Spotting Scopes Terminology

Spotting scopes are used when more magnification is needed or wanted than binoculars provide. Spotting scopes are used widely for birding, viewing wildlife and landscapes and other objects at a great distance. Much of the terminology and technical specifications specific to spotting scopes are similar to binoculars. For example, a 20-60×82 spotting scope has a zoom magnification range of 20-60x (20 to 60 times larger than the size of an image as would be seen by the naked eye) with a front lens diameter of 82mm.

The significant increased magnification of spotting scopes can take you well beyond the capabilities of conventional binoculars. That said, two factors, the atmosphere and the optical system of the spotting scope, should be kept in mind. Heavy air, dust, humidity, glare and wind and air currents during the day can all reduce image quality and the greater the magnification, the more drastic the reduction in image quality will be. Few locations allow you to use more than 60-80x during the day, so most spotting scopes stop at 60x. The optical system of a spotting scope will impact magnification also.  As magnification is increased, some decrease in image quality will result, no matter the model. In this key area, as the old saying goes…you get what you pay for.  So yes, if you want a spotting scope that is as clear and sharp at 60x magnification as it is at 20x, then expect to pay more. Keep in mind though that most spotting scopes are used at lower magnifications, usually around 30x-40x. This is more than enough for most applications and all but the least expensive and cheapest model will produce reasonable images in this magnification range.

Objective Diameter

Assuming that you are comparing two models of similar quality, the larger the objective lens, the more detail you can see and the better image quality your scope will deliver, especially at higher magnifications. However, a large lens of mediocre quality, no matter how large, will never equal the performance of a smaller, quality lens. If you aren’t sure, opt for quality, not size.

Close Focus

Although not an absolute necessity, a spotting scope with a close focus of 20 ft or less can be useful, especially if you plan to use a spotting scope with a camera.

Eye Relief

As with binoculars, this is the distance your eye can be from the eyepiece and still see the entire field of view. As a general rule, you will need at least 14mm of eye relief to see the entire field of view with eyeglasses and people with thick glass lenses in their eyeglasses will probably need more.

Waterproofing

While not a necessity, a waterproof scope is terrific to have. The seals in a waterproof model also prevent the infiltration of dust and dirt and therefore add to the lifespan of the spotting scope.

Tripods

Due to its high magnification, handholding a spotting scope and expecting to maintain a clear, non-blurry image is virtually impossible. A spotting scope requires that it be supported to keep it steady. You may be able to sneak by at lower magnifications with a monopod or shoulder stock, but above 40x, you must use a tripod. And the larger and heavier the scope, the larger and heavier the tripod should be. As all spotting scopes are threaded in the same fashion as a camera and therefore should fit on any standard camera or video tripod, unless you prefer, you will not need to purchase a special tripod for your spotting scope.

Best Spotting Scopes for Birding

Most agree that the best magnification range for birding with a spotting scope is 20-40x. Much higher than 40x and the field of view is too narrow to be practical, with the added drawback of a dimmer image. Keep in mind that problems such as heat waves will increase at higher magnifications. If you do a lot of dawn or twilight bird observation, or if your area is often overcast and dim, a wider objective lens will give you a better image.  So you will  want to choose a lens of 77-82mm. However, a larger objective lens also translates to increased size and weight. Birders who are out mostly during the day and don’t relish the thought of carrying a heavier instrument will want to consider an objective lens size of 60-65mm.

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Most of us begin birding with a field guide and a pair of binoculars.  Yet, we eventually realize that certain situations demand our acquisition of a spotting scope.  It may be that we find ourselves at the wetlands and can not quite tell if we are looking at a White Faced or Glossy Ibis.  Or, we spot a raptor across the canyon and can not say if it is a Red Tail or some other hawk.  Or, maybe, we just would like a better look at the Black Throated Green Warbler high up in the oaks.

Your advancement in birding does not mean you are becoming an elitist.  Your expertise is growing and should be cause for celebration.  Owning a spotting scope doesn’t make you an elitist either.  In fact, many manufacturers have improved their processes to accomplish advances in construction and image quality while making their product more affordable.   The spotting scope is now considered as essential as the binoculars.

There are many elements in the choice of a scope.  Many are personal preferences.  One such is whether to buy a scope that is straight through (ST) or angular (AN) sighted.  It is probably easier to find and focus on some distant bird using the ST configuration.  With practice, one can adjust to an AN scope and become just as proficient.  However, if you find that you are often in a group and sharing a scope the AN may be the better choice.  You can set the height to the shortest person in the group and everyone can easily view whatever bird is the subject of inquiry.

Light gathering ability is a major consideration in a scope.  Generally, the larger the objective lens the greater the ability to gather light.  An 80 mm objective gathers more light than a 60 mm lens.   However, with a larger lens also comes added weight and cost.  For most of us, and in most circumstances, objective lenses in the 60 to 65 mm range are quite adequate.

The eyepiece, or ocular, can be fixed or variable.  A 20x ocular is good for fixed eyepieces, but variable magnification are either 15x-45x or 20x-60x.  The lower magnification on the variable ocular is used to locate and focus the bird while the greater magnifications can be zoomed in to gain detail for a sure identification.

Eventually, one has to make a decision as to what amount to spend.  For those whose budget is limited the Cornell Laboratory Scope Quest 2008 becomes an excellent source of information and advice. Ken Rosenberg organized this event and compiled data on a number of scopes.  In this, the Stokes Sandpiper Scope did quite well.  Ken writes, “An even nicer surprise was the Vortex Stokes Sandpiper, which at $359 or less could be the best buy of any model we tested.  This small, lightweight scope is fully waterproof, works well with eyeglasses, and provides an image nearly as nice up to 45x as the more expensive [models].”  

Considering image quality, ease of transport, magnifications, objective lens size and, of course, cost, it all comes down to what fits your personal needs and preferences.  Once you have made your choice, enjoy it to the fullest.

As a both a birding and sports optics enthusiast, I was pretty excited to come home to see the June edition of Birdwatchers Digest in the mailbox. When I opened up the magazine I was even more excited when I noticed there were ten pages of the magazine dedicated to reviewing and evaluating “Mid Priced Birding Scopes”.  The test was administered by Diane and Michael Porter, operators of the website, birwatchers.com.  Any person or birder who frequently visits birdwatchers.com knows that Diane and Michael Porter are well respected in the birding community for their knowledge, passion for birding, and integrity. For me, this meant that the results of the review just had to be completely authentic even before I read them.  

What really jumped out at me was the fact that ‘mid-priced’ scopes were being reviewed. Mid-priced scopes per this article/review ranged anywhere from $100 all the way up to $899, meaning that I would generally be willing to pay for many of the scopes being evaluated. Personally, when I think of mid-priced scopes, I think the range is anywhere from $200 to $600. But the point here is that the high priced birding scopes were out of the discussion. Yes!! Anyone who’s been a birder for even a short while knows that birding scopes made by high-end manufacturers such as Zeiss and Swarovski can run you $2,000 or more. While the optics performance of these scopes are certainly superior to most brands, they are simply out of my price league

The mid-priced scopes review was broken into three categories by size, each containing about three to five products each. You have your 50mm sub-compacts, your 60-70mm compacts, and your full size 80mm scopes.  Scores from 1 to 5 were given for Resolution, Image Quality, Focus Knob, and Ergonomics. The highest combined average score were winners in their respective size categories.  The $700 Nikon Fieldscope ED50 blew away the subcompact competition; while the $899 Pentax PF 65 EDA II 20-60×65mm also won by a wide margin in the compact category. No surprises there as both contests were won by the most expensive scope in the category. However, there was a pleasant surprise winner in the full-size 80mm scope category: the $434 Alpen #788 20-60×80mm won by a wide margin over both the $500 Bushnell Legend Ultra HD and the $750 Vortex Skyline! Being the sports fan that I am, I would almost call this a major upset.

As an avid birder with a limited budget, seeing Alpen win was very satisfying, almost vindicating.  I will admit that I am an Alpen fan and have purchased optics products from Alpen before. But how could anyone not be impressed with what Alpen has done in the sport optics market after being in business only 11 years? Anytime a ‘David’ beats a ‘Goliath’(or in this case two ‘Goliaths’), whether it be on a playing field or in any other competition, it is human nature to be impressed with the accomplishment. In this case I obviously liken ‘David’ with Alpen while Bushnell and Vortex are ‘Goliaths’. Maybe the reason l like reading product reviews so much is that there is always a good chance that the ‘little’ guy can actually win because the playing field is usually completely fair.

This post was created by Vincent  Saponar, owner and operator of OneSourceOptics.com. If you are interested in the Alpen #788 Birding Scope, or -other quality sports optics equipment; please visit us at http://www.onesourceoptics.com