How do you calculate the diameter of the aperture of a camera lens?
If I have a lens that is 50mm f/1.8, when the aperture is wide open, what is the diameter of the aperture opening? I think you determine it by dividing the focal length by the f stop, so 50 divided by 1.8 = 27.8mm. Is that correct?
What about a lens with a variable focal length… for a lens that is 70-300mm f/3.5-5.6 what is the diameter in mm of the aperture when the lens is at 300mm? Do you just do 300/5.6 = 53.6 still? That seems awfully big.
You are correct, and that is the correct answer.
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