- Eyepiece (Ocular) Adjustments
- Before installing the scope, you should set
the focus of the eyepiece to fit your individual
vision requirement. The ocular focus is
pre-set
for normal 20/20 visual acuity. Re-focusing
the ocular distance will result in a sharper
reticle focus, an improved optical image
and avoid eye fatigue when using the scope
over prolonged periods of time.
- To focus the eyepiece, loosen the lock ring
and hold the scope about 3" to 4"
away from your eye (12" to 16"
for pistol scopes) and pointed at an unpatterned
area such as the sky or a solid painted wall.
If the reticle appears blurred when you first
glance at it, it is out of focus or not focused
for your eye. Turn the eyepiece counter clockwise
a couple turns and glance at the reticle.
It should be crisp and sharp to the quick
glance (continued study allows the eye to
adjust to an out of focus condition). Repeat
this adjustment until you see the reticle
crisply and clearly when you first look at
it. Once eyepiece focus is adjusted, tighten
the lock ring against the eyepiece to hold
it in place.
- On some model scopes the ocular lens adjusts
via a knurled ring at the end of the eyepiece.
Follow the same procedure as above except
there is no lock ring to tighten.
- Unless your eyes undergo a significant change
in acuity over the years, you will not
have
to make this adjustment again.
- Note:
- Occasionally, the lock ring can be difficult
to loosen. To loosen, simply hold the scope
tube firmly with one hand and turn the
eyepiece
with the other hand. This will loosen the
lock ring enough to be able to adjust.
- Parallax and Objective Focus
- Parallax occurs when the image rays from
the object being viewed do not fall precisely
on the reticle plane. Since a gap exists
between the two planes, moving your eye off
center to the edge of the exit pupil will
produce an apparent movement of the reticle
in relation to the target. If the eye is
not moved off center in the exit pupil, parallax
error cannot be discerned and there will
be no PI (point of impact) shift in firing.
When a scope is free from parallax, it is
also at its best focus.
Parallax is a negligible factor in scopes
of hunting power and, since neither the average
hunting rifle or factory ammunition is target
accuracy, the effect of parallax is not deemed
to be of significant importance to accuracy
in typical hunting situations.
However, parallax effect increases with an
increase of power and the scope's depth of
focus decreases. Therefore, in higher power
scopes such as target scopes and scopes used
for varminting, it is desirable to have some
means for adjusting parallax/focus at all
ranges as an integral part of the scope's
optical system.
- The most of high power (more than 12 power)
scopes have an adjustable parallax ring
typically
located on the objective bell. To set parallax
focus, turn the objective parallax ring
to
the mark which corresponds to the anticipated
or known shooting distance.
To set parallax focus on the locking parallax
adjustment scopes, loosen the parallax
lock
ring and turn the yardage indicator ring
to the desired range. Be sure to tighten the lock ring.
- Note:
- When a scope has been set free from parallax
error at a specific range, some error,
depending
on magnification and distance to the
target,
will still exist at all other ranges,
including
infinity.
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