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Anonymous
>>205251 Tell the medium and large format people to stick to the so called 35mm standard then. 80mm? Bullshit, it's a "40mm". As many film formats as there are sensor crops.
A focal length is a physical property.
>>205106 As for the OP, the aperture blades in a common lens nowadays will usually be found in the middle of the lens, often at the central intersection.
The f number designates the size of the light ray that is let into the camera through the lens. Lenses are spherical, allowing a beam of light of the f-number's diameter to enter at the lens' angle of view, forming an image of said f-number throughout the image.
If you were to put an aperture at the front, you'd be closing the field of view by a fuckton, and only the center would be useful. Your lens of said aperture is no longer giving you the field of view you were going for.
Additionally, about the f/0.012 thing, ignoring the fact that it's theoretically impossible, have you also realized how big a lens of any focal length would be? Here's something to think about: because of what I just said about the angle of the beam of light entering the front element, front elements generally have to be wider than their supposed focal length.
I could go on, but believe me, as I have learned myself, there is -way- more into optical design than one would think.
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