How to Buy a Monocular on eBay

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How to Buy a Monocular on eBay

Buying items on eBay is easy to do. Choosing a monocular from the range offered in its extensive listings is the first step. The purchase might be driven by trying to find the best deal, the best product, or the fastest dispatch time. All three criteria are possibilities and, with some research, are attainable in a single purchase.
With such a range of instruments regarded as monoculars, first make sure of the type required so that when conducting a search there is a better chance of finding a match.


Features Checklist


The first number on a model description. Does it meet the requirements of the job?


Objective Lens Diameter

The second number on a model description. Will the diameter of the lens allow sufficient light for viewing? How much extra weight will a larger lens contribute to the scope?


Eye relief

The distance between the ocular lens and the rim of the eyepiece. Is it comfortable? Does it bring the eye close enough to the lens when wearing glasses?


Size of eyepiece

The dimensions of the viewing hole at the ocular lens end. Is it a comfortable fit? Does it leak stray peripheral light because it is too big?


Field of View

The visible area limit of the monocular when looking through it. Is it large enough for function?


Adjustable eyecup

For comfort and enabling close proximity to the ocular lens. Usually a rubber cover that can be rolled up or down to shorten the distance of eye relief.


Close Focus

The distance required for near observation with magnification such as blossom detail on flowers. For close work, a shorter focus distance is preferable.


Dual Focus

The facility on a scope to adjust focus from a knob situated on the main body and to fine focus from a wheel at the eyepiece.


Optical Coating

Coated lenses offer a variety of benefits that reduce glare and haze. Good-quality optical glass will have multi-coating. Does the scope have ED glass (Extra-low Dispersion) lenses which prevent chromatic aberration or secondary spectrum?


Prism System

The arrangement of prisms within a monocular or scope will determine how the image is presented. Porro – dog leg prism, Dach, Morita or Bak4 – roof prism are the usual systems.


Fixing Point for Tripod

A stabilised instrument will capture a clearer image and eliminate the noise created by wind movement or hand shake.


Exit Pupil Size

The largest a human pupil can open is 7mm. On a viewing instrument, anything larger than this will not improve the eye's ability to receive the light available through its lens.


Ergonomic Design

Anti-slip grip and moulding to accommodate hand position perhaps in rubber or similar material. Armour protection.

Physical  Dimensions



The distance from objective lens (bottom) to eyepiece (top).


Barrel Diameter

This may not always be circular as some models feature shoulder stacked focussing a separate tracker or range finder barrel mounted on the main barrel.



The weight of a monocular on its own. Consider also additional accessories that might require carrying.

Different Types of Monoculars

Monoculars offer a single eyepiece instrument for viewing distant objects. Akin to mini telescopes, they differ in the final image alignment produced by a correction prism, and to suit outdoor use, they feature waterproofing that a telescope, an indoor instrument, does not. Hikers, hunters, campers, and nature watchers are among many who opt for monoculars over binoculars. Theatre goers or gallery visitors find a small monocular indispensable for closer views. The single barrel reduces weight, and some designs incorporate one-handed focusing for easy use. Weighing only 2oz, models as small as 75mm x 25mm have an optional microscope attachment for extreme magnification suitable for close observational detail.
Knowing the purpose of the product helps limit the number of results offered by eBay when buying monoculars as keywords will return a best match to a searched item.

What the Figures Mean

Monoculars are sold in different sizes but the numbers beside the model name refer to magnification power and the diameter of the objective lens. The first figure may go as high as three digits for powerful magnification used in star spotting. The second figure shows how wide the lens at the end of the scope is and how much light it can receive. Hand held monoculars seldom exceed a diameter of 50mm though larger sizes are available for monoculars used more as telescopes and mounted on tripods. The wider the objective lens, the better quality the field of view. Better-quality optical glass ensures comparatively sharper images once magnification is increased. Magnification always makes an image appear dimmer even though it brings it closer to view. When buying a monocular on eBay, check the box on the listings page for the preferred magnification.

Comparison Example for Eyepiece and Magnification

Eyepiece Type

Wide, fixed, low magnification. Ideal for observation of near and wide-moving subjects.

Wide, fixed, high magnification. Ideal for observation of distant subjects, fixed-point observation, and detail.

  1. Step-free low to high adjustable magnification.

Objective lens effective diameter








Field of view when using 85mm effective diameter of the objective lens – using a bird as a subject for comparison

Balanced composition includes a bird on a branch, tail feathers same length as body with diffused background. Field of view appearance at 1,000m is 58m – wider than the zoom equivalent.

The bird's face, beak, and upper chest fill most of the composition close enough to see eye detail.

Balanced composition includes a bird on a branch, tail feathers same length as body just fitted in and with less background.
Field of view appearance at 1,000m is 38m – tighter than the fixed (lower) magnification eyepiece.
At 60x the bird's face, beak, and upper chest fill most of the composition but without as much detail as the fixed (higher) magnification.

Fixed magnification provides superior performance for digiscoping and prevents vignetting.

Alternative Calculations

When reading the product description posted by a seller, there are some other things to understand. Some manufacturers label their models using focal length and magnification as the descriptors. Longer focal length tends to produce better-quality views. A scope might be described as 600 x 60 (600mm long with an objective lens 60mm wide), and the eyepiece used with it may have a focal length of 16mm. The calculation to determine magnification value is worked out by dividing the scope’s focal length by the eyepiece focal length; 600/16 = 37.5x.
Monoculars used as spotting scopes with variable magnification zoom ability are described with the magnification range expressed as the minimum-maximum in front of the objective lens size. For example, a scope offering a magnification range between 20x and 60x on an instrument with a 60mm objective lens would appear as 20-60x60.
Monoculars for Sportsmen, Sportswomen, and Spectators

Although sportsmen and sportswomen might desire monoculars for their sport, on eBay the best chance of finding the item is in the Camera & Photography section rather than Sports & Leisure. This is due to the sophistication of the lenses and prisms fitted in the eyeglasses.
Golfers make use of monoculars as range finders to calculate pin distance or to follow the ball’s flight path and to find it if it has fallen into the rough. Marksmen need monoculars when shooting at target ranges over distances where bullet holes are impossible to see with the naked eye. Magnification is required to judge the position of the entry hole. The feedback allows the marksman to tweak the gun sights for aim adjustment and better results.
Safety is an issue for alpine skiers. Individuals, or instructors responsible for leading groups, utilise monoculars to check off piste routes are clear of hazards ahead which help them choose a safe path. Spectators at any sport where the participants disappear into the distance such as cross country events for bikes, rally cars or equestrian events appreciate being able to follow the action with monoculars. It might be worthwhile refining a search when buying monoculars on eBay to include ergonomic grip or armour-grip for a comfortable hold over long periods.
As an alternative or accompaniment to a pair of binoculars, monoculars are often used as field glasses by naturalists, bird watchers, hunters and conservationists. Underwater photography and marine observation use monoculars and sea rescue teams also utilise the instrument, often with a night vision attachment to assist searches in poor visibility.
Include search keywords relevant to a sport to see any recommendations on eBay that might offer the best fit for that activity.

Monocular Photography – Digiscopy

Another reason why monoculars are found in Cameras & Photography on eBay is the growing popularity of digiscopy. Hooking up a camera to a monocular lens can produce amazing photographs from the observed magnification. Birders and astronomers keen on capturing unique shots displaying fine detail perform digiscopy with the monocular scope attached to a camera mounted on a tripod. Stabilising the equipment prevents image blur or noise and allows the photographer to use slower exposure settings without any disturbance to the view.

Making a Monocular Versatile

Several accessories will transform a monocular scope. Buying a monocular on eBay might prompt a purchase of accessories to augment the monocular and the experience of using it. There might be Buy it Now options or there could be a private seller who has the item up for sale. Whichever way an offer is made, shoppers on eBay can secure terrific bargains.
Adding a diagonal lens to right an image from upside down and a moon filter or light filter allows better views of astronomical subjects. Adapters, tripods and digital eyepieces can link to a computer via a USB connector. An image may be photographed and stored or viewed and shared on screen without loss of resolution.
In the field, a spotting scope with an eyepiece angled at 45 degrees on the ocular lens provides greater comfort when sitting or sharing the view with other users. Other models for target shooting, sightseeing or bird watching are offered as straight barrels.
How to Find a Monocular on eBay

Read through the menu on eBay’s home page. Use the cursor to roll over the Electronics category, and select Cameras & Photography. On the new page choose Telescopes & Binoculars and when yet another new page appears, choose Binoculars & Monoculars to search for the item which best suits requirements. Listed new every day, there are famous brand names and private sellers with items for sale side by side in auctions, Buy It Now, and Best Offer deals.


Read around to be able to make an informed choice about items, to compare prices, and discover how well a product performs in the field. A little research will make decisions easier to reach and searches easier to refine on eBay.

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