Olympus i-SPEED 2, Instructions Manual

Page: 93 / 116

Understanding ispeed
91
i
--SPEED LT,
i
--SPEED 2
An illustration is given from the experience of the
i
-- SPEED LT,
i
-- SPEED 2 development team. A car parts manufacturer wished to
view a rapid movement in the mechanism of a prototype seatbelt
reel. The scene was illuminated with several 1,000 watt garden
floodlights, but this was sufficient for only a few hundred frames per
second. The lighting was removed and replaced by a single
specialised 500 watt spotlight and this permitted operation at 1,000
fps. When faster operation was required, the spotlight was
augmented by an Olympus Industrial light source and liquid light
guide and this increased the operating speed to 4,000fps.
This example is included to show that the quantity of light is
significantly less important than the concentration of light. Olympus
representatives are able to supply specialised lighting which has
been selected to be suitable for most high speed video
applications.
`
View Finder
In contrast with some inferior products, the Olympus
i
-- SPEED LT,
i
-- SPEED 2 camera presents the live image on the CDU or monitor
screen at all possible times. Some menus do require the image to
be obscured and the splash screen logo is used for this purpose.
Also, the playback screen is used to display the contents of the
memory buffer, rather than a live image. During the live view and
the record process, however, the screen will display a live, colour,
real time image, updated at 60 frames per second.
`
Lenses
The choice of lens can make a dramatic difference to the video
images obtained.
Choosing the lens must begin with the focal length, which is
expressed in mm. A lens with a large focal length would normally
be chosen when a small area is to be viewed or the camera is to be
a long distance away from the scene, because a longer focal length
means a greater magnification. This type of lens has the
disadvantage of reducing the apparent distance between objects
which are arranged axially with the camera. This is called
foreshortening. Lenses with long focal lengths also tend to have a
smaller maximum iris setting (higher f number) and are therefore
dimmer than long focal length lenses.