Photron FASTCAM ultima APX-i2, Руководство по оборудованию

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FASTCAM-ultima APX-i2 Hardware Manual
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・ If the subject is stationary for long periods and you take image with the intensifier, this has a
tendency to burn the image into the intensifier. Do not shoot stationary scenes with the
intensifier over long periods of time (minutes) to avoid burning the intensifier screen.
・
Do your setup on the camera & intensifier at lower frame rates for focusing and Field-Of-View
adjustments. This will reduce the time that the intensifier is on at higher gain levels.
・
When the intensifier is not operating, shut the power off and place a cap on the lens.
⑪
Useful life of the intensifier
1. For a given period of operation time, the more input light exposed on the intensifier, the
shorter will be its useful life.
2. Allowing the intensifier to be exposed to high light intensities (high light input) over time will
deteriorate the intensifier gain.
3. For a given amount of input light, the higher gain setting that you use will produce a higher
light amplification with the intensifier but it will result in a shorter useful life.
4. The amount of input light and the accumulated length of time of exposure to input light
adversely affect the useful life of the intensifier.
⑫
Image quality
An image intensifier’s image quality is determined by many factors including the previous history of
use for the intensifier as well as the light amplification requirement, resolution of the intensifier,
wavelength of incoming light, coupling methods to an electronic sensor and other factors.
The image quality is affected the most by the intensifier’s previous use as well as the amount of
light amplification required to produce an image. Therefore, if more light can be used to illuminate
a scene, the better the image quality will be with the intensifier. The reason is due to the fact that
both noise and light are amplified with the intensifier. At higher gains, more noise is amplified as
well as the image signal, which heavily affects the useful life of the intensifier. It is a trade-off
between the useful life and image quality.
⑬ High-Speed Framing
An image intensifier has a finite life of use. The longevity of useful life is determined entirely by use
and environment. A high-speed camera takes images very fast. There is a direct relationship
between the number of exposures, the intensity of exposure and the frequency between
exposures that relates to the rate at which an intensifier is consumed. As the intensifier is
consumed, it will become less sensitive at a given gain (amplified) level. Therefore, more gain will
be required for the same application over time. In this case, time may mean months or it may
mean hours depending on how the intensifier is used and protected by the user.
For example, when the frame rate is doubled, the output of the intensifier must be doubled as well.
In this case, if the amount of input light is not increased, the intensifier gain will need to be
increased and the intensifier sensitivity deterioration is accelerated. Also, the same situation can
occur where excessive light is required in order to make image with low noise.
When the frame rate is set to higher than 2,000 fps (frame rate will be at a resolution smaller than
the full resolution), only a portion of the full frame can be displayed on the monitor. If there is a
strong light falling on a portion of the intensifier surface that is not displayed on the screen,
damage can occur without the user knowing the intensifier is being overexposed.
⑭
Use of electronic shutter of the imaging sensor
When the electronic shutter is used, the exposure time on the sensor is shortened. As a result, the
useful life of the intensifier is adversely affected because the intensifier has to operate at higher
gain levels since the imaging sensor needs more light output from the intensifier. As an example, if
the shutter speed of 1/1000 sec is used for 250 fps framing, the imaging sensor needs light input
amount equal to that needed for 1,000 fps. Therefore, whenever possible, set the shutter rate of
the camera at 1/frame rate.