Why doesn't the pictures of close-up scenes with my IS70 spotter look like what I see through the scope?
March 22, 2010
The IS70 has a camera and a spotting scope. However, they are two separate optical tubes separated center-to-center by almost 3 in. Because of this, the camera and the main scope actually have two slightly different lines of sight. This causes the image direction in the scope to differ from the image direction in the camera, a shift called the parallax or parallax angle of the optical system.
Parallax is usually not important because the scope is mostly used at distances of 50 ft or more where the angular shift is small. It is important at smaller distances when the camera is zoomed in, where the shift can amount to almost the entire field of view of the camera. (The IS70 main optics can focus as close as 8 ft.)
In this situation, what the main scope "sees" will not be the same as what the camera captures. Parallax will have shifted the scene out of view and off to the side.