Here are some facts... not speculaton :wink:
An ajustable objective lens allows you to focus at distances over 100 yards and adjust for a condition called Parallax. The scopes with adjustable objective lenses have markings that allow you to adjust the focus for specific ranges, which in turn allows you to find the range you are shooting at easily :idea: .
Parallax occurs when viewing distant targets, and the reticle appears to shift or move. This occurs when the image in the scope is in one focal plane, and the reticle is in another. Most scopes without adjustable objectives are factory set to compensate for parallax and focus at an optimum distance of 100 or 150 yards. Parallax is usually only an issue at magnification over 10 power. When looking at a scope that will be used for distant targets in higher power, an adjustable objective is a good choice. :!: