Section V Model 196A
Paragraphs 5-8 to 5-12
camera off (figure 5-3, insert A) will look like insert on the film will be in focus) depends to a great extent
C with the camera in place, and will produce a picture on the aperturesetting of the camera. In cases where 1
on the film as in insert B. Parallax problems can be it is important that both the graticule and the trace be
minimized by positioning the cathode ray tube against in perfect focus, depth of field must be considered.
the oscilloscope bezel.
5-10. APERTURE EFFECTS. Aperture, the actual
diameter of the lens opening, is described in terms
of f/number which is the relationship between the focal
length and the apparent diameter of the lens (f/number
RT PHOSPHOR = f/d, when f = focal length of the lens and d = the ap-
parent diameter of the lens). Figure 5-3 shows a
typical oscilloscope bezel and demonstrates the effect
I of aperture size on depth of focus and depth of field, It
GRATICULE LINES should be fairly apparent from examination of figure
5-3 that because of the cathode ray tube phosphor and
graticule separation, the aperture must be closed
somewhat in order for both thegraticule and the trace
to be in focus at the same time. In the 196A, the aper-
ture must be set to about f/5.6 or smaller (f/number
5.6 or higher) for both the graticule and trace to be in
PERTURE FILM'
LO-l-1.l focus .
GRATICULE GLASS
5-11. FILM PROCESSING.
5-12. After the film has been exposed, the operator
pulls the negative tab on the right side of the camera.
I
Rollers (figure 5- 1) force the negative and the positive
Figure 5-3. Aperture Effects on Depth of Field sheet together, breaking pods of developer (one for
each exposure) and spreading this reagent between the
negative and the positive sheet. After the developing
5-8. DEPTH OF FIELD. period, the back access door is opened and the positive
print is removed. The film meanwhile, has been auto- 1
5-9. GENERAL. Depth of field (the range of object matically advanced one frame, and is ready for the
distances within which the image formed by the lens next exposure. A
3
5-2 01038- 1 |
ACEC
