Lomography Diana + & F+ Lenses Field of View

In a previous post I calculated the f-stops of the Cloudy, Partly, and Sunny, settings for the various Lomography Diana + & F+ lenses. Now I will dig out a trig textbook and do the same for the field of view. It bears mentioning that when I type field of view I should be calling it the angle of view. Angle of view is the same thing in a sense but it’s represented by degrees while field of view is properly described as a specific distance. I should first note that this is based on the horizontal field of view and that I performed the calculation for both the 42x42mm mask and 52x52mm mask. After before I figured it out on paper I stuck three strips of tape over the mask, took the back of the camera and sat it on a tripod in my basement (creatively ’cause the tripod socket is on the camera back). That done I put a pair of lamps at the far end of the basement and moved them apart until each bulb just fit in the frame of the 42×42 mask. Then I measured the three sides of the triangle from the lens to each lamp together with the distance of each lamp from the other. Then some different trig calculations were made, those values are called “practical” in the table below. I was only able to do this for the three lenses I currently have. Here’s what I came up with:

20mm Fish-Eye lens

42×42 = 92.8°     52×52 = 105°

38mm Super-Wide lens

42×42 = 57.9°.    52×52 = 68.8°     practical = 53.8°

55mm Wide lens

42×42 = 41.8°     52×52 = 50.6°

75mm Normal lens

42×42 = 31.3°     52×52 = 38.2°     practical = 33.9°

110mm Soft-Telephoto lens

42×42 = 21.6°     52×52 = 26.6°     practical = 24.4°

What’s interesting is that Lomography doesn’t provide this information anywhere that I’ve found unless you count this where they describe the 38mm Super-Wide as “…yielding a 120° view angle.” Or this where the 20mm Fish-Eye is presented as having “[a] 180-degree image!” Which is interesting, as you can then immediately see that the sample images contradict the claim.

Translations from a Box of Soviet Medium Format film (120)

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Свема

Svema

ЦВЕТНАЯ

Color

ДС-4

DS-4

Негативная для дневнога

Negative for the day (daylight color correction)

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45 гост 18 DIN 50 ASA

45 gost 18 DIN 50 ASA

Врем проявл. [7] мин

Development Time [7] min.

Обработать до [09 85]

Process to [09 85] (Use by September 1985)

Партия No [3019]

Party no [3019]

8 кадров 6 x 9 cm

8 frames 6 x 9 cm

12 кадров 6 x 6 cm

12 frames 6 x 6 cm

16 кадров 6 x 4,5 cm

16 frames 6 x 4.5 cm

Цена 95 коп.

Price 95 cop. (copecks)

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СССР

The USSR (Union of the Soviet Socialist Republics)

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шосткинское проиэводствекное обединение „свема“

Shostkinsky (Shostka) production interconnection (association) “Svema”

ТУ 6-17-622-74

TU 6-17-622-74 (no clue)

вскрывать и обрабатывать в темноте

open and handle in the dark (panchromatic film)

Notes:

The translations above were typed into google translate with the help of this online Cyrillic keyboard. Text as printed on the box appears in bold above, and standard type below. Information that was imprinted on the box appears in brackets and translators notes added for clarity appear in parentheses. I don’t know the Russian language beyond a few bits here and there I picked up when I had a lot of enthusiasm for it after reading Gogol’s Dead Souls, great writer Gogol, you should read his work.

Lomography Diana + & F+ f-Stops

110mm Soft Telephoto Lens:

Sunny: f32

Partly: f22

Cloudy: f16

75mm Normal Lens:

Sunny: f22

Partly: f16

Cloudy: f11

55mm Wide Angle Lens:

Sunny: f16

Partly: f11

Cloudy: f8

38mm Super Wide Angle Lens:

Sunny: f11

Partly: f8

Cloudy: f5.6

20mm Fisheye Lens:

Sunny: f5.6

Partly: f4

Cloudy: f3

Source: Published values for the 75mm lens as they appear in Plastic Cameras Lo-fi Photography in the Digital Age by Chris Gatcum. Using those, the aperture diameters were computed as follows: Sunny 3.4mm, Partly 4.7mm, Cloudy 6.8mm. With that aperture f-stops were calculated with the formula: Lens Focal Length / Aperture Diameter = f-Stop