Specifications

On many lenses, your depth-of-field can be checked in the following way:
1. Focus the lens on the subject.
2. The main indicator line opposite the lens focusing scale will show the actual distance to the
subject.
3. A pair (or pairs) of lines alongside the main indicator will now show the range of subject
sharpness on either side of the subject that will also be in acceptable focus at one or more
aperture (F-number) settings.
For example, if you are using a 50 mm normal lens, set to f/16
and focused to 3.0 m (10 ft.), the two depth-of-field indicators
(for f/16) will show a range of sharp focus from about 1.8 m (6
ft.) to 7.6 m (25 ft.). Subjects within this range will be in good
focus. (Fig. 43)
14. INFRARED MARK
Always re-adjust your focus to the infrared focusing mark when
using infrared films and an R60 (or equivalent) filter. This is necessary because the image forming,
invisible IR rays have longer wave lengths than the visible light rays you see and focus with, and the
camera lens focuses them slightly further back inside the camera. Therefore, visual focusing can not be
accurate without some compensation.
1. Attach the R60 fiIter and visually focus on the subject. Read the indicated distance off the lens
barrel. (Fig. 44)
2. Shift that distance setting over to the red infrared index mark. (Fig. 45)
* Many lenses do not provide separate IR indicator, in which case some "Bracketing" of distance
settings may be necessary.
3. Set the exposure in accordance with operating instructions | for the film. I
* Always refer to film instructions for special precautions and procedures when any infrared film is
used.