- Black color headband binocular visor with three magnifying lens plates for hands-free viewing.
- Interchangeable lens plates provide 3X, 4X, and 5X magnification.
- Optical-grade acrylic prismatic lenses for improved focus and reduced eye strain.
- Visor tension-adjustment knobs allow visor to tilt out of way when not needed.
- Can be worn over prescription or safety eyeglasses.
The Donegan OSC Opti is a hands-free, headband binocular
magnifier that has an optical-grade, acrylic lens ground and
polished into a prismatic lens, and is available in multiple
dioptric strengths which provide a specific magnification power
(X) at a specified focal length, or distance from object. This
magnifier enhances the size and resolution of an object or image,
and is commonly used for a variety of applications, such as
jewelry-making, watch-making, needlework, artwork, electronic
inspection, book-reading, print inspection, and stamp-collecting.
The OSC Opti magnifier features replaceable binocular lenses
that have beveled edges, and are ed in an interchangeable
plastic frame. An adjustable headband with a padded leather
comfort band conforms to a variety of head sizes and provides
comfort for hours of continuous use. The magnifier can be worn
over prescription or safety eyeglasses. A durable, plastic visor
tips up above the forehead when not in use. Spring-loaded pivot
screws hold the visor in a raised or a forward-facing position.
The magnifier comes in assorted body colors such as black, and
blue. The magnifier weighs 0.58 lbs, and comes housed in a
protective shell and carrying case. It has a one-year limited
warranty.
Diopter (D) is a technical term for the measurement of the light
curvature and thickness of a lens. A dioptric number and a
magnification number are not the same thing. Diopter strength
represents a specific magnification power (X). For example, a
5-diopter provides 2.5X magnification (at a distance of 8”). The
higher the diopter, the more magnification a lens can provide. As
magnification increases, distance to the object (focal length),
and field of view (diameter, or narrowness of view) decrease.
Magnifiers and prescription eyeglasses have a diopter value, such
as 1.5 or 2. The dioptric strength of an accessory lens, such as
prescription eyeglasses or an eye loupe, must be added to the
dioptric strength of the magnifier to calculate total
magnification.
Magnifiers are devices used to the visual appearance of
an object or image. Magnifiers come in a variety of styles such
as hand-held, headband, standing, clip-on, eye loupe, and those
that hang in a necklace form, or fit in a trouser pocket.
Magnifiers are commonly made of plastic or glass. They can have
one or more lenses with varying magnification abilities, and can
have a binocular configuration with a single lens, or two
separate lenses. They are sometimes used with LED or fluorescent
light sources to help control viewing capabilities. Magnifier
ability is often expressed as magnification at a specific length.
For example, 1.75X at 14” means that when a magnifier is held at
14” from a viewer’s eyes, the object will be magnified 1.75 times
(X) its actual size. As magnification increases, viewing areas
and focal length decrease. Magnifiers sometimes have a diopter
number, expressed as + or - D, which is a measurement of strength
(or power) of the lens. Some magnifiers are marked with a
dioptric number on the lens. A high diopter number has a higher
magnification than a low diopter number. Aspheric magnifiers,
unlike spheric magnifiers,
Determining Magnification
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Diopter Magnification Focal length
(Distance from object) Sample view 20/20 vision 20" (50.8cm)
2-diopter lens 1.50X 20" (50.8cm) 3-diopter lens 1.75X 14"
(35.56cm) 4-diopter lens 2.00X 10" (25.4cm) 5-diopter lens 2.50X
8" (20.32cm) 7-diopter lens 2.75X 6" (15.24cm) 10-diopter lens
3.50X 4" (10.16cm) offers less distortion. Magnifiers are widely
used in jewelry inspection and fabrication, watch- making,
needlework, artwork, reading, print inspection, and
stamp-collecting.
Donegan Optical manufactures and distributes precision visual
devices for hobbyists and professionals in industry, home, office
and crafts applications. The company was founded in 1952 and is
headquartered in Lenexa, Kansas.
What’s in the Box?
* OSC Opti magnifier
* Fitted, plastic, carrying case
* Instruction manual