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BinocularsFor Birders

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You are a person who enjoys watching birds and thisputs you in good company.

In the estimates of the United States Fish andWildlife Service, over 60 million North Americans have

discovered the pleasure and challenge of birding.

C hances are, you already owna pair of binoculars – a pair

you inherited or bought withoutmuch thought; a pair that hasserved, but maybe did not excel.

But now you are ready tomove up to quality optics...binoculars that will make it easyto get into those hyperkineticwarblers and treetop vireos.

You need binoculars that aresharp enough to resolve thedetails that separate look-alikeflycatchers and bright enoughto disclose the facial pattern ofan “olive backed" thrush stalkingthe shadows. In short you areready to buy a pair of “birdingbinoculars."

Won’t Just Any Binocular Do.Binoculars are the primary

tool for bird watching. Different“User Groups" (hunters,yachtsmen, backpackers,concert goers) use binocularsas an accessory to theiractivity or sport. But binocularsare not just an accessory tobirding.

Binoculars are theinstruments that definebirding – the functionalequivalent of the firstbaseman’s glove, themusician’s instrument, theplow in the hands of thefrontier farmer.

Every user group has its ownpeculiar needs and constraintsthat binocular manufacturerstranslate into binocular makesand models.

Hunters, for example, demandrugged, durable, optically precisebinoculars that perform welleven in the low light conditionsof dawn and dusk. Yachtsmen

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require optics that areimpervious to weather.Backpackers want optics thatare light and portable.

But birders demand all theseattributes and more. Forbinoculars to be birder worthy,they must not only be durableand precise, but alsoweatherproof and portable.They must focus fast and focusclose. They must offer agenerous field of view andprovide exceptional depth offield even at close quarters.This article has one objective:to give you the information youneed to choose true birderworthy binoculars and spottingscopes.

Forewarned is ForearmedThere are several things you

should know even before talkingto a salesperson.

FIRST – As a bird watcher,you represent the largest “usergroup" in the optics market.Over 30 percent of allbinoculars purchased are usedfor birding.

SECOND – The needs andconstraints of birding are wellknown to binocularmanufacturers, but they mightnot be known to the salesperson you deal with.

Chances are, after readingthis article, you will know muchmore about birding binocularsthan any non-birdingsalesperson you will meet. Don’tlet them confuse you.

THIRD – All equipment,including binoculars, is designedto compensate for a humanshort-coming. People shouldnever be forced to compensatefor their equipment.

If the binocular you areconsidering is flawed inperformance or design (i.e.,they do not focus closeenough…they do not fit yourhands…the ocular lensescannot be adjusted closeenough to offer a singleimage…) do not buy them! Ifyou do buy them, you will onlyreplace them later.

FOURTH – There are verycheap binoculars and veryexpensive binoculars. There arebinoculars that are good forbirding, and binoculars that arenot good for birding.

There are no good cheapbirding binoculars. It takesquality materials andsophisticated engineering tocraft birder worthy binoculars.Expect to pay a commensurateprice – three to four hundreddollars at least.

What Are Binoculars.Binoculars are twin barreled

telescopes whose barrels arealigned to fall on the samespot. They are superior to atelescope insofar as they canbe used with both eyes open –making long-term viewing easier.Since binoculars are usuallyhand held, they are also moreportable and faster to use thantelescopes.

Binoculars are divided intotwo basic design classes:

s Porro prism; ands Roof prism.

Porro prism or “traditionalbinoculars" are wide-bodied. Thebig lens in front (the objectivelenses) and the smaller one inthe back (the ocular lenses) areoffset – i.e., not aligned along avertical axis.

Roof prisms, which becamepopular in the late ’60s and’70s are longer and sleeker indesign, with the objective andocular lenses falling inalignment along the same tube.

Both designs haveadvantages anddisadvantages. Because Porroprism binoculars have fewerinternal “elements" (lenses andprisms) and more generoustolerance specs, they aregenerally brighter, lessexpensive to manufacture, andless expensive to repair in theevent of a mishap.

Roof prisms, though moreexpensive, also tend to be morerugged with elements morefirmly anchored within thebarrels. Many people also findRoof prism binoculars easier tohold steady for extendedperiods.

Binocular ShapeThe important thing about

binocular shape is how they feelin your hands.

If you grasp a pair ofbinoculars and bring them toyour eyes and your finger doesnot fall comfortably upon thefocus wheel, or if you have toshift your grip to move thefocus wheel, then thebinoculars are poorly designedor too large for your hands.Put them back on the shelf.

Likewise, if you bring thebinoculars up to your eyes butfind that you cannot draw theeyepieces close enough to offera single image, put them backon the shelf. The minimum“interpupillary distance"offered by some models issimply not close enough toaccommodate people withclosely-set eyes.

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Shape directly relates to howeasily and steadily binocularsmay be held, and this directlyaffects image quality.

“Mini" binoculars, favored bybackpackers because of theirreduced size and weight, offerlittle to anchor a shake-freegrip so birders generally avoidthem.

Large, bulky or “Marine"binoculars force users to holdtheir elbows high and widelyspaced, decreasing stabilityand increasing muscle fatigue.Birders avoid these, too.

Binocular WeightBinoculars are literally a

weight around your neck. Howmuch you want to bear is up toyou, but in general, 20-30 oz. isabout as much as most peoplecare to consider.

The elements contributing tothe overall weight in a pair ofbinoculars include:

s the optical elements;s the body; ands the outer covering.

High quality optics, made ofbarium crown glass (BAK-4),are denser and heavier thanoptics made of the cheaperboro-silicate glass (BK-7). Thequality of the image you see isdirectly related to the quality ofthe optics.

To reduce overall weight,quality binocular bodies arecast out of aluminum or ruggedspace age synthetics.

To help protect the internalelements many binoculars are“armored" – covered with shockabsorbing rubber orpolyurethane shell instead of a

leather-type or guttaperchacovering.

FocusingBirding demands binoculars

that focus quickly. Whenattention is diverted from aclose-at-hand warbler, to adistant, fast disappearinghawk, time spent spinning thefocus wheel to go the range offocus is, well, time spentspinning your wheels.

A binocular that can gofrom close focus to infinityquickly and smoothly isinvaluable in the birding arena.

Birding binoculars should becenter focusing binoculars. Thismeans that by moving a wellpositioned wheel, both barrelsof a binocular are adjustedquickly and simultaneously.

An individual eyepieceadjustment ring (or knob) isavailable to compensate forthe small differences thatexist between an individual’seyes. It is set once – thennever again.

Some military or marinebinoculars offer individualeyepiece focusing – a systemthat employs adjustable ringsthat encircle both ocularlenses. This system is slow,cumbersome, and therefore, illsuited for birding.

Some binoculars offer leversinstead of wheels for “quickfocus." These are appealing intheory but in fact require atwo-handed grip and a bit ofdickering to get a sharp image.They also tend to not be verydurable.

Some manufacturers alsooffer permanent focus or non-

focusing binoculars. These wouldbe fine, if birds neverapproached closer than 50 feet– which is about as close aspermanent focusing binocularscan offer a clear image.

But as birders know, birds doappear closer than 50 feet. Infact, sometimes – in cattailmarsh, dense woodlands, ortropical forest, a bird might beno more than ten feet away,and because of poor light orobstructing vegetation, anidentification cannot be madewith the naked eye.

At times like these abinocular that offers super-close focus may make thedifference between a Life Birdor a shoulder shrug – which isto say, all the difference in theworld.

Birding binoculars should beable to focus down to 15 feet.Binoculars that offer a closefocus down to nine or ten feetare prized.

If you do a great deal ofwoodland birding, or watchbirders coming to your feedersat very close quarters, closefocusing binoculars are a must.

MagnificationBinoculars come in different

powers designated by the firstnumber of the binomial legendetched on all binoculars(examples: 8x30, 7x42, 10x42).

The second number refers tothe diameter of the objectivelens in millimeters and will bediscussed in the section dealingwith “Light and Brightness."

Simply put, a 8x binocular(eight power) makes distantobjects appear eight times

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closer than they really are; a10x binocular makes the objectappear closer still – ten timescloser.

The tendency is to believethat bigger is better – that themore “power" a binocular has,the better it will perform. Thisis not necessarily so and thereare several reasons for this.

First, although highermagnification will increase thesize of a distant bird andenhances the details that willbe seen, increasedmagnification also magnifiesthe effects of hand shake andheart beat.

The image may well be biggerbut details, as measured byimage perception, will remainessentially the same.

Greater magnification alsoresults in a smaller field of view,a darker image, and a shallowerdepth of field – all of whichdirectly affect binocularperformance.

Almost all active birders usebinoculars that offer between 7xand 10x. What magnification youchoose hinges on a number ofconsiderations.

In general, lower magnificationis to your advantage if:

s You are a beginning birder,unpracticed at locatingbirds with binoculars;

s You are a birder havingdifficulty holding highermagnifications steady;

s Much of your birding isconducted at closequarters – in woodlands orrain forests, or from thedeck of a moving boat;

s You are a highly skilled birdermore interested in speedthan in seeing “field marks"of birds you recognize bytheir JIZ (general impressionand shape).

Ten power binoculars get thenod if:

s Your hands are steady;

s Most of your birding isconducted over greatdistance and open spaces;

s You do not commonly includea spotting scope in youroptical arsenal.

If you are still undecidedbetween 7x or 10x binoculars,consider a compromise – likean 8x but NEVER BUY A ZOOMBINOCULAR! They are opticallyinferior and even at the lowestmagnification, offer acomparatively limited field ofview.

If you look at the optic linesoffered by the finest opticalcompanies or if you look at theinstruments in the hands of thefinest field birders, you will neversee a zoom binocular. Thisshould send a clear message tothe discerning consumer.

Light and BrightnessOnce – and not long ago; and

not without reason – much was

Purchase Quality Binoculars

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made about binoculars andbrightness and light loss.Guides to purchasing opticsexpounded upon the mysteriesof the “twilight factor," and“relative brightness," and“relative light efficiency." Salespeople who know little aboutbinoculars except, perhaps, howto read charts still expoundupon these mysteries.

Certainly a bright image,offering sharp contrast andaccurate color rendition isimportant to birders – in fact,it is essential. The fact of thematter is that since the adventof coated lenses…and multi-coated lenses...and phasecoated Roof prisms...all the oldrules governing glass and lighthave been bent.

If you are willing to pay theprice for quality binoculars,you are virtually assured ofowning binoculars that offersuperior brightness.

The problem used to be this.Every time light strikes polishedglass (like a lens; like a prism)5% of it is lost, reflected away.In every binocular there are 10-16 glass surfaces whosecumulative loss of light equaledabout 50%. The net result wasa dark image.

In partial compensation,binocular manufacturers couldincrease the size of theobjective lens. The size of theobjective lens is measured inmillimeters and appears as thesecond number of the legendstamped on binoculars(example: 7x42, 8x30, 10x50).

Larger objective lenses allowmore light to enter thebinocular, increasing thediameter of the shaft of light

that exits the binocular to fallupon the human eye.

This shaft of light, seen asthe bright dot swimming in thecenter of the ocular lens iscalled the “exit pupil" and isstill an importantconsideration when buyingoptics. Here’s why.

The human eye has a pupil,too – one that opens andcontracts in response to lightconditions. In bright light it canexpand to about 7 mm(depending on your age), thusestablishing the functional limitof the binocular’s exit pupil –because any light fallingoutside the maximum limit ofthe human eye serves fornothing.

Beginning in World War II, itwas discovered that a coatingof reflection reducing material(like magnesium fluoride)applied to the surface of glasscould reduce light loss causedby reflection from 5% to almost1%. This coating appears as ablue, or purple, or green glazeon the lenses.

Later it was discovered thatby applying multiple, thincoatings instead of a singlecoating, light loss could befurther reduced to a merefraction of 1%.

Recently, severalmanufacturers of superiorquality Roof prism binocularshave begun coating the “Roofprism" with a material thatcompensates for the modestwave length shift inherent inthe Roof prism design with theresult that “phase-corrected"Roof prisms offer the samesharp image contrast found inPorro prism binoculars.

The important considerationwhen buying binoculars is tomake sure the optics are “fullycoated" or, better still “fullymulti-coated." The operativeword is “fully" because thismeans that all air to glasssurfaces both inside thebinocular and out have beentreated to reduce light loss.

Different manufacturers usedifferent, patented names todistinguish their coatings. Theimportant thing is to be surethat all glass surfaces, insideand out, are single or “multi-coated" to reduce light loss.

The process used to coatbinoculars lenses is exactingand costly. It accounts formuch of the price differencebetween quality binoculars andless expensive binoculars. But acommensurate price can also beyour assurance that your arebuying binoculars that arebright and sharp enough toperform in the field.

Field of Viewand Depth of Field

Field of view is the measure ofthe distance from one side of abinocular’s image to the otheras seen through a stationarybinocular.

This measurement, eitherinscribed on the binocular orincluded in the accompanyingliterature, may be designated indegrees of arc (ex: 6, 7); feet at1,000 yards (ex: 415 feet at1,000 yards); or meters at1,000 meters.

However the measurement isnoted, a wide field – one thatoffers no less than 6 degreesof arc (or a minimum of 300feet at 1,000 yards) isessential to birding.

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A wide field makes it easierto pick up and identify fastflying birds. It makes it possibleto scan a sky, an ocean, or anopen marsh quickly. It’s alsoeasier to locate birds at closequarters in a maze ofbranches.

Birding binoculars shouldalso offer good depth of field –a sharp, adjustment-freeimage from near to far. Agenerous depth of field assistswhen trying to locate a close-at-hand bird in a maze ofbranches. A generous depth offield mitigates the need tomake focus adjustments everytime a bird moves a littlecloser or a little farther away.

Both field of view and depthof field are closely related tomagnification. In general,binoculars with lowermagnifications offer greaterdepth of field, and a wider fieldof view than binoculars withhigher magnification.

Eye ReliefVery closely related to field of

view, eye relief refers to thedistance between the ocularlens and the human eye. Thisdistance is measured inmillimeters.

Eye relief is a veryimportant consideration forbirders who use eyeglasses inthe field and who do notremove their eyeglasses whenfitting binoculars to theireyes.

Because the eyes of eyeglasswearers are already set 10-15mm behind a glass barrier, theydemand a very “high" eye point– a binocular that offers aminimum of 15 mm of eye relief.

With rubber eyecups rolled downor otherwise retracted,eyeglass wearers can enjoy thesame wide field enjoyed by non-eyeglass wearers.

NOTE: Just because a pair ofbinoculars comes with rubbereyecups does not mean theyoffer good or even adequate eyerelief for eyeglass wearers. Thetest is in the length of theactual eye relief.

Weather Resistance/Water Proof

Birding is an activityconducted outside, and fromthe moment a birder takes hisor her binoculars outside, theoutside is trying to get insidethose binoculars.

In general “Internal Focusing"binoculars are better sealedagainst dust, pollen, andmoisture than “externalfocusing" binoculars. To tellthe difference, move the focuswheel and see whether or notthe ocular bridge moves.

A very few superior binocularsare waterproof (not “waterresistant," not “weatherresistant," not “splash proof").They are waterproof – able towithstand complete immersionand remain dry inside. This is adifficult (and expensive boast)and binoculars that really arewaterproof/submersible willcertainly tout this.

You need not bird regularly inpouring rain to appreciate thebenefits of well built, well sealedoptics.

The day you jump from yourair conditioned car into asteamy Florida afternoon andtrain your now completely

fogged binoculars upon theswallow-tailed kite soaringoverhead will make you aconvert.

Other Important ConsiderationsWhether you are a World

Series of Birding combatant, arock climbing hawk watcher, ora casual backyard birder who ismeticulously careful withequipment – accidents dohappen. All birding binocularsshould be able to shrug off theoccasional bump and ding.

Superior binoculars areimpervious to airline baggagehandlers, children, andtumbles onto pavementprecipitated by a combinationof motion, gravity, and a fallto the roadway after beingleft on the roof of a car.

Well constructed, well sealed,armored binoculars offeranother advantage. They needno special care – they don’teven need to be returned to acase after use! Hang them upon the hook by the back door.Put them under the front seatof the car. They are there whenyou need them. Ready at amoment’s notice without havingto run to the closet...and grabthe box from it’s place on thetop shelf (out of the reach ofthe kids)...and open thecase...and remove thebinoculars...and extract theplastic plugs that protect thelenses...and run back to thekitchen window...to study thevibrating branch where the bird(that just left) had beenperched.

Lens protection is important,so most manufacturers ofquality birding binocularsinclude custom fitted rain

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guards with their opticspackage. Rain guards keepthings like rain drops, saltspray, sandwich drippings, andhot breath from obscuringoptics in the field. They alsokeep dust off lenses when thebinoculars are not in use. Somebinoculars also come withprotective cups for theobjective lens.

Binoculars should come withdurable, supple, and adjustableneck straps. Leather straps arechic, but crack and rot undernormal field use.

Plastic straps loose theirsuppleness in cold weather andwill loop when binoculars areraised – invariably fallingdirectly between the ocular lensand your eye.

Most quality binoculars nowcome with straps made ofbraided nylon. Wider strapshelp distribute weight evenly,saving wear and tear on abirder’s neck.

Speaking of wear and tear,perfection is an ideal thatoptics manufacturers strive for.Filling the gap betweentechnical precision and idealperfection is the manufacturers

equipment warranty. Qualityoptics come with a warrantythat covers materials andworkmanship.

Again, a very few superioroptics offer lifetime warrantiesto the original owner – aspecial bonus for those whopurchase optics designed andbuilt to last a lifetime.

Spotting ScopesIn time, after the birds of

woodland and field have beenmastered and savored, manybirders feel compelled to reachfor the horizon. They turn theiridentification skills uponmigrating hawks, winteringseabirds, or feeding shorebirds.

This kind of birding involvescareful study over greatdistances for extendedperiods, and in this arena, aspotting scope is ideal.

Spotting scopes rest upon atripod, a shoulder stock, orspecially designed windowmount. Thus stabilized, theymake higher magnificationpossible, bringing birds on thehorizon within reach. Popularpowers include 20x, 30x, 40xand 60x.

Zoom eyepieces are popularand do not, as a rule, sufferthe short-comings inherent inzoom binoculars. In fact, a fewspotting scopes with zoomeyepieces offer exceptionaloptical performance.

Like binoculars, spottingscopes come in a range ofquality and price and also, likebinoculars, you get what youpay for.

The Bottom LineBirding is an activity that

offers challenge, excitement,and a lifetime of pleasure. Thebetter your optics, the lessfrustration you will know andmore pleasure you will get outof birding.

When buying binoculars(and spotting scopes), therule of thumb is simple. Buythe best binoculars you canpossibly afford and buy themas soon as you can affordthem.

If you can’t immediatelyafford the quality binocularsyou want, tolerate the onesyou have or borrow a pair froma friend. Save for the opticsyou really want.

If you settle for less, you willonly regret your half-steppurchase until the day youreplace them with thebinoculars or spotting scopethat you really wanted allalong.

Good Birding!

WindStar Wildlife Institute is anational, non-profit, conservationorganization whose mission is to

help individuals and familiesestablish or improve the wildlife

habitat on their properties.

For more information or for thename of a Master Wildlife

Habitat Naturalist in your area,please contact:

WindStar Wildlife Institute

E-mail: wildlife@windstar.orghttp://www.windstar.org

About the Author...Pete Dunne, of the New JerseyAudubon Society, is one ofbirdings better known figures andauthorities on the optical needsof bird watchers. He is author ofThe Feather Quest, Tales of a LowRent Birder, and Hawks in Flight.His regular columns appear inAmerican Birds, Birding, andLiving Bird. He and wife, Linda, livenear Cape May, New Jersey.