BinocularsCompact BinocularsMarineMonocularsFIELDscopes & EyepiecesDigiscopingTripods & MountsAccessoriesMagnifiers

Chooser GuidesDownloadsVideos

Product ReviewsProduct RegistrationWarranty InformationOrder a Product GuideSign up for News

Partnerships & ProgramS


Opticron uk website







GS 665 Fieldscopes
GS 665 GA ED

Discontinued October 2014
Listings for eyepieces and accessories are updated to reflect current models.

Specifications & Pricing I Eyepieces I Cases I Telephotography I Photo Gallery

GA 665 GA ED

Introduced in response to demand for high quality lightweight waterproof spottingscopes the Opticron GS 665 GA ED fieldscope sets the standard for people wanting to take-out and walk-about with their spottingscope whether for birdwatching or general wildlife observation. Available in straight-through or 45°, the fieldscopes are designed and manufactured to meet the three main requirements demanded by today's active telescope user: high-end optical performance, usability and reliability.

'High end' optical performance and value
The GS 665 GA ED fieldscope uses a 66.5mm diameter objective lens without any noticeable gain in size or weight over a 65mm. With a 5% more light entering the telescope, more light is emitted, resulting in brighter images compared to a standard 65mm model. 100% designed and manufactured in Japan using high quality glass and other materials, each GS 665 GA ED fieldscope produces high resolution images with minimal edge distortion and accurate color reproduction.

The GS 665 GA ED fieldscope is designed to provide class winning optical performance seamlessly in even pretty harsh conditions. Protected by full body natural rubber armor, the centrally positioned focusing wheel allows easy access for both right and left handed users and is rubber covered to deliver a positive feel with or without gloves. The focusing system is designed to allow adjustment from infinity to 50 yards in just a 270° turn with close focus set at 13ft. Housed within the same mechanism is a 9:1 ratio focus adjuster, providing greater focusing accuracy at top end magnifications.

More often than not, telescopes need to be tripod mounted for image stability so any weight saving is crucial. Constructed to be as light as possible, the GS 665 GA ED weighs just 37oz (w/o eyepiece) and as a result can be used comfortably on a standard ‘non fluid’ panhead often found on Clamps or Travel Tripods. In addition each unit is fitted with a -/+ 90° rotating die-cast alloy tripod sleeve with 45° incremental 'stops'. This feature enables the scope to rotate around its’ central axis for accurate positioning when mounted to a bipod or on a clamp in a Hide or Blind. To avoid problems of reflected light on the objective lens in bright sunlight models are fitted with a retractable lens hood with integrated objective lens cover.

Having access to full a range of eyepieces is also important and the GS 665 GA ED fieldscope is fully compatible with Opticron SDL and HDF T eyepieces.

Extensively tested for continuous trouble free use in varying temperatures, the models are fully nitrogen gas filled waterproof and come with the assurance of a Limited Lifetime Warranty.


Specifications & Pricing

Specifications 665 ED 665 ED/45
Objective (mm)
Close Focus (ft/m)
Length (in/mm)
Weight (oz/g)
12.5 / 3.8
12.8 / 326
37.0 / 1049
12.5 / 3.8
12.8 / 326
37.1 / 1053





*MSRP $ Oct 2014




A wide range of eyepieces are available for Opticron fieldscopes. Choosing the best one is often confusing but making the right choice will depend on price and application. It is important you remember the eyepiece is an integral part of the system and choosing a lower quality lens will affect overall image quality.

SDL v3 Eyepiece
Designed with a 3x range for maximum versatility, the eyepiece delivers superior cross-field definition and exceptional viewing comfort with or without glasses. Waterproof and fitted with a 4-stage twist-type eyecup. Supplied in soft padded case. Limited Lifetime Warranty.

SDL v3 Zoom  
Code 41270
Eye relief (mm) 
Eye lens dia (mm)
Length (in/mm)
Weight (oz/g)
2.7 / 68
9.2 / 260



HDF T Eyepieces
High definition eyepieces with long eye relief. Fixed magnification models are wide angle. Twist type retractable eyecup to enable precise eye to eyepiece distance adjustment. Limited Lifetime Warranty.

40810 eyepiece
40831 eyepiece
40862 eyepiece  
40810E 40831E 40862E  
Code 40810G 40831G 40862G
Eye relief (mm) 
Eye lens dia (mm)
Length (in/mm)
Weight (oz/g)
1.6 / 40
5.3 / 151
2.0 / 50
5.3 / 150
3.0 / 76
7.3 / 206



Fieldscope CasesWP Case Black

Stay-on-the-Scope Waterproof in Black
Water resistant multi-layer padded cases individually designed to fit each model. Protects instrument while fitted to a tripod and in use. Includes removable end caps and adjustable carry strap.


WP Case in use


Code Model MSRP $
GS 665 GA (65) Black
GS 665 GA / 45 (66) Black











Wildlife montage

Telephotography is easier than ever to enjoy using Opticron spottingscopes in combination with a wide range of imaging devices. CLICK HERE for more information on telephotography with GS 665 GA ED fieldscopes.


© Opticron 2020 I Privacy & Cookies