In the 70s, Leica made a special reflex camera for document copying. It uses bulk 35mm film up to 30 meter. It attaches to Reprovit.

It had multiple format

• 32x45
• 22.5x32
• 24x36
• 18x24
• 14x20

Lens : 70mm/f5.6

This camera is the first 35mm camera to use vacuum sucktion to maintain flat film plane.

-- martin tai (martin.tai@capcanada.com), January 22, 2001

Answers

How do you get 32 x 45 on a film with only 24mm available image width?

-- Bob Fleischman (RFXMAIL@prodigy.net), January 22, 2001.

It used unperforamted 35mm bulk

-- martin tai (martin.tai@capcanada.com), January 23, 2001.

Among the Leica Docuflex formats:

32x45
22.5x32 
24x36
18x24
14x20



   The following  three formats
32x45
22.5x32 
14x20
  have  aspect ratio  1:square root of 2, the so call perfect aspect
ratio.  Paper with such aspect ratio, when cut into two equal halves
the smaller oblong papers retain the same  1:1.4 aspect ratio



  Which is the basis for DIN A,B,C for document paper sizes.



  Camera with frame of 1:1.4  is perfect for copy documents



  Another famous camera with this perfect aspect ratio is Minox 8x11
  8x11  is DIN B14 standard size, coupled with Minox's close focus
capability and specially made Minox copy stand with click stop for
DIN A3,A4,A5,A6, makes Minox the ideal camera for espionage 
document copying. Minox camera can copy DIN size drawings, documents 
with perfect proportion and minimum loss of film area and document 
area.
   Among the Docuflex formats 24x36 is standard 35mm format, 18x24
is so call 'half frame"
    24x36 frame has an aspect ratio 1:1.5, its half 18x24 has an 
altered aspect ratio of 1.33

-- martin tai (martin.tai@capcanada.com), January 12, 2002.

Without calculation, one can at once recognize 32x45 as two familiar aperture stop numbers on large format camera, f32,f45,f64

Of course we all know two consecutive F numbers on lens has a ratio of 1: sqrt(2)

Similarly for Minox 8x11; apparently F8, F11 are two consecutive aperture stops, naturally has 1:sqrt(2) ratio.

1: Sqrt(2) ratio means doubling of area. In camera lens, the area of lens opening doubles from one aperture to next.

In DIN standard paper, the area of A3 is double of A4

-- martin tai (martin.tai@capcanada.com), January 12, 2002.

Two photographic papers have 1:sqrt(2) aspect ratio

• 3.5x5"
• 5x7"

3.5x5" is half of 5x7" requiring exactly half the amount of exposure during enlarging

The next larger size with this ideal aspect ratio is 7x10; unfortuntly there is no 7x10" paper.

-- martin tai (martin.tai@capcanada.com), January 12, 2002.

Minox 8x11,A Camera with Ideal Format

-- martin tai (martin.tai@capcanada.com), January 12, 2002.

Martin: Get a grip, man!

(But thanks for the Documentation on the Docuflex - we learn something new every day - or die.)

-- Andy Piper (apidens@denver.infi.net), January 12, 2002.

In a thread in photo.net about Aspect ratio, golden means... Roland touched upon the concept of ideal format with aspect ratio 1:sqrt(2). However he was incorrect about its absence in photography.

-- martin tai (martin.tai@capcanada.com), January 12, 2002.

In enlarging 35mm negatives, I notice that with the current available BW paper, it is difficult to enlarge without forced cropping.

There is no 4x6" or 8x12" BW paper on the market.

8x10" is not the same 24x36 proportion, nor its half 5x8",and half 4x5"

Minox enlarging is another story, there is no force cropping with 3.5x5" and 5x7" size papers.

In Europe, I think there is a 8.5" x12" paper with ideal 1:sqrt(2) ratio

-- martin tai (martin.tai@capcanada.com), January 12, 2002.

To understand the significance of Leitz Docuflex ideal formats 32x45, 22.5x32, 14x20; and Minox 8x11, see

DIN PAPER SIZES

I don't think the topic of no cropping enlargement and copying has being discussed here

-- martin tai (martin.tai@capcanada.com), January 12, 2002.

24x36 the famous Oskra Barnack format, as aspect ratio of 1:1.5.

It came from doubling of 18x24 movie frame, which has aspect ratio of 3:4 ? What is the significance of 3:4 and 1:1.5 ?

At the beginning, there was no compelling reason tha Barnack must double up 18x24 into 24x36... He could have chosen 24x34, which will make Leitz an ideal format.

Walter Zapp is ingenius camera designer, he thinks much deeper than Oskra Barnack

-- martin tai (martin.tai@capcanada.com), January 12, 2002.

Martin: Barnack's format is PERFECT. It's the paper manufacturers who got the format(s) wrong. 8^)

The Greeks' "golden mean" ideal format was 1 : 1.6(something or other), as reflected in the proportions of the height to width of the Parthenon. 35mm's 1:1.5 ratio is the closest format currently available to the "golden mean".

-- Andy Piper (apidens@denver.infi.net), January 12, 2002.