Why Is The Image Easier To See When Enlarged?; Image Quality And Resolving Power - Canon 10 x 30 IS Manual

How clearly the binoculars let you
distinguish details is called their
resolving power. Because the unit area
of conic vision cells in the retina of a
human eye is low, no physical training
will be able to increase, up to a point,
the resolving power. The only way to
increase it is to look through a good
pair of binoculars. If you use 10x
magnification binoculars, you will have
10x more resolving power than normal.
With the naked eye, you will not be able to read text past a certain
distance, but with the binoculars, because the resolving power is
increased, you will be able to read it.

Image quality and resolving power

Not all binoculars will provide the magnification ratio and
resolving power indicated on the instrument. When there
is too much aberration, there is not enough resolving
power. No matter how superior the binoculars may be,
the resolving power will decrease because of image shake.
The larger the magnification ratio, the more the hands will
shake that image. In general, binoculars with magnification
of over 10x are not recommended for hand-held use.
To eliminate this problem, Canon has adopted its superior
optical technologies gained in developing camera lenses. In
addition to using the doublet field-flattener, UD lens and
aspherical lenses to achieve ideal resolving power, Canon has
used its own original image-stabilization technology (in the IS
series), which greatly controls hand shake. It is because of these
technologies that with Canon' s binoculars, each feather on a
bird' s wing comes in crisp and clear.
A sharper image–right down to
the bird' s wings.
Magnification / Resolving Power
Because of lens aberration, the
entire image appears blurry.