A Work Commenced December 9 2024.
Product: Svbony SA401 25x-75x 100 APO
Country of Manufacture: China
Clear Aperture: 100mm
Armouring: Forest Green Rubber
Magnification Range: 25x-75x
Field of View: 1.77 degrees @ 25x -0.92degrees @ 75x
Focal Length: 556.2mm
Focal Ratio: 5.6
Focuser: Single Speed, Helical
Coatings: Fully Multicoated
Objective Design: 4-Element Double ED APO
Prism Type: K9 Porro
Exit Pupil: 4mm@ 25x, 1.3mm@ 75x
Ability to use Interchangeable 1.25” Eyepieces:Yes
1.25” Eyepiece Adaptor: Yes
Waterproof: Yes IPX7
Nitrogen Purged: Yes
Weight: 2.9kg
Length: 458mm
Accessories: 1.25” eyepiece adaptor, SC001 imaging camera, scope protective jacket, IPhone adaptor, instruction manual, lens cleaning cloth
Price(UK): £779.99
Over the last few years I’ve watched spotting scopes grow in size. Just a few years back, birders and nature watchers routinely used 60-80mm scopes to study their targets at distance, but recently, a new breed of super big spotters have been released onto the sports optics market, with apertures of 95mm, 100mm and even a 115mm are now being routinely employed by enthusiasts who can now enjoy greater light gathering power and higher resolution images. Big spotting scopes employing ordinary crown & flint glass suffer badly from chromatic aberration at higher powers making them practically unusable at their highest magnification settings(60x or so), necessitating the need for extra low dispersion elements to reduce colour fringing, and increase image sharpness and contrast. But as the aperture increases whilst retaining the typical fast focal ratios(<F/6) required of spotting scopes, chromatic aberration becomes very aggressive indeed, requiring much more attention to detail. Many of these scopes have triplet objectives with one element employing fluorite crystal to stave off colour fringing around high-contrast targets. Fluorite is very expensive though, is very brittle and slightly water soluble, characteristics that reduce its durability in the long run. Thankfully, there are other, less costly ways of achieving much the same or better results, such as using two lower-grade ED elements in the objective design. Typically, these bigger triplet spotting scopes command prices upwards of £1400, while top European brands will usually set you back twice as much or more again.
In this review, I wish to showcase a new APO spotting scope by the Hong Kong-based company, Svbony, embodied in their new flagship line of premium spotting scopes, the SA401 series. Two models are available; the smaller 85mm and the 100mm showcased in this review. Furthermore, both retail for well under £1000.
First impressions:
Typical of Svbony, the SA401 100mm APO scope arrived in packaging I can only describe as immaculate. Double boxed, the instrument was sturdily positioned inside its white foam casing, together with various accessories, including a SV 402 1.25” eyepiece adapter, a 2 mega pixel SC001 imaging camera, and a black scope jacket to protect it from the elements. Let’s take a closer look at the instrument.
The magnesium alloy chassis of the SA401 100mm APO spotting scope is overlaid by a thick layer of forest green rubber armouring, with black extremities at the eyepiece and objective ends. The textured rubber single speed helical focuser is also finished in black. An attractive cherry-red ring positioned behind the retractable lens shade displays the essence of the SA401 design, employing two ED elements in its APO designation, and covering a magnification range of 25x to 75x.
The focused cone of light from the 4-element objective is reflected to the zoom eyepiece via a Porro prism using K9 optical glass(the optical equivalent of BK7) which is perfectly suitable for this F/5.6 instrument. In addition, K9 optical glass has a lower dispersion profile than BAK4, which helps a wider range of visible wavelengths to remain tightly focused before being magnified by the eyepiece.
Like their other spotting scopes, a large, round knob is located on the upper right of the chassis just ahead of the helical focuser. Once loosened, the built-in mounting bracket can be smoothly rotated through a full 360 degrees, which enables the user to achieve a comfortable viewing position irrespective of the location of the target.
The interior of the SA401 spotter is very clean and dust-free, as the photo below shows, with nicely machined baffles, and other blackened components to help reduce stray light and maximise image contrast.
To be Continued…….