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E
FA
Q
6
When stopping down the aperture of the front lens at T4.0 or further, the struc-
tural pattern of the target becomes apparent. How can I avoid this pattern to
appear on my imagery?
In order to control exposure (i.e. when light is too intense like in bright daylight) without
affecting the depth of fi eld, we recommend to use the iris of the Image Converter.
If this ND function is insuffi cient and the image remains overexposed, closing the fi lm
lens iris may not offer the required limited depth of fi eld or may project too much grain on
the video image. Two possible remedies:
1) Use the ND fi lter of your video camera or
2) Use a ND fi lter in front of the fi lm/photo lens to decrease the light entering the system
We do not recommend to increase the shutter speed of the camera in order to control
exposure. In this case please consider, that the visibility of the target’s structural pattern
changes and might cause disturbance or interferences in your image. Although is possi-
ble to eliminate these interferences by adjusting the speed control of the target.
Is it possible to use the whole tolerance of the fi lm lens aperture together with
the PRO35?
We advise not to use the whole tolerance of the fi lm lens aperture together with the
PRO35. Stopping down the aperture of the front lens at T4.0 or further unveils the struc-
tural pattern of the target. In order to control exposure (i.e. when light is too intense like
in bright daylight) without affecting the depth of fi eld, we recommend to use the Image
Converter’s iris.
What is the highest aperture stop I can use without getting grain from the
target?
We recommend to avoid stopping down the front lens aperture further than T4.0.
I have got a colour gradient from top to bottom in my video image. What is it
and what shall I do?
This is so called “colour shading”, a gradual shift of the colour in upright direction due to
a mismatch of the lens system and the electronic system of the camera. To get further
information on this phenomenon and how to eliminate it, please refer to chapter 2.4.1.
The distances engraved on the fi lm lens’s focus ring do not match to the mea-
sured distances to focused objects. Is it due to a back focus displacement?
Yes. You have to adjust the back focus at the Image Converter.
How do I create a clean image?
For creation of a clean image please consider the following items:
* Back focus adjustment
* Colour Shading adjustment
* adjust the target’s oscillation speed
* control the camera’s shutter speed
* do not stop down the front lens further than T4.0
* Try setting the camera to manual mode and limit the gain to 0 db or even –3 db
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