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.