Trouble Shooting
Common Image Problems
Vignetting occurs when the image does not fill the complete field of view, resulting in black corners.
Many digiscopers use software to crop away dark corners.
Adjusting the distance between the eyepiece and camera lens can reduce
the amount of vignetting by more closely matching the exit pupil of the
scope with the entry pupil of the camera. Jay Tuberville provides a
more complete explanation of vignetting and how to eliminate it.
The shadowing on top right is the result of light leaking between the camera lens and the eyepiece.
Experience in holding the camera next to the eyepiece of the scope, or in using an adapter, will help eliminate this problem.
Zooming
the camera lens results in a closer match between the image size of the
camera and the image size of the scope, resulting in less vignetting.
Greater magnification, however, can lead to a darker image and
increased sensitivity to vibration.
High quality spotting scopes use special coatings and lens materials to maintain image brightness and sharpness.
Blurring
can come from moving the camera as the shot is being taken or by
vibration from wind and other factors. The tripod page and tips page include information on reducing vibration.
