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Steiner Comfort Harness

Steiner Comfort Harness

N$395.00 Ex Tax:N$395.00

One of the lightest binoculars in its class. Fully multilayer-coated lenses ensure image brightness and a crisp, clear visual experience. All lenses and prisms are made with Nikon’s Eco Glass, which is free of lead and arsenic. The fiberglass-reinforced polycarbonate design is highly durable, waterproof and fogproof. Rubber armouring enhances shock resistance and supports the firm, comfortable grip. Turn-and-slide rubber eyecups with multi-click adjustments facilitate positioning the binoculars to the correct eye point. The long eye relief makes it easy to enjoy a clear and full field of view, even for users who wear eyeglasses

Compact and lightweight 42mm-objective lens diameter model for superior portability (565g for 8x42, 575g for 10x42)

Wide apparent field of view (53.4° for 8x42, 62.9° for 10x42)

High-reflectivity silver-alloy mirror coating applied on the mirror surfaces of the prisms for a bright and clear view.

Multilayer-coated lenses for bright images

Long eye relief design ensures a clear field of view, even for eyeglass wearers

Lead- and arsenic-free glass is used for all lenses and prisms

Turn-and-slide rubber eyecups with multi-click facilitate easy positioning of eyes at the correct eyepoint

Waterproof (up to 1m/3.3 ft. for 10 minutes) and fog-free with O-ring seals and nitrogen gas

Rubber armouring for shock resistance and a firm, comfortable grip

Lightweight body uses fiberglass-reinforced polycarbonate resin

1 x Nikon Prostaff P3 10x42

1 x Nikon Bag

1 x Nikon Strap



What are binoculars?

Binoculars are a parallel combination of two telescopes for viewing an erect image with both eyes. Because they are designed so that an image of the same size can be viewed with both eyes, users can observe objects more comfortably than with a single eye. Also, the perspective and three-dimensional effect of binoculars make viewing more enjoyable.

Types of binoculars

Binoculars are classified as follows:

Differences between astronomical and terrestrial telescopes

An astronomical telescope (Keplerian telescope) uses convex lenses for both objective and eyepiece lenses, and the image is inverted. It is designed to give objective lens optical performance top priority and minimize light loss, so a prism to rectify the image is not incorporated.

A terrestrial telescope incorporates a prism between the objective and eyepiece lenses to rectify the image. It is convenient to observe erect images of landscapes and objects.

Galilean binoculars

Galilean binoculars are so called because they feature the same structure as that used in the instrument first used by the Italian astronomer Galileo Galilei for astronomical observation in 1609. These binoculars consist of convex lenses for objectives and concave lenses for eyepieces and form erect images.

Because no prism is employed, the binoculars can be made compact and lightweight. However, maximum magnification is up to about 4x. Generally, the field of view is not wide, and the peripheral areas of the field are likely to be out of focus. Opera glasses are usually of this type.

Prism binoculars

Convex lenses are used for both objectives and eyepieces. A wider field of view and high magnification can be attained than is the case with Galilean binoculars. An erecting prism system is incorporated in the optical path to rectify the image. Also, employing prisms has the effect of making the length of such binoculars shorter. There are two types of prism binoculars: Roof (Dach) prism type and Porro prism type.

Porro prism binoculars

Porro prism binoculars create an erect image with two prisms (four prisms total with both sides). This was invented by Ignazio Porro in Italy in the middle of the 19th century and has the longest history among prism binoculars.


Roof (Dach) prism binoculars

The roof prism system is used to rectify the image for this type of binoculars. "Dach" means roof in German, and this type of prism features a roof-shaped surface. The optical path at the objective side and eyepiece side is virtually straight, making it possible for the binoculars to be compact and lightweight. However, manufacturing and adjusting the prism require very high technology. Demand for this type of binoculars is expected to grow as more customers prefer its slim, stylish design.


Porro prism binocular
Roof (Dach) prism binocular

Magnification

This is the ratio of the apparent size of an object in comparison with what a viewer sees with the naked eye. For instance, an object 800m away viewed through 8x binoculars looks about equal in size to an object 100m away viewed with the naked eye. The higher the magnification, the more unstable the image will be due to hand movements. Higher magnification also results in a narrower field of view and lower brightness. Binoculars with magnifications up to 12x are recommended for general use. Also, using a tripod to prevent hand movements is highly recommended. Binoculars incorporating a VR (vibration reduction) function reduce image shake even at a high magnification.

Calculation of magnification:
  • Magnification= Effective objective diameter ÷ Exit pupil diameter
    = Focal length of objective lens ÷ Focal length of eyepiece lens

What is the relationship between the focal length of SLR cameras and the magnification of binoculars?

An interchangeable lens with 50mm focal length (in 35mm format) offers about 1x magnification. The effect of 8x binoculars is equivalent to that you can obtain by using a 400mm (50mm x 8 = 400mm) lens.

Effective diameter of the objective lens

The effective diameter is the inside diameter of the objective lens frame. With the binoculars designated with a numerical formula 8x42 7.0°, 42mm is the effective diameter of the objective lens.

Given the same magnification, the larger the objective diameter, the greater the light-collecting power. This results in higher resolution and a brighter image. However, large-diameter objective lenses make binoculars bigger and heavier.

Binoculars are classified according to the effective objective lens diameter as follows.

Effective diameter
  • Below 25mm:Compact-type binoculars
  • 30 - 49mm:Standard binoculars
  • Over 50mm:For astronomical observation and business use

Exit pupil

The exit pupil is the bright circle that can be seen in the center of each eyepiece when you hold the binoculars about 30cm away from your eyes with the objective lenses pointed toward a bright light. The larger the diameter is, the brighter the viewfield is, which is an important consideration when using binoculars in dark situations and for astronomical observation.

Exit pupil = The effective diameter of the objective lens ÷ Magnification

With 8x42 binoculars, the formula is 42 ÷ 8 = 5.3.
Therefore, the diameter of the exit pupil is 5.3mm.
This figure indicates the brightness of the image in view.

What is the relationship between bright/low-light conditions and the exit pupil of binoculars?

The pupil diameter of human eye changes depending on the ambient light conditions.

In low-light conditions (comparing 8x20 and 7x50 binoculars)

8x20 binoculars

  •  With 8x20 binoculars
    •  Pupil diameter of human eye: 7mm
    •  Exit pupil of binoculars: 20÷8=2.5mm
    •  Because the 2.5mm exit pupil of binoculars is smaller than the 7mm human pupil, you will perceive images as dark.

7x50 binoculars

  •  With 7x50 binoculars
    •  Pupil diameter of human eye: 7mm
    •  Exit pupil of binoculars: 50÷7=7.1mm
    •  Because the human pupil is about the same size as the binoculars' exit pupil, you will perceive images as bright as when seen with the naked eyes.

In bright conditions (comparing 8x20 and 7x50 binoculars)

  •  With 8x20 binoculars
    •  Pupil diameter of human eye: 2-3mm
    •  Exit pupil of binoculars: 20÷8=2.5mm
    •  Because the human pupil is about the same size as the binoculars' exit pupil, you will perceive images as bright as when seen with the naked eyes.
  •  With 7x50 binoculars
    •  Pupil diameter of human eye: 2-3mm
    •  Exit pupil of binoculars: 50÷7=7.1mm
    •  Because the binoculars' exit pupil is larger than the human pupil, you will perceive images as bright as when seen with the naked eyes.
    •  The human pupil becomes smaller in a bright situations, so you won't perceive images as dark with both 8x20 and 7x50 binoculars.

Why do both large-exit-pupil binoculars and small-exit-pupil binoculars provide the same bright images in bright conditions?

The human pupil normally opens about 2mm in daylight, and 7mm in the dark.
If you use binoculars with an exit pupil of over 2mm in daylight, you won't perceive dark images. Brightness will not vary whether you use binoculars with a 7mm or 2mm exit pupil.
On the other hand, if you use binoculars with a small exit pupil in the dark, the image will not appear as bright as when seen with the naked eyes.

Relative brightness

Relative brightness value is obtained by squaring the diameter of the exit pupil. The greater the relative brightness is, the brighter the image will be. With 8x42 binoculars, the brightness is (42÷8)2= 28.1. This means that if the magnification is the same, the larger the effective diameter of the objective lens, the brighter the image will be.

Do binoculars with the same exit pupil offer the same brightness?

No. Brightness may vary even if the exit pupil is the same. This is because the amount of light reaching the viewer's eyes varies according to the number of lens elements and quality of lens/prism coatings. Superior optical design and highquality coating greatly contribute to the brightness of binoculars. Brightness values specified in product brochures, etc. are theoretical ones calculated in the design process. Please note these factors when comparing actual brightness values.

Eye relief

Eye relief is the distance from the outer surface of the eyepiece lens to the position where the exit pupil is formed (eyepoint).
Looking through binoculars from the eyepoint, you can obtain the whole field of view without vignetting.
It is recommended for eyeglass wearers to use binoculars with a longer eye relief (high eyepoint).

Eye relief

For eyeglass wearers

Long-eye-relief binoculars
Short-eye-relief binoculars


Field of view

Real field of view

Real field of view is the angle of the visible field, seen without moving the binoculars, measured from the central point of the objective lens. The larger the value is, the wider the viewfield available. For example, binoculars with a wider field of view are advantageous for locating fast-moving wild birds within the viewfield. This also applies for finding small nebulas or a cluster of stars in astronomical observations.

Apparent field of view

Apparent field of view is the angle of the magnified field when you look through binoculars.
The larger the apparent field of view is, the wider the field of view you can see even at high magnifications.
With the conventional method used previously, the apparent field of view was calculated by multiplying the real field of view by the binocular magnification. (With this formula, apparent field of view wider than 65˚ is called wide field of view.)
After revision, Nikon's figures are now based on the ISO 14132-1:2002 standard, and obtained by the following formula:

tan ω' = Γ x tan ω
Apparent field of view:2ω'
Real field of view:2ω
Magnification:Γ

(With this formula, apparent field of view wider than 60° is called wide field of view.)

For example, the apparent field of view of 8x binoculars with a 7.0° real field of view is as follows:

  • 2ω’= 2 x tan-1 (Γ x tan ω)
    = 2 x tan-1 (8 x tan 3.5°)
    = 52.1°

Field of view at 1,000 meters

Field of view at 1,000 meters is the width of the visible area at a distance of 1,000 meters, which can be seen without moving the binoculars.
For example, with 8x42 7.0° binoculars:
Field of view at 1,000m = 2 x 1000m tan (7.0÷2) = 122m

Product Specification
Specifications

Magnification (x)
10
Objective diameter (mm)
42
Angular field of view (Real/degrees)
7.0
Angular field of view (Apparent/degrees)
62.9
Field of view at 1,000m (m)
122
Exit pupil (mm)
4.2
Relative brightness
17.6
Eye relief (mm)
15.7
Close focusing distance (m)
3.0
Length (mm)
150
Width (mm)
130
Depth (mm)
52
Weight (g)
575
Interpupillary distance adjustment (mm)
56-72
Type                  
Roof

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Nikon Prostaff P3 10x42

  • Brands Nikon
  • Product Code:Nikon Prostaff P3 10x42
  • Availability:In Stock
  • N$4,995.00