NIKON COOLPIX 990 -
To reduce vignetting it is important to keep the eyepice as close as possible to the Nikon Coolpix 990 camera lens. The 20mm Sirius Plossel eyepiece is a perfect fit in the Universal Camera adapter in that it can be slid back against the 28mm to T-mount Adapter and the securing thumbscrew on the Universal Camera adapter still holds the eyepiece.
The longer 26mm Sirius Plossel requires a Edmund Industrial Optics short T-mount extension tube between the 28mm to T-mount Adapter and the Universal Camera adapter.
The shorter 10mm Sirius Plossel requires an Lumicon 1" thread-in extension tube (LAD110) mounted on the eyepice so that the securing thumbscrew on the Universal Camera adapter can hold the eyepiece.
© 1998-2003 David Haworth