Second Iris Diaphragm - P+S Technik pro35 Image Converter MKII User Manual

2.3.4 Second iris diaphragm "continuous ND-Filter":
In the practical handling with the PRO35 Image Converter, the aperture of the utilized lens is
mainly used for the defi nition of the desired depth of fi eld. The real exposure of the camera
results – like in classical fi lm productions – from light setup, from optical fi lters (in front of the
lens as well as internal ND-Filter) and / or from the utilization of the second iris diaphragm:
IMPORTANT: The visual depth of fi eld does NOT change by using the second iris dia-
phragm! Another aperture, which is located behind the second iris diaphragm, is only a kind
of light valve, because of the projection of the picture on the target. Consequently a precise
control of exposure is possible anytime. If the exposure trough an external servo-system is
desired, the aperture fl ange of the PRO35 is equipped with a geared ring.
Tip: Mask the working aperture during the fi rst days of production. Like this you get
used to the exposure correction with the second diaphragm.
Right in front of the camera there
is the second iris diaphragm.
It is engraved with ND (neutral
density) marks, in order to make
a correct exposure calculation
comparable to an ND fi lter.
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