Optics lessons.

Know that angled eyepieces offer more restful, long-term viewing than scopes featuring straight-through eyepiece alignment. FROM THE EXPERTS BIRDER AT LARGE BINOCULARS AND SPOTTING scopes are fundamental to birding. Smaller 32mm objective lenses provide more depth of field than 40-42mm objectives. Sleek roof prism designs are easier to hold steady than most wide-bodied porro prism designs by allowing users to reach the focus wheel easily and still keep their elbows close to the body, thus reducing hand shake and boosting image quality. [Extracted from the article]