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Dan FROMM



Dan Fromm est né en 1944
Il a suivi des études d'économie
a travaillé comme spécialiste
des modèles en économétrie,
comme prévisionniste
économique et comme statisticien
Mais il a toujours refusé de répondre
aux questions concernant
la valeur des actions
cotées en bourse

La photographie est une autre
de ses vocations
il a commencé la photo
dans le but d'enregistrer
les couleurs naturelles des poissons
tropicaux qu'il avait choisi
d'héberger et de nourrir chez lui
En plus des photos de ses poissons
il a préparé et présenté de nombreux
diaporamas et films de ses voyages
 dans les pays où il est allé
étudier les poissons

contact :
danielwfromm(at)hotmail.com

 

HTML-WEB formatting
by Emmanuel Bigler
 

Emmanuel Bigler is a professor in optics and microtechnology at ENSMM,
Besançon, France, an engineering college (École Nationale Supérieure
d'Ingénieurs) in mechanical engineering and microtechnology . He got
his Ph.D. degree from Institut d'Optique, Orsay (France). E. Bigler
uses an Arca-Swiss 6X9 FC view camera.

ENSMM, 26 chemin de l'Épitaphe 25030 Besançon cedex, France
Mail

See in pdf

L'article en français

 

 

 

 

Apo-Nikkor and Process-Nikkor large format lenses

by Daniel W. Fromm

1 Apo-Nikkors, according to Nikon

Nikon made two families of Apo-Nikkor lenses, both intended to be used for, e.g., photoengraving. These are, respectively, dialyte types (“Symmetrical Type Apo-Nikkor”)and Tessar types (“Asymmetrical Type Apo-Nikkor”). Nikon claims that all of them have low distortion (“almost zero” at 1:1) and are highly corrected for three colors, (“red, green, and blue”). “The highest sharpness will be attained when the aperture is stopped down by 2-3 stops from the maximum. When the aperture is reduced by 2 stops, a uniformly bright image area will be obtained without vignetting at the corners of the image field.” “Even when the aperture is stopped down, the image is maintained in the same position, so that focusing can be done at maximum brightness.”

 

I have an old Nikon catalog that says this about the two types:

1.1 Symmetrical Type Apo-Nikkor

Each Apo-Nikkor of symmetrical type, consisting of a symmetrically arranged optical system consisting of 4 groups and 4 elements of lenses, has the following features:

  1. The lenses will give a wide effective picture angle (about 46º) for their long focal length. Therefore, the image area being assumed the same, a camera of shorter length can be used.

  2. Since the lens system is symmetrical in respect to the iris diaphragm, the optical performance remains the same, regardless of the direction in which the lens is used. No need to reverse the lens for magnification. This greatly facilitates the use of the lenses mounted on a camera with automatic focusing device.

  3. The lenses are also suitable for work, where no distortion is permissible at a reproduction ratio close to full size. On the other hand, since the lenses give an excellent image, for a wide picture angle at infinite distance as well as in enlarging work, they can also be utilized for a large size camera or on an enlarger.


Figure 1: Symmetrical Apo Nikkor lenses, dialyte type, focal lengths 305 and 420 mm



Figure 2: Symmetrical Apo Nikkor lens, dialyte type, focal length 480 mm



Figure 3: Symmetrical Apo Nikkor lens, dialyte type, focal length 610 mm



Figure 4: Four Symmetrical Apo Nikkor lenses, dialyte type


1.2 Asymmetrical Type Apo-Nikkor

The asymmetrical type Apo-Nikkor lenses are intended primarily for reproduction of Japanese and Chinese characters. They have a rather narrow picture angle in order to attain highest resolving power. They can also be used as reproduction lenses in electrostatic photography and microphotography, as enlarging lenses for color and monochromatic photography, and in connection with general purpose cameras like view-cameras and studio-cameras.

2 Process-Nikkors, according to Nikon

Nikon made four Process-Nikkor lenses, all four elements in four groups double Gauss types with minimum aperture of f/32. Very similar –identical, but for the name – lenses were sold as Nikkor-Q before the name Process-Nikkor was used. Nikon does not claim that these lenses are apochromatic and does not recommend that they be used outside their usable range of magnifications.

I have a Nikon catalog that says this about them:

The wide picture angle design of Process-Nikkor lenses makes for larger subject area coverage than obtained with conventional lenses at the same working distance. In addition, this distance can be reduced for the same subject area, meaning the camera equipment can be compact.

Although the maximum aperture ratio is 1:10, these lenses have large diameters and minimal vignetting… 68° subject area coverage at full aperture or 74° coverage when stopped down to f/22.

Process-Nikkor lenses assure remarkable flatness of the image over the entire image area. They provide quick and low-cost photoengraving for monochromatic reproduction.

The lens construction is 4 elements in 4 groups, and their configurations are symmetrical so they can be used for either enlargement or reduction without reversing.


Figure 5: Process-Nikkor or Nikkor-Q lenses, double-Gauss type, were supplied in a nice wooden box



Figure 6: Nikkor-Q lens, double-Gauss type, focal length 260 mm; note the protruding rear lens element of this particular design.



f

max

   

mount

weight

(mm)

aperture

type

coverage

(mm)

(g)

150

f/9

tessar

45º

53x0.75

175

180

f/9

dialyte

46º

53x0.75

210

210

f/9

tessar

45º

53x0.75

185

240

f/9

dialyte

46º

53x0.75

220

300

f/9

tessar

41º

53x0.75

240

305

f/9

dialyte

46º

72x1

430

360

f/9

dialyte

46º

72x1

470

420

f/9

dialyte

46º

90x1

780

450

f/9

tessar

37º

72x1

550

455

f/9

dialyte

46º

90x1

810

480

f/9

dialyte

46º

90x1

860

600

f/9

tessar

37º

90x1

775

610

f/9

dialyte

46º

110x1

1450

750

f/9

tessar

37º

110x1

2015

760

f/11

dialyte

42º

110x1

1360

890

f/11

dialyte

42º

162x1.5

3600

900

f/9

tessar

37º

140x1.5

3570

1070

f/12.5

     

1600

1200

f/9

tessar

37º

213x1.5

8385

1210

f/12.5

dialyte

40º

162x1.5

3800

1780

f/14

dialyte

36º

213x1.5

6430

1800

f/14

tessar

35º 20’

213x1.5

8860

Table 1: Summary of Apo-Nikkors’ characteristics



           

Magnifi-

f

max

 

coverage

mount

weight

cation

(mm)

aperture

type

f/10, f/22

(mm)

(g)

(usable)

180

f/10

4/4 double Gauss

68º, 74º

62x1

350

1:4 - 4:1

210

f/10

4/4 double Gauss

68º, 74º

72x1

510

1:3 - 3:1

240

f/10

4/4 double Gauss

68º, 74º

82x1

730

1:2 - 2:1

(*) 267

f/10

4/4 double Gauss

68º, 74º

90x1

1070

1:2 - 2:1

(*) note: engraved 260 mm

Table 2: Summary of Process-Nikkors’ characteristics

3 Wide-angle Apo-Nikkors, according to Nikon

Steve Hamley very kindly shared a Nikon brochure on these lenses with me. The full text can be found at:http://www.largeformatphotography.info/forum/showthread.php?t=86484

Nikon made four Wide-angle Apo-Nikkors, all six elements in four groups plasmat types with minimum aperture of f/128. Nikon says explicitly that these lenses are apochromatic, "fully symmetrical," and that, although their published "usable magnification range" is 1:10 - 10:1, they "are equally suited for other precision optical tasks, such as: … use with view cameras or large format studio cameras."

f (mm)

max

type

coverage

mount

weight (g)

Magnification

 

aperture

         

150

f/8

6/4 plasmat

60º

53x0.75

240

1:10 - 10:1

210

f/9

6/4 plasmat

57º

72x1

455

1:10 - 10:1

300

f/9

6/4 plasmat

54º

90x1

840

1:10 - 10:1

360

f/9

6/4 plasmat

54º

90x1

970

1:10 - 10:1

Table 3: Summary of Wide-angle Apo-Nikkors’ characteristics

 

See in pdf

L'article en français

 

Dernière modification : 2012

 

 

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