Vivitar V-800MR instruction manual Light and Contrast Control, Filters

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.

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