When your iris changes in size from light why does does the area we can see not change?
In: Biology
I’ve been studying photography so I’m not an expert but I can share what I have found.
The iris affects two things, how much light is collected per unit time and how many angles of approach light has between the subject and the sensor (or film). When you open the iris wider you take in more light per second (or fraction of a second). You also allow more valid lines a ray of light has between what your camera is pointed at and the sensor. This is why the amount of distance which appears in focus shrinks, objects closer to or farther from the focal point have more lines they can take through that circle and still strike the sensor. A tight iris let’s in less light but only has a few lines it can take through the circle and strike the sensor, which increases the distance where things are in focus.
What affects how big the field of view is is something called the focal length. This answer is already pretty long so you can look into that if you like. HTH.
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