Rifl Escopes – P. 12 - ExpertVoice
THE BASICS OF OPTICSQUALITY p.4 SPECIFICATIONS p. 6 TRADE-OFFS p.10For hundreds of years, people have used optics toenhance vision, as well as optimize effectivenessof shooting equipment. Whether glassing up that bigbuck, taking aim, or simply observing the natural world,great optics make great experiences. Optics can bevery task-specific. For that reason, we want to makesure you’re armed with enough information to choosethe right tool for the job. So come on in and let’s talkoptics.For specific information, see page references below.Riflescopes – p. 122Vortex Optics Binoculars – p. 24Vortex Optics at www.vortexoptics.com Spotting Scopes – p. 323
OPTICAL GLASSQuality optics use dense optical glass that is painstakinglydesigned, shaped, and polished to eliminate flaws. When aproduct features more sophisticated optical design techniquesand glass, the results are better images. The quality of the opticalglass will make a difference in how bright, sharp, and colorful aview will be.Standard glass provides good image quality.Extra-low Dispersion Glass achieves the highest possibleimage resolution, contrast, and color fidelity—exactproperties vary among manufacturers. Some of the commonnames for this type of glass include: HD (High Density orHigh Definition), ED (Extra-low Dispersion) and XD (Extra-lowDispersion).CONSTRUCTIONYou may pay more for products using higher quality materials,more sophisticated designs and stricter tolerances, but this addsup to greater reliability in the field.Waterproof / Fogproof binoculars are sealed with o-rings toinhibit moisture, dust, and debris. The inside of the binocularis then purged of atmospheric air and filled with an inertgas that has no moisture content. This will prevent internalfogging from high humidity or altitude changes.ANTI-REFLECTIVE LENS COATINGSMetallic compounds, such as magnesium fluoride, arevaporized and applied to the optical glass in extremely thinlayers to reduce internal reflections, light scattering andglare. The result of adding more layers of an anti-reflectivelens coating to a greater number of glass surfaces is animprovement in image brightness, sharpness and contrast inlow light.Why anti-reflective coatings are needed.Anti-reflective coatings increase the amount of light thatpasses through the optical system so more light gets to youreye. The type and number of coatings applied to the lenses ina binocular or spotting scope make a significant difference inhow brilliant and crisp the views will be.Each time light strikes an uncoated glass surface about 4–5percent of the light is reflected. Without lens coatings, almost50 percent of the light could be lost as it passes throughthe multiple air-to-glass surfaces of a standard binocular orspotting scope.UNCOATED LENSESCOATED LENSES Nitrogen gas purging delivers fogproof, waterproofperformance. Argon gas purging guarantees superior fogproof andwaterproof performance. TIPKeep in mind that an investment in better optics maycost more. However, investing in higher quality optics not onlyyields better optical gain, but greater reliability when it counts. TIP The application of more coatings results in an increaseof light transmission, resolution, contrast, and color fidelity.Levels of anti-reflective coatingsFully multi-coated optics have all air-to-glass surfacescoated with multiple anti-reflective coating films, and offerthe highest image quality.Fully-coated optics have all air-to-glass surfaces coatedwith an anti-reflective coating film.Multi-coated optics have one or more surfaces coated withmultiple anti-reflective coating films.Coated optics have one or more surfaces coated with one ormore anti-reflective coating films.4Vortex OpticsVortex Optics at www.vortexoptics.comTHE BASICS OF OPTICSDETERMINING QUALITY5
Knowing what features matter to your use of optics is important.What follows is an explanation of basic features and specificationsto understand so you select optics that will perform to the levelyou need when out in the field.EYE RELIEFThe term eye relief refers to the distance between the ocular lensand where the image comes to focus and the entire field of viewcan be viewed. Proper eye relief is important for safe, comfortableviewing.Riflescopes: A minimum distance of three inches or moreprovides safe eye relief when viewing.FIELD OF VIEWAnother important number to understand is the field of view.When looking through an optic, you’ll see the field of view as thearea between the left and right edges of the image. The field ofview can be measured either in linear feet or in angular degrees.(One degree equals 52.5 feet).» Riflescopes: measured in feet @ 100 yards» Binoculars: measured in feet @ 1,000 yards» Spotting Scopes: measured in feet @ 1,000 yardsFIELD OF VIEWBinoculars and Spotting Scopes: Proper eye relief is importantto people who must wear eyeglasses or sunglasses whilelooking through optics. However, anyone planning to view forlong stretches of time will also benefit from optics with longereye relief.TWIST-STYLE EYECUPSFOLD-STYLE EYECUPSAdjustable eyecups allow for the best viewing if you weareyeglasses. Eyecups that twist up-and-down or fold backare common styles that are easily adjusted to accomodateeyeglasses or sunglasses.CLOSE FOCUSThis is the minimum distance to which you can focus an optic onyour subject. Close focus is more important for some applicationsthan others. For example, many binoculars will focus down to tenfeet or less—a feature that is especially important for watchingbutterflies, insects and birds.6Vortex OpticsA wide field of view has advantages when followingfast-moving action or scanning dense habitats. Whencomparing optics with the same size objective lenses,higher magnifi cations will generally have a narrowerfield of view.Vortex Optics at www.vortexoptics.comTHE BASICS OF OPTICSSPECIFICATIONS7
EXIT PUPILRESOLUTIONThis is the beam of light that exits each eyepiece and enters theuser’s eyes. You’ll want to have an exit pupil that is adequate forthe lighting situation in which you’ll be viewing. A person’s eyepupil can dilate from roughly 2 mm to 8 mm, depending on theperson’s age and the lighting situation:Resolution refers to the ability of an optic to distinguish details.A resolution chart contains groups of lines set in a series withprogressively smaller spacing—a design used to ascertain thelimiting number of lines per millimeter that optics can resolve.RESOLUTION CHART» In bright light the pupil will dilate to about 2–3 mm.» At dawn or dusk the pupil will dilate to about 4–5 mm.» In dark light the pupil will dilate to about 7–8 mm.A larger exit pupil will deliver brighter images—especially underlow light conditions.Look for the exit pupil by holding the optics a shortdistance from your face—seen as clear circles in thecenter of the eyepiece. TIP Use a resolution chart to determine how well a binocular,spotting scope, or riflescope can resolve fine details.WARRANTY TIPCalculate the exit pupil by dividing the objective lens bythe magnification.Example: 10x50 Binocular50 10 5.0 mmA manufacturer’s warranty ought to be considered a feature ofthe binocular—especially if you use the optics outdoors whereanything can happen. Most warranties offer a warranty limitedonly to initial defects with no protection from accidental damageor regular wear and tear. Progressive warranties cover optics inany situation, no matter what happens or who is at fault. TIPThe Vortex VIP warranty is an unconditional, unlimitedwarranty that offers the ultimate in customer service andprotection for your optics.8Vortex OpticsVortex Optics at www.vortexoptics.comTHE BASICS OF OPTICSEXIT PUPIL9
Yes, there are trade-offs and, no, there are no perfect optics. So,consider the following trade-offs when selecting optics.OBJECTIVE LENS SIZEObjective lens size is the main trade-off to consider. A largerobjective lens will deliver brighter images, especially under lowlight conditions, but it will be heavier and bulkier than a smallerlens. Think about how much you want to carry!OPTICAL GLASS QUALITYOptical glass changes in weight as the quality increases. Vortexoffsets the extra weight of the high-quality glass components byusing rugged, yet lightweight, housing materials.MAGNIFICATIONChoosing the higher magnification option has benefits, but it maynot always be the best choice for observation.Binoculars: As the magnification increases, you’ll see ashallower depth of field, a diminished field of view, and youmay experience a greater chance of image shake when viewing.Spotting Scopes: As the magnification increases, you’ll see areduction in image brightness.CLOSE FOCUS AND DEPTH OF FIELDIn general, optics with a close focus will generally have a shallowdepth of field.MORE OPTICS TERMSAlignment or Collimation – All elements (lenses or prisms)are in line along the optical axis. The misalignment ofelements results in diminished performance and can causeeye strain and fatigue.Astigmatism – Because the lenses in a binocular or spottingscope usually have a curved shape, the light rays passingthrough the lens will not all converge on the same focalplane. If this physical reality isn’t remedied in the overalloptical design, images will either be in focus in the centerarea or at the edge—but not in both areas at the same time.Astigmatism cannot be eliminated completely, but it canbe kept to a minimum. Avoid optics that exhibit too muchastigmatism.Chromatic Aberrations – Diminished resolution and colorfidelity display as green or purple fringing. This is the resultof a physical reality of color. Different colors move at slightlydifferent wavelengths and will have slightly different focallengths when passing through optical glass. The XD andED glass types reduce or eliminate this inherent problem ofchromatic aberrations.Contrast – This refers to differences in brightness betweenthe light and dark areas of an image. Because we see muchof the color spectrum, contrast also refers to differences inthe dimensions of hue, saturation, brightness, or lightness.Optics with superior contrast transmit colors that appearvery dense and well-saturated.Distortion – This is the inability of an optical system todeliver an image that is a true-to-scale reproduction of anobject. There are two types of distortion. In either case, thedistortion is due to a poor or compromised optical design.Any binocular or scope that exhibits distortion should beavoided.Barrel distortion – Image bows outward and looks bulged.Pincushion distortion – Image bends inward.Light Transmission – This is the percentage of light thatpasses through the binocular, spotting scope, or riflescopeto reach the user’s eyes. Light transmission will be higherthrough more expensive optics than through modestlypriced optics due to better optical designs, glass quality,and improved optical coatings.Resolution – Essentially the same as image sharpness,resolution is the ability of the binocular to separate anddistinguish thin lines with clarity.10 Vortex OpticsVortex Optics at www.vortexoptics.comTHE BASICS OF OPTICSTRADE-OFFS TO CONSIDER11
RIFLESCOPESTHE CONTROLS p.14 THE NUMBERS p. 21 RETICLES p.22Ready. Aim. Fire! Riflescopes and their features areas varied as the firearms they can sit atop. Thefirearm, as well as its intended application will dictatewhich riflescope will be the best fit. Understandingthe basics will make the right choice clear.12 Vortex OpticsVortex Optics at www.vortexoptics.com13
UNDERSTANDING THE CONTROLSWindage, oculars and parallax—oh my! Riflescopes generally haveseveral adjustable features. When broken down to the basics,many are commonly shared and relatively simple. Once basicfeature terminology and their functions are understood, you’ll beable to select the right riflescope with pinpoint accuracy.Reticle FocusMagnifi cationAdjustment RingElevationAdjustment KnobOCULAR FOCUSUse the ocular focus to tune the reticle image for maximumsharpness. This adjustment will be slightly different for everyshooter, and only needs to be set one time. To adjust, begin bybacking the focus out until the reticle is clearly fuzzy. Whiletaking short, quick looks through the scope, turn the focus inuntil reticle image is sharp and crisp to the eye immediatelyupon viewing. Do NOT use this focus to adjust the target image.ADJUST THE RETICLE FOCUSSide Focus(Select Models)Ocular LensWindageAdjustment KnobTUBE DIAMETERRiflescope main tubes come in several diameters, including1 inch, 30 mm, 34 mm and 35 mm. Larger diameter tubescan provide increased travel ranges for windage and elevationadjustments as well as greater strengths. Being aware of tubediameter is also very important when selecting rings to mount thescope.MAGNIFICATION ADJUSTMENTUse the magnification adjustment to change the “power” levelof the riflescope— adjusting from low to high magnificationdepending on the shooter’s preference.Lower magnifications will provide brighter images and widerfields of view which can be helpful in low light and/or closerange shooting and with moving targets.Higher magnifications will have narrower fields of view anddimmer images, but will offer better ability to shoot smallertargets at longer ranges.ADJUST THE MAGNIFICATION1-Inch Tube30 mm Tube TipA common misconception about greater tube diameteris that it always provides a brighter image; this is usually not thecase.14 Vortex OpticsVortex Optics at www.vortexoptics.comRIFLESCOPESObjective Lens15
ELEVATION AND WINDAGE TURRETSTurrets are used to adjust the bullet’s point of impact downrange, and will be marked in either MOA or MRAD scales.Turrets come in several styles, depending on user preferences.Exposed target-style turrets are used by long rangeshooters who routinely “dial” elevation corrections forbullet drop at long range.ElevationKnobArc MeasurementsMRAD (Milliradian) arc measurements are based on theconcept of the radian. A radian is the angle subtended at thecenter of a circle by an arc that is equal in length to the radiusof the circle. There are 6.283 radians in all circles. Sincethere are 1,000 milliradians in a radian, there are 6,283milliradians (MRADs) in a circle. An MRAD will always subtend3.6 inches for each 100 yards distance.Most riflescopes using MRAD turrets will use 1/10 mradmechanical clicks which subtend .36 inches for each 100yards of distance.Bullet DropWindage Knob1 Radian1,000 Milliradians(MRADs)Capped style turrets are often used by shorter rangeshooters and hunters, who may prefer the security andlower profile of this type.Windage KnobMOA (Minute of Angle) arc measurements are based on theconcept of degrees and minutes in a circle. There are 360degrees in a circle, 60 minutes in a degree for a total of21,600 minutes in a circle. An MOA will always subtend 1.05inches for each 100 yards distance. Most riflescopes usingMOA turrets will use ¼ minute mechanical “clicks” on theturret which subtend .26 inches for each 100 yards distance.Bullet Drop57.3 Degrees3,438 Minutes-of-Angle(MOAs)16 Vortex OpticsVortex Optics at www.vortexoptics.comRIFLESCOPESElevationKnob17
IMAGE SHARPNESSWhat is parallax?Some riflescope models feature an adjustment that allows you totune the target image for maximum sharpness. This adjustmentmay be on the objective lens or near the turrets on the side of theriflescope.Parallax is a phenomenon that results when the target image doesnot quite fall on the same optical plane as the reticle within thescope. This can cause an apparent movement of the reticle inrelation to the target if the shooter’s eye is off-centered.Adjustable Objective Lens Focus – This adjustment dial ismarked with approximate yardages to aid in initial setting,and should be matched to the targets distance. Final focussetting should be checked by moving shooters head back andforth slightly, watching for any shift of the reticle on the target(parallax). If shift is observed, the dial should be adjustedslightly until shift is removed. Once this focus is correctly set,shooting errors due to parallax will be eliminated.» When the target image is not focused on the reticle planeand your eye is off-center behind the scope, parallax occurs.This is because the line of sight from the eye to the focusedtarget image does not coincide with the reticle aiming point.Reticle Aiming PointFocused ImageAdjustable ObjectiveLens FocusReticle PlaneEye is not centeredbehind the scope.» When the target image is not focused on the reticle planeand your eye is centered directly behind the scope, no parallaxoccurs. This is because the line of sight from the eye to thefocused target image coincides with the reticle aiming point.Reticle Aiming PointSide Focus Adjustment – This adjustment serves the exactsame purpose as an adjustable objective, but is moreconveniently located on the left side of the riflescope. Theadjustment dial is marked with approximate yardages to aid ininitial setting, and should be matched to the targets distance.Final focus setting should be checked by moving shootershead back and forth slightly, watching for any shift of thereticle on the target (parallax). If shift is observed, the dialshould be adjusted slightly until shift is removed. Once thisfocus is correctly set, shooting errors due to parallax will beeliminated.Reticle PlaneEye is centered directlybehind the scope. Tip Correctly focus the target image so it falls on the sameoptical plane as the reticle within the riflescope.» When the target image is focused on the reticle plane,parallax cannot occur—even if your eye is not centeredbehind the scope. This is because the line of sight from theeye to the focused target image always coincides with thereticle aiming point no matter where you position your eye.Focused ImageReticle Aiming PointAdjustable Side FocusReticle Plane18 Vortex OpticsVortex Optics at www.vortexoptics.comEye can be centered anywherebehind the scope.RIFLESCOPESFocused Image19
RETICLE ILLUMINATION ADJUSTMENTUse the reticle illumination adjustment to “light up” all or a portionof the reticle within a riflescope—allowing the reticle to be moreeasily seen against a dark background. The intensity level canusually be adjusted and is commonly placed on the ocular or leftside of the scope, though it can be located in other positions.Illumination is normally powered by a small watch type battery.UNDERSTANDING THE NUMBERSTHE RIFLESCOPE CONFIGURATIONMagnification is indicated by the first set of numbers inthe example of a 4–16x50 riflescope—the magnificationranges from 4x up to 16x. Some riflescopes do not have azoom eyepiece and use a single number to indicate a fixedmagnification, as in a 2x20 scope.Illumination AdjustmentKnobMagnifi cationScaleUse the zero stop adjustment to prevent the elevation turret frombeing rotated downward past the point of original zero. It is mostuseful for shooters who routinely adjust the elevation turret “up”for long range shots, allowing them to always easily and accuratelyreturn “down” to their original zero setting. Zero stops are usuallyseen on higher quality long range or tactical riflescopes.Objective LensAdjusting the zero point.EYE RELIEFWith proper eye relief, there will be a space cushion thatprotects the eye from recoil of the firearm. Keep in mind thateye relief typically decreases as magnification increases.20 Vortex OpticsVortex Optics at www.vortexoptics.comRIFLESCOPESZERO STOP ADJUSTMENTObjective Lens Size is indicated by the last number in the4–16x50 example—referring to the diameter of the objectivelens in millimeters. If all other things are equal, largerobjectives can yield brighter images at high magnifications.This is an advantage for hunting at dusk and dawn whenanimals are most active.21
UNDERSTANDING RETICLESFrom the simple Plex crosshair to first focal plane hashmarkbased, mrad reticles with wind dot references—every reticleshines under certain conditions and when paired with anappropriate firearm.FIRST AND SECOND FOCAL PLANE RETICLESAll reticles will be termed either first (FFP) or second (SFP) focalplane, depending on their internal location within the riflescope.FFP – This style of reticle will grow and shrink as magnificationis changed. The main advantage to this style reticle is that thereticle subtensions used for ranging, bullet drop compensationand wind drift corrections are always accurate at anymagnification.HOW TO RANGE WITH MRAD AND MOA RETICLESUsing simple formulas, both MOA and mrad hashmarked reticles canbe used to estimate distance. This is a useful skill—and provides agood back-up should your laser rangefinder fail or lose battery power.To range with a reticle formula, you can use either the vertical orhorizontal scale. Place the reticle on a target of known width orheight and read the number of mrads or MOAs spanned. You willobtain maximum accuracy in ranging by calculating as exact ameasurement as possible—down to fractions of an mrad or MOA.Accurate measuring will depend on a very steady hold. The rifleshould be solidly braced using a rest, bipod or sling when measuringthe size of the target or nearby object. Once you have an accuratereading, use a formula to calculate the distance.Mrad Ranging FormulasKnown Width or Height of Target (Yards) x 1000Target Width or Height (Measured on Reticle in MRADS)Known Width or Height of Target (Meters) x 1000Target Width or Height (Measured on Reticle in MRADS)Known Width or Height of Target (Inches) x 27.8High Magnifi cationSFP – This style of reticle does not change size whenmagnification is changed. The advantage to this style of reticleis that it always maintains the same ideal visual appearanceand will not appear “too fine” at low magnification or “tooheavy” at high magnifications.Target Width or Height (Measured on Reticle in MRADS) Range (Meters) Range (Yards)MRAD EXAMPLE – Ranging a 6-foottarget stand (2 yards) at 4 mrads toget 500 yards.2 x 10004 mrads 500 YardsMOA Ranging FormulaKnown Width or Height of Target (Inches) x 95.5Target Width or Height (Measured on Reticle in MOAs)Low Magnifi cationHigh Magnifi cation Range (Yards)MOA EXAMPLE – Ranging a 6-foottarget stand (72 inches) at 10 MOAto get 688 yards.72 x 95.510 MOA 688 Yards TIP You can substitute 100 for 95.5 for faster calculating,but this will produce a five percent over-estimation error of theyardage distance.22 Vortex OpticsVortex Optics at www.vortexoptics.comRIFLESCOPESLow Magnifi cation Range (Yards)23
BINOCULARSDESIGN p.26 THE NUMBERS p. 28 BASIC ADJUSTMENTS p.29What binocular should I get? The answer to thisquestion is generally found by asking another.What do you plan on using it for? A person scouringa vast western landscape will have different needsfrom another who finds themself immersed in astand of Midwest hardwoods. Read ahead about thevarious features of different binoculars and you’ll SEEwhat we’re talking about.24 Vortex OpticsVortex Optics at www.vortexoptics.com25
BINOCULAR DESIGNThere are three main binocular designs: the roof prism, Porroprism, and reverse Porro prism. These designs come in a variety ofweights and sizes. The greatest factor in determining the weight ofa binocular is the size of the objective lens: the larger the lens, theheavier the binocular.Compact binoculars generally have objective lenses of 28 mmor less and can weigh from a few ounces to under a pound.PORRO PRISMMany people will recognize the traditional binocular shape of aPorro prism by its offset barrels. Named after the Italian opticaldesigner, Ignazio Porro, Porro prism binoculars have objectivelenses that are spaced wider apart than the eyepieces. This designoffers a rich depth of field, wide field of view, a three-dimensionalimage, and delivers good quality at a reasonable cost.Mid-size binoculars include models with objective lensesbetween 30 mm and 35 mm.Full-size binoculars generally have objective lenses over 35mm and can weigh from twenty ounces to around two pounds.Center FocusOcular sTwist-up EyecupMid-SizeModelCompactModelsROOF PRISMObjective LensREVERSE PORRO PRISMThe reverse Porro prism is a compact version of the full-size Porroprism binocular with the eyepieces spaced wider apart than theobjective lenses.Center FocusOcular LensCenter FocusTwist-up EyecupStrapAttachmentOcular LensDiopterAdjustmentTwist-up EyecupStrapAttachmentDiopterAdjustmentObjective LensObjective LensBINOCULARSNamed for the roof-like appearance of the prisms, the roof prismbinocular has objective lenses and eyepieces positioned in astraight line and is appreciated for a streamlined, durable chassis.Phase correction coatings on the prism glass keeps the light incorrect color phases—enhancing the resolution, contrast and colorfidelity. Fine quality in this complex prism design is possible as aresult of care in engineering and design.Tripod Adapter Socket26 Vortex OpticsVortex Optics at www.vortexoptics.com27
THE NUMBERSBASIC ADJUSTMENTSIDENTIFYING THE CONFIGURATIONADJUST THE INTERPUPILLARY DISTANCEWhen you look at your binocular, you’ll notice numbers like 10x50(read as “ten by fifty”) printed on the binocular.The interpupillary distance (IPD) is a measurement of the distancebetween the centers of a person’s left and right eye pupils. Abinocular also has an IPD measurement that can be adjusted.10 x 50 ModelThe hinged design of a binocular allows you to match the IPD ofyour eyes to that of the binocular so that you see a single imagethat is free of shading. If the IPD is not correctly adjusted, youmay see shading over part of the image. With correctly adjustedbinoculars, you will see a single image without the shading.The first number (10x) refers to the magnification provided bythe binocular (or how many times larger an object will appearthan when viewed without magnification). Binoculars vary inmagnification, but 8x and 10x are most common. TIPThe second number (50) refers to the diameter of the objectivelens in millimeters. Objective lenses vary in size from 15 mm to50 mm and beyond. The size of the objective lens determineshow much light the binoculars can receive and how bright theresulting images will be. The size of the objective lens alsoaffects the size of a binocular.IPDTo adjust the IPD of your binocular, simply rotate the binocularbarrels inward or outward to line up the ocular lenses with youreyes.Adjust the IPD of your binocularfor the best viewing possible.Exit pupil is especially important for viewing in low lightconditions. If your primary time for viewing is during thebright light of day, then a binocular with a smaller objectivelens of 26 mm or less will do just fine. If you want thebrightest possible image during near-dark conditions, you’llwant to choose a binocular with an objective lens in the 33mm to 56 mm range.IPDWide field of view has advantages when following fast-movingaction and scanning dense habitats. The field of view ismeasured in feet at 1,000 yards or degrees:Example: 388 feet @ 1000 yards6.0 degreesClose-focus binocular will focus down to ten feet or less. Thisfeature is especially important for watching birds, insects andbutterflies.28 Vortex OpticsThe IPD corresponds tothe spacing between aperson’s eyes.Vortex Optics at www.vortexoptics.comBINOCULARSAs magnification increases, it may be more difficult tohold the binocular steady so the image may appear to shake. Inaddition, an increase in magnification generally causes a decreasein image brightness. 7x or 8x magnification is considered adequatefor woodland settings, while 10x is preferred for viewing at greaterdistances.29
ADJUST THE EYECUPSPROPERLY FOCUS THE BINOCULARAdjusting the eyecups up or down allows the user to see a full fieldof view. This is important for people who must use eyeglasses orsunglasses. The two main styles of eyecup design are:For the best views, follow this two-step process to properlyadjust the center focus and diopter. Choose an object that isabout 20 yards away from you and stay in the same spot untilyou have adjusted the binocular for your eyes.Retractable eyecups that twist up and down. Multi-positioneyecups let you choose the most comfortable position.Flexible eyecups that fold back for maximum eye relief witheyeglasses.TWIST EYECUPS1. Adjust the center focus – Start by closing your right eye orcovering the right objective lens with your hand. Focus yourleft eye on the object and adjust the center focus wheel untilthe image is in focus. Leave the center focus in this positionas you adjust the diopter.Adjust the center focus.FOLD BACK EYECUPSWith Glasses – If you wear eyeglasses or sunglasses, rest theeyecups of the binocular against your glasses with the eyecupsfolded back or twisted down. If the eyecups stay fully extendedwhen wearing eyeglasses, images will appear as if you arelooking at them through a tunnel.2. Adjust the diopter – Start by closing your left eye orcovering the left objective lens with your hand. Look throughyour right eye and adjust the diopter ring (generally foundon the right eyepiece) until the object is in focus. Make noteof this diopter setting in case you need to set it again. Fromthis point on, you will only need to use the center focuswheel.Retract the eyecups when viewingAdjust the diopter setting.Without Glasses – If you do not wear eyeglasses or sunglasses,extend the eyecups to provide the proper distance for seeingthe full field of view. If the eyecups do not stay fully extended,you may see black crescents in the field of view. TIPLocking Diopters – Some models feature a diopter thatlocks the settings. If the diopter locks, lift the diopter ring(or follow manufacturer instructions) to unlock. Then, lookingthrough your right eye, adjust the diopter so that the object is infocus. Make note of this diopter setting in case you need to setit again. Push the diopter ring down to lock—from this point on,you will only need to use the center focus wheel.Extend the eyecups when viewingwithout eyeglasses or sunglasses.30 Vortex Op
2 Vortex Optics Vortex Optics at www.vortexoptics.com 3 For hundreds of years, people have used optics to enhance vision, as well as optimize effectiveness of shooting equipment. Whether glassing up that big buck, taking aim, or simply observing the natural world, great optics make great experiences. Optics can be very task-specifi c.
NXS 2.5-10 x 42 Compact 16 NXS 3.5-15 x 50 17 NXS 5.5-22 x 50/56 18 NXS 8-32 x 56 19 The SHV family of ri escopes 20 SHV 3-10 x 42 21 SHV 4-14 x 56 22 SHV 4-14 x 50 F1 23 SHV 5-20 x 56 24 The Competition family of ri escopes 25 Competition SR Fixed 4.5 x
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