4
4.
Depth of field
The area in acceptable sharpness in front of, and behind, the subjest in focus is called tole
Depth of Field. The aperture selected and e distance of the subject, as well as, the focal
length of a lens determines such depth of field.
Because of the longer focal length of your Reflex lens the depth of field is acutely narrow, for
example, with a 500mm f8.0 lens, at a distance of 6 feet, the depth of field is only 1/2 inch
wide. Therefore, it is recommended to first practice focusing with your lens before taking
any serious pictures, especially in close-up photography. lt is suggested that a focus
magnifier be used to help determine the depth of field sharpness under such extreme con-
ditions.
5.
Cleaning and maintenance tips
The lens should always be capped when not in use. Like other precision optics, it should never
be simply wiped with tissue since this may abrade the surface with any dust clinging to it or on
the lens.
Any accumulated dust should occasionally be blown off with a syringe or available blower
brush designed for this purpose. To remove fingerprints or smears, shred the edge of a lens
tissue and roll it to make a swab: dampen it with a lens cleaner specially. made for
photographic optics and gently wipe the surface without exercising any pressure. Repeat the
procedure if necessary using a new swab. To clean, start at the center of the lens, using a
circular motion and working to the edge of the lens for best results.
When the lens is not in use, it should be stared in a cool dry place, however, if this is not
possible, a leather case with a silica gel packet will afford the same protection as an aluminum
case with poly foam liner.
6.
Technical data
Lens speed
F5.6
Lens group/Lenses
1/2
Image angle
3,8°
Closest focusing distance
10m
Filter diameter
ca. 30,5mm
Front diameter
ca. 67mm
Overall length
ca. 298mm
Weight
ca. 505g
Shipment
1 x lens
1 x lens cap
1 x lens bag
