rehess Loc: South Bend, Indiana, USA

Your use of language is unclear here. The precise wording is “That would make a person or object 1/2 the linear dimension, or 1/4 the area, on a negative or sensor, whenever the distance is doubled”. That is because inverse square law, or any square law, refers to areas increasing by square of linear dimension.

Charles 46277 Loc: Fulton County, KY

If you focus on a wall at any distance, and draw a rectangle on the wall that defines the edges of the image on the sensor, then back up to double the distance--you can then draw a new rectangle on the wall--4 times larger. This jibes with your formula of doubling the sides. Doubling the sides of a square gives you a square 4 times larger. It is when you look at objects in the picture, such as a person, that it looks complicated--because the background expands or contracts, including more or including less background, and the object or person gets larger or smaller in the picture. I think if a person is 1 inch tall on the sensor, and you cut the distance in half, the person will be 4 inches tall on the sensor--yes? (Pretend it is film large enough for this.)

Apaflo Loc: Anchorage, Alaska

You correctly described it, but then ignored what you said and state that at half the distance the vertical dimension is not 2x higher. It is 2x, and the area is what changes 4x.

Go to

http://www.tawbaware.com/maxlyons/calc.htm

Scroll down to the "Dimensional Field of View Calculator" to verify that the vertical dimension at half the distance is changed by 2x.

Charles 46277 Loc: Fulton County, KY

OK--I see. I stand corrected.