to cover an angle one hundred degrees. Flektogon The 20mm f / 4 focuses from 16cm from the focal plane, closes until f/22 with a depth of field that arrives from less than a foot to infinity. As in Flektogon 25mm f / 4, also in Flektogon 20mm f / 4 the front lens is large, and the diameter of the filters is of 77mm. The Flektogon 20mm f / 4 version is built with an automatic iris ASB in black finish with zebra rings, in the version with bayonet mount Exakta and one with universal adapter screw.

Flektogon

Flektogon

20mm

20mm

f / 4 to 22

f / 4 to 22

10 lenses

10 lenses

Angle 93 °

Angle 93 °





Weight 360 grams

Weight 300 grams

Prediaframma ADB

Prediaframma ASB





In the eighties the Flektogon 20mm is recalculated with only nine lenses, is brought to light with f/2.8 maximum gain of a diaphragm and is built with universal adapter screw version with black trim rings and blacks. The diameter of the front lens is reduced thanks to new optical formula, the diameter of the filters is increased to 67mm but the diaphragm continues to close until f/22 and the focusing distance is increased to 19cm from the focal plane. Like other objectives Carl Zeiss Jena of the last generation also Flektogon 20mm f/2.8 is constructed in the version with the electrical contacts for coupling to the diaphragm simulator of Praktica LLC and in the version with bayonet mount for Praktica B with the name Prakticar aus Jena 20mm f/2.8.

Flektogon

Flektogon ELECTRIC

PRAKTICAR - Flektogon

20mm

20mm

20mm

f/2.8 - 22

f/2.8 - 22

f/2.8 - 22

9 lenses

9 lenses

9 lenses

Angle 93 °

Angle 93 °

Angle 93 °




Filters 67mm

Filters 67mm

Filters 67mm

Weight 350 grams

Weight 350 grams

Weight 310 grams

Prediaframma ADB

Prediaframma ADB

Prediaframma ASB



Praktica B bayonet coupling

Black finish

Black finish

Black finish

Together with the objectives "Prakticar aus Jena" 20mm f/2.8 and 35mm f/2.4 is a lens in the catalogs "Prakticar aus Jena" 28mm focal length, consisting of eight lenses with f/2.4 maximum brightness which has no counterpart in production with screw plug. Given the promiscuity of the production signed "Prakticar Pentacon" and "Prakticar aus Jena" the origin of this wide-angle lens remains doubtful.

FOR Flektogon Pentacon Six

For medium format cameras Praktisix and then for the Pentacon Six Carl Zeiss Jena has built two magnificent family Flektogon wide angle lenses with auto iris type spring ASB. The first is a Flektogon 65mm f/2.8 to six lens that covers an angle of 64 degrees, closes up to f/22 and focuses from 75cm. The Flektogon 65mm is built up from 1956 aluminum and black finish and then with black trim rings and zebra. Rather large and heavy when compared with the Flektogon for 35mm, the 65mm Flektogon weighs almost a pound and fits 86mm diameter filters.

Flektogon

Flektogon

65mm

65mm

f/2.8 - 22

f/2.8 - 22

6 lenses

6 lenses

Angle 64 °

Angle 64 °



Filters 86mm

Filters 86mm

Weight 460 grams

Weight 460 grams

Prediaframma ASB

Prediaframma ASB

Bayonet mount Pentacon Six

Bayonet mount Pentacon Six

Aluminum finish and black

Black finish and zebra rings

The Flektogon 65mm is joined and then replaced by a Flektogon 50mm f / 4 to seven lenses covering an angle of 78 degrees, focuses from 50cm wide and become the ultimate system Pentacon Six. The Flektogon 50mm f / 4 is built from the early sixties to the late eighties, first with aluminum finish and black, then black with zebra rings, and finally the version with all-black finish and anti-glare coated version of MC. Compared to the Flektogon 65mm Flektogon 50mm protrudes more from the camera and weighs more, but is equipped with the same filters to 86mm in diameter.

Flektogon

Flektogon

Flektogon

50mm

50mm

50mm

f / 4 to 22

f / 4 to 22

f / 4 to 22

7 lenses

7 lenses

7 lenses

Angle 78 °

Angle 78 °

Angle 78 °




Filters 86mm

Filters 86mm

Filters 86mm

Weight 630 grams

Weight 630 grams

Weight 630 grams

Prediaframma ASB

Prediaframma ASB

Prediaframma ASB

Bayonet mount: Pentacon Six



Aluminum finish and black

Black finish and zebra

Black finish MC

Like the other mount lenses Pentacon Six, also the wide-angle Flektogon by 65mm by 50mm can be mounted on 35mm SLR with screw plug through the connecting ring, but this type of combination, in contrast to that with the standard lenses and Biotar Biometar with telephoto lenses and Sonnar, is impractical if not completely useless.

SUMMARY

Flektogon

35mm

f/2.8 - 16

0.36 - inf

Prediaframma BV

aluminum

49mm

VE

Flektogon

35mm

f/2.8 - 16

0.36 - inf

Semi-SB

aluminum

49mm

It

Flektogon

35mm

f/2.8 - 22

0.18 - inf

Automatic ASB

Black aluminum

49mm

VE PK

Flektogon

35mm

f/2.8 - 22

0.18 - inf

Automatic ASB

Black and zebra

49mm

VE

Flektogon

35mm

f/2.4 - 22

0.20 - inf

Automatic AM

Black MC

49mm

V VE B

Flektogon

25mm

f / 4 to 22

0.20 - inf

Automatic ASB

Black aluminum

77mm

VE PK

Flektogon

25mm

f / 4 to 22

0.20 - inf

Automatic ASB

Black and zebra

77mm

VE

Flektogon

20mm

f / 4 to 22

0.16 - inf

Automatic ASB

Black aluminum

77mm

VE

Flektogon

20mm

f / 4 to 22

0.16 - inf

Automatic ASB

Black and zebra

77mm

VE

Flektogon

20mm

f/2.8 - 22

0.19 - inf

Automatic AM

Black MC

67mm

V VE B

Flektogon

65mm

f/2.8 - 22

0.75 - inf

Automatic ASB

Black aluminum

86mm

PX

Flektogon

65mm

f/2.8 - 22

0.75 - inf

Automatic ASB

Black and zebra

86mm

PX

Flektogon

50mm

f / 4 to 22

0.50 - inf

Automatic ASB

Black aluminum

86mm

PX

Flektogon

50mm

f / 4 to 22

0.50 - inf

Automatic ASB

Black and zebra

86mm

PX

Flektogon

50mm

f / 4 to 22

0.50 - inf

Automatic ASB

Black MC

86mm

PX

Screw 42x1 V = E = Exakta PK = Praktina VE = Electric Screw Praktica B = B = PX Pentacon Six (Back to the first part) Danilo Cecchi © 06/2003 Article has also collaborated Norberto tubes.



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