Vivitar V-800MR Camera Lens User Manual


 
-6-
NOTE: In order to compensate focusing when normal positioning may be altered due to extreme
temperature change, the focusing ring has been designed to allow rotation beyond the xed
marks of the distance scale. To avoid mistakes, always focus while looking through the viewnder.
NOTE: No adjustments in focusing are necessary when taking infrared photography as required
with normal lenses.
4. Light and Contrast Control
Since the reex lens is not equipped with a diaphragm system, the use of lters plays an important factor in
the control of light and contrast.
5. Filters
Normal (IA Skylight): This lter should be used when no other lters are necessary.
ND 2X & ND 4X (Neutral Density): These lters control the passage of light since no diaphragm
is provided in the lens. Exposure factor is 4X with a ND4X, so that the light intake through the
lens is decreased as if a similar lens were stopped-down by 2 stops. Note that ND lters reduce
light passage only, while the depth of eld is not changed.