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Hide & Seek: How to Spot Trout in the Light and Shadows

Spotting trout is a combination of skill, strategy, and having the right polarized lenses and fishing frames to reduce glare and improve contrast.

Hide & Seek: How to Spot Trout in the Light and Shadows

A guide and angler are perched up on a boulder in Slovenia so they can look down into the river and spot their quarry. (Barry Beck photo)

I have a fishing buddy named Greg. He's not just any fishing buddy—we sort of grew up fly fishing together, and the things I didn't learn from him, I learned with him.

Decades ago, we both lived in Colorado and we frequently fished the Fryingpan River below Ruedi Reservoir. The first mile below the dam was loaded with big trout, and Greg caught a lot of them. I caught a few.

Greg and I grew up in the same hometown, and we had almost identical fishing experience and skills, with one exception. Greg was naturally good at spotting trout, and I wasn't. He walked the river slowly or stood stock still. To the uninitiated, he looked as though he was staring at the river, but he wasn't. He was scanning through the surface and studying shapes, colors, and movements along the bottom.

While Greg was a sniper, I relied on sheer firepower. I could wade across any river and pepper every inch of water with a thousand casts. That favored my skill set. With so many fish in the river, I reasoned that as long as my fly was out there, I was in the game. My outlook was like Jim Carrey's character in the film Dumb and Dumber saying, “So you're telling me there's a chance?”

The fish I did catch were often under Greg's tutelage. He'd spot a fish for me, and describe its exact location.

“See the rock with the branch stuck on it? Look 10 feet downstream and you'll see a small triangle-shaped stone on the bottom. The trout is right below that triangle.”

With a lot of rod pointing and searching, I'd eventually find the trout, or else Greg would just direct my casts to the right spot, and like a color commentator, announce exactly what the trout was doing.

“He moved away from your flies that time, so you better change” or “he just had a look but refused at the last moment.” Knowing how a fish reacts to your flies gives you a distinct advantage. It's like knowing your opponent's poker hand.

When the fish did eat the fly, Greg let me know well before the indicator moved. Working as a team—and with the benefit of his fish-spotting abilities—we caught many 5- to 10-pound trout and larger on size 20 and 22 flies.

My “shotgun approach” combined with efficient casting did catch trout at other times and places. When you are floating a high and muddy river in a drift boat, and pounding the banks with big streamers, your fish-spotting skills don't add up to one iota of a difference. You are searching with your flies.

When the water is clear, however, it's often more productive to search with your eyes. This is especially true on small and medium streams where there is a lot of fishing pressure, and also on tailwaters where the trout are feeding mostly on small food items. When the fish are feeding on tiny stuff, or when there are a lot of fishermen around, the trout aren't likely to charge across the river to take your fly. These fish are conditioned to be skeptical. You have to bring the fly right to them—not within inches, but right down the pipe so all they have to do is open their mouths. On these highly pressured fisheries, sight-fishing skill can make the difference between a successful day, or . . . “it was just nice getting out there.”

Sight fishing is also important on clear wilderness rivers where the fish don't see many people. On these rivers, the silhouette of a fisherman, the splash of a fly line, or any movement that's out of the ordinary can just shut down the fishing. On a pressured river, the trout must continue feeding despite a parade of fishermen—otherwise they will starve.


But on a backcountry stream in New Zealand, a bad cast can shut down a pool for hours, or even the rest of the day. You must find the fish first, and make the first cast the best cast. With each successive attempt your chances of catching the trout drop dramatically because each time you risk spooking the fish.

When Greg and I fished the Fryingpan years ago, we were young, and Greg had 20/10 vision. This means he could read an eye chart at 20 feet as well as normal people could read it at 10 feet. This helped him stand back from the trout and spot them without spooking them.

This was a genetic gift he was born with, but spotting trout isn't as straightforward as merely reading tiny letters on an eye chart. It's a skill you can study, practice, and improve. And as with every skill, knowledge is power. Before you begin practicing your skills on the water, it's important to have the right gear, know what to look for, and have the right strategies in mind to make it all work.

They See You

When you start visually stalking trout, you should realize that for you it's a game. You fish for sport, but for the trout, detecting predators is a matter of life and death. The trout that are particularly good at it survive and grow large.

My point is that when you are looking for them, they are also looking for you. If they spot you, they may bolt for cover or just stubbornly stop feeding. Because of this two-way street, it's often true that the easiest trout to spot are the hardest to catch. Conversely, trout that are difficult to spot are generally easier to catch.

Fish that are easy to see are often in slow, flat water, which makes a stealthy, natural presentation difficult. This is the wheelhouse of selective trout, where they are sensitive to micro-drag and can study your fly carefully.

One of my favorite tailwater streams in the Rockies has a slow, glassy bend pool below a bridge. The big trout in this flat pool are easy to see, and they attract many fishermen. It's hard to walk past this aquarium, and many people spend their entire day fishing there, with very little success.

I've learned to simply walk past these obvious fish, down to an area with a steeper gradient and many erratic boulders. The broken pocketwater there offers plenty of places for trout. The rocks provide shelter from the current, and the turbulent water gives the fish a sense of security because they are more difficult to spot in these places. But I've found that these difficult-to-see fish are very catchable if you study the water carefully. Predict where you think there might be a fish, and then use the trout's blind spots to get as close as you can. If possible, position yourself to take advantage of the angle of the sun. Use moving windows of flat water to catch glimpses of the river bottom and look for unusual shapes, movements, colors, and shadows. You won't often see the whole trout, but you'll often get clues that help you piece an image together. Fish that are sitting still are likely not feeding, but the feeding fish will move and give themselves away.

Because they are in water where they are difficult to spot, you are more likely to be able to approach and cast without spooking the fish. The trout in fast pocketwater have less time to inspect your fly, and the speed of the water forces them to make quick, ill-advised decisions.

Most important, just by being in faster water, these fish have qualified themselves as feeding fish. You may see fish in the clear glassy water having a snack here and there, but a lot of times, when trout sit in slow pools where they are easy to see, they are generally more interested resting than feeding. When they want to chill out, they choose a place where they don't have to fight the current and they can plainly see threats from afar. So ignore these obvious fish and hone your sight-fishing skills to spot trout in trickier water.

Focus Zones

As the above example demonstrates, it's helpful to know where to look before you start looking. You simply can't just look anywhere and everywhere, trout are not spread out evenly like butter on bread. There is a lot of dead water out there with no fish. Every good angler knows that trout prefer to feed in specific locations, and fly fishers who are already good at identifying these spots have a step up when it comes to sight fishing—they know where to start looking.

Fly fishing, high stick nymphing, pocket water, blane chocklett, boulders
Trout that are easy to spot in slow, flat water are often on high alert and difficult or impossible to catch. Focus your sight-fishing efforts on broken, turbulent water where trout are more likely to be feeding confidently, and have less time to inspect your flies. (Jay Nichols photo)

When you are looking for feeding trout, you should almost always be focusing on places where there is a definitive change in current speeds—places where slower water meets faster water. Trout always use the current to their advantage and prefer to rest in slower water while a faster current brings food to them. If they sit in slow water they won't have much food come to them. If they are in the fast water, they exert too much energy. The perfect spot is where these two current types meet, so look for anything that creates disturbances in the river flow—rocks, logs, tree roots, sod clumps, fence posts, and a hundred other types of protrusions along the bank will create current lines and seams where trout feed. Corners, islands, incoming side channels, and every twist and turn in the river will also create changes in current speed.

These are all linear obstructions and breaks—types of feeding lanes you could easily indicate on a flat map. However, rivers are three-dimensional environments. Changes in current don't always happen on a plane with a left and right side. There are also vertical current seams where the water is slow near the bottom and fast on top. Gravel bars, drop-offs, eroded holes, and submerged rocks and logs can all create these types of feeding zones for trout.

Don't just walk aimlessly along a river looking for trout. You won't find much success. Zero in on the places where you know fish are likely to feed, and you'll have much more success with your sight fishing. And here's the most important product of this type of scrutiny—once you see a fish in a spot, you have confirmed that this is a good feeding location even before you cast a line. Put this in your data vault. You'll know to look in that spot the next time you're around, and you'll build a repertoire of places where you know there are likely to be trout.

Trout Camouflage

Trout always face into the current, so the most obvious things to look for are shapes that are oriented upriver. Our eyes immediately discount everything that doesn't obey this law of river hydraulics. But that still leaves a lot of rocks and wood along the river that are fish-shaped and fish-sized, and aligned in the right direction.

Over the decades, I have found that for my brain, looking for fish shapes doesn't often work. Trout camouflage in most cases is just too good, and you won't often see a whole trout shape unless it's silhouetted against a patch of light-colored sand or some other contrasting background. In most cases, their camouflage is perfectly suited to the stream bottom, and it works to break up their outlines.

If your brain is focused on looking for fish-shaped objects, you will likely spend much of your day casting at rockfish and stickfish. Instead, your primary focus should be on movement. A camouflaged turkey hunter sitting motionless against a tree trunk can be nearly invisible, but when he moves, the turkey will see him. Rocks and sticks don't move, but trout always move, and the trout that move a lot are the ones you're likely to catch.

Trout don't just to move to feed, they also chase other trout from their turf—they are territorial and that often gives them away. When they chase interlopers, they often return to their primary feeding position. I love these bully trout, because they are often aggressive when a fly comes along.

A trout feeding subsurface will often exhibit quick lateral movement when it grabs a nymph or larva drifting near the bottom. These sudden, erratic movements often result in flashes in the sunlight as they turn. The slow pulsating movement of a nonfeeding trout is harder to discern with the movement of the water, and the weeds, and changing light.

Speaking of light . . . sunny days help your eyes penetrate the water more easily, which is why sight fishing is easiest from about 10 A.M. to 2 P.M. The light helps you see into the water better, but it also casts shadows. And while trout do have excellent camouflage that optically hides their outlines, they still create solid shadows. I can't count the times I've been able to locate a telltale trout shadow on the bottom, and then after careful observation, actually discern the fish. There are lots of shadows and dark spots along a river bottom, so you don't want to get sidetracked looking at the wrong things. The key is to look for shadows that are in the right places, and shadows that are moving like trout should.

Fly fishing, sunglasses, polarized
Polarizing filters in quality sunglasses are sandwiched between polycarbonate or glass lenses. Green, blue, or silver mirrors can also be layered inside the lenses for durability. (Photo courtesy of Magpul)

After you find the shadows of a trout, you'll be able to find the trout itself. I learned this trick long ago while saltwater fishing—bonefish have scales like mirrors, and the fish themselves can be difficult to see, but they cast very obvious shadows. When a fly fisher sees five bonefish at 125 feet, what they most often see first is five shadows moving across the sand. When they get to about 60 feet, you can actually see the fish.

Color can also sometimes play a role in helping you locate trout. Trout camouflage is excellent, but sometimes their diet, the season, and the turbidity or clarity of the water can all affect their color. Trout that eat a lot of scuds, shrimp, and midges are often brightly colored because of chitin, a long-chain polymer that is the major component of the exoskeletons of arthropods.

Trout also change colors in reaction to their environments. In turbid water they are often very silvery. When the water is clear and they are exposed to a summer of sunlight, their freckled patterns become more pronounced to blend into the bottom of the river.

Their color changes are also more pronounced near spawning seasons when their colors are at a seasonal peak. Some of my best brook trout have come from spotting the white outlines their fins against the dark bottoms of Appalachian mountain streams. I couldn't really see the trout, but those lateral white lines were a dead giveaway.

When they have bright red stripes, rainbows can give off a red glow in the water that is apparent when viewed from the side. Sometimes you can't see a fish at all, just a hint of red color that seems out of place. I have also been fooled by brown trout in this way. Some browns get very pronounced red spots on the adipose fin and toward the rear, and that red color gets me thinking there's a rainbow in that spot. Either way, I'm happy!

Sight-Fishing Strategies

Sight fishing is both a natural skill and a mental strategy. My buddy Greg moved very slowly while sight fishing the Fryingpan River. Our river mileage was short, and there were so many fish that you could potentially spot a new target with each step. Moving slowly made sense.

In New Zealand I've hiked for many miles in a day with the late, great Simon Dickie, and I could barely keep up with him. He only stopped to look for trout long enough for me to catch up with him, and then we'd move on. When you're very good at sight fishing and the trout are spread out, it makes sense to move quickly.

Your eyes are your primary tools when scouting for trout, but you have two types of vision: foveal vision and indirect or peripheral vision. Foveal vision gives you 100% acuity on the things your eyes are specifically focused on, and your peripheral vision is everything else. When you are searching a river, “everything else” becomes very important because your eyes can only focus on one thing at a time, and your peripheral vision is much better at detecting movement. This is how prey species notice they are under attack—they use their peripheral vision to detect movement.

So don't get caught just staring at a single spot on the river bottom. This can be fatiguing and overrule your peripheral vision. Scan with your eyes. Let your gaze wander, and try to look at everything and nothing in particular. See the whole picture, not just a single spot on it, and you'll begin to notice more trout.

In a perfect spotting situation, you would have blue skies, bright sun directly overhead, and no wind to disturb the surface of the water. If it happens, count yourself lucky. These are all factors you can't really control. What you can control in terms of lighting is where you fish and how you scout.

Defeating Glare

To spot trout, it's helpful to have a dark background to look against. If there is a tall stand of trees on the other side of the stream, or a tall cliff, it reduces the amount of glare coming into your eyes. Dark clouds on the horizon and bright sun overhead can produce the same effect.

Glare is always your enemy. This is why you see people cupping their hands around the sides of their sunglasses—to reduce the extra glare coming in from the sides. If you have a good pair of fishing frames that fit you well, you shouldn't have to cup your hands around your sunglasses. Good frames fit snugly against your cheekbones and eyebrows, and have wide arms at the temples to block side glare. Fashion frames aren't built like this. If you are going for the Tom Cruise in Risky Business look, you'll be taking more selfies than fish pictures. You want full-coverage frames that wrap around your face and replace those cupped hands.

fly fishing, ladder, sight fishing, Uncompahgre River
Colorado guide Matt McCannel uses a stepladder to spot trout on the Uncompaghre River. His style is to hunt the biggest trout in the river, so his clients don't cast until McCannel can see the trout and evaluate their reactions to the presentations. (Nick Swingle photo)

High-performance fishing glasses come in specific sizes to fit the size and shape of your head and face, so it's important to try on a lot of frames to get the ones that fit you best. Frames that are too loose allow glare to creep in, and may slip off your face. Frames that are too tight are uncomfortable. You'll notice that companies specializing in performance fishing frames have dozens of frame styles, and each is sized differently. Find one that fits you and stick with it.

Performance frames are also shaped to reduce the amount of glare coming in from the top and sides. Costa Blackfin and Fantail Pro frames, for instance, have large side shields and hooding over the eyes to reduce the amount of light coming in around the frames.

Another glare-reduction strategy is to gain elevation. Climb a tree, get up on a boulder, or walk along a high riverbank so you can look down into the water. This way, the background is the river bottom, and you're not getting all the bounced light from the horizon.

Have you ever fished an evening hatch and crouched down low so you can see your tiny dry fly floating on the surface? In this instance, you are enhancing the glare on the water to silhouette your fly against the gunmetal surface of the water. Getting up high in a cliff or cutbank does the exact opposite. It helps eliminate reflected or indirect light, allowing you to see directly into the water much better.

These elevated positions are great for spotting trout, but are usually impossible fishing locations, so to use them, you need to use the buddy system. Guides do this for you all the time, but you don't need to be on a guided trip to use a little teamwork. You'll find it's just as fun to be the fish spotter—the achievement of catching a difficult trout is equally yours, and you learn a lot from being the “eyes” of the operation. You get to observe trout behavior, see how the fish react to the flies and the fly line, and you'll see the strike before your buddy even realizes it. It's no wonder guides enjoy their jobs so much!

Gaining an elevated position is so critical to sight fishing that Colorado guide Matt McCannel carries a stepladder with him each day on the Uncompaghre River. The guests don't cast until McCannel is up on that ladder and can see a target. Most fishermen don't even know there are giant trout in that little creek, let alone catch them, but McCannel regularly catches 10-pound and 15-pound trout and larger using his sight-fishing techniques, tiny flies, and 6X fluorocarbon tippet. It's a case study in the difference between hunting trout with your eyes, and the chuck-and-chance-it strategy of many other fishermen.

On cloudy days, fish spotting is difficult, but not only because it's darker. When light comes through clouds, it is bouncing in every direction. The result is water with an opaque sheen. But there's an upside to these cloudy days. The trout realize they are difficult to spot, they feel comfortable and safe from predators, they move into shallower feeding areas, and they feed more actively.

We've all experienced lousy fishing on bright sunny days, and good fishing on overcast days. Fish can actually see better on overcast days because they don't have bright sun shining in their eyes, and they have better contrast in their field of view. This helps them to see their food better, and also to see you.

Days like this can be a huge opportunity, and this is when good sunglasses are especially critical. Almost any pair of polarized glasses will benefit you when it's sunny, but for cloudy days, regular sunglasses become a liability due to visible light transmission (VLT) rates. Sunglass lenses designed for bright sunny days often have a VLT of 10 percent. That means they block 90 percent of the incoming light. These are often gray lenses with blue or silver mirrors. They block a lot of light and keep you from squinting, and they help you see fish when the sun is bright, but when it's cloudy, you may as well be wearing a blindfold. You shouldn't be wearing sunglasses with a VLT of 10 for trout fishing. They are for offshore saltwater fishing or for spring skiing.

Lenses with a VLT of 12 to 18 percent are often recommended as good “all-around” trout-fishing lenses. These types include Costa's copper and copper silver mirror lenses (12 percent VLT), Smith's ChrompaPop bronze mirror (14 percent), and Bajio's rose mirror/red base lenses (18 percent).

However, on overcast days, and in early mornings and evenings when trout are most likely to be feeding confidently, this still isn't enough light getting through. Costa's Sunrise Silver Mirror lenses (25% VLT) and Smith's Low Light Ignitor lenses (40% VLT) are objectively the best lenses in this category. Both are yellow, a lens color that is a detriment to color vision, but greatly enhances contrast when viewing objects against a dark background.

This isn't just subjective fishing advice, this is proven by scientific studies published by the National Library of Medicine. [See “Contrast is enhanced by yellow lenses because of selective reduction of short-wavelength light” by S Wolffsohn 1, A L Cochrane, H Khoo, Y Yoshimitsu, S Wu. The Editor.]

fly fishing, costa sunglasses, fishing frames, side glare
High-performance fishing frames should fit snugly on your face, and they should have adequate shielding to prevent side glare. A hat and a hoody can also greatly reduce this type of glare and enhance contrast in the foreground. (Photo courtesy of Costa)

As I mentioned earlier, color can be helpful in spotting trout in sunny conditions, but without adequate light, you'll rarely notice the red of a rainbow stripe or the pumpkin color of a brown trout, as these colors are all reflected light. In low-light conditions your best ally is contrast, so you can see shapes and outlines and detect movement.

I use Costa Silver Sunrise lenses in low-light situations because if the sun breaks out momentarily, or for half the day, I can still wear them effectively.

Smith's Ignitor lenses allow even more light though, so you'll need to carry an alternate pair of glasses for changing light conditions.

To break away from the topic of spotting fish for just a moment, there are other important reasons to use low-light lenses. In my 40 years of fly-fishing experience, I've noticed that a lot of the wading slips, falls, and mishaps I've seen often happen in the mornings and evenings when it's too dark for average sunglasses, and fly fishers tend to remove their polarized glasses. They lose their ability to see the bottom, and they slip and fall, or twist a knee or ankle. Low-light lenses will not only help keep your footing at the end of the day, they help you see the contours and structures along the bottom even in difficult lighting situations, so they make you a better fly fisher whether you're sight fishing or not.

Another common problem I see is when fly fishers take off their dark sunglasses in the late afternoon and evening, and leave their eyes completely unprotected. This is a safety concern. Your sunglasses aren't just to help you spot fish. They protect your eyes from hooks, and low-light lenses can mitigate this problem.

At La Villa de Maria Behety Lodge on Argentina's Rio Grande, the best fishing is at sunrise and at dusk. You take a six-hour break at midday and fish until well past dark. To protect the guests' eyes, the guides hand out clear safety glasses in the evening, but I've found low-light lenses to be better in these situations because the optics are better than plastic safety glasses, and the polarization helps me see my footing more clearly.

How Polarization Works

Light waves are electromagnetic waves, and like all transverse waves, they vibrate in all directions. So even as a light wave is traveling from the sun to your eye, the wave is vibrating in all directions, even directions perpendicular to the direction the wave is traveling in. Light waves that are vibrating in all directions are called unpolarized light, and can come from a candle, a light fixture, or the sun. Polarization eliminates these multi-directional vibrations, and creates a type of light wave where the vibrations occur in only one plane.

fly fishing, polarization, sunglasses, with without
(Josh Hutchins photo)

When you're fishing with polarized glasses, this means all those vibrating light waves coming from the surface of the water—the light we call “glare”—is reduced and we see mostly the light waves coming relatively straight into our retinas.

There are a number of ways to create polarized light, but it's most commonly done using a filter. In quality sunglasses, the filter is a layer of film sandwiched between glass or polycarbonate lenses. Since the film is inside the lenses, there's no way to scratch or remove the filter.

You can also sandwich a mirror coating between those lenses in the same way, and for the same purpose—durability.

A green, blue, or silver mirror can reflect additional light away from your eyes and reduce the overall visual light transmission rate of the lens.

fly fishing, polarization, sunglasses, with without, light spectrum, wavelengths, vibrating, waves
(Dennis Pastucha illustration)

Choosing a Lens Tint for Fishing

Sunglass tints can come in many colors, but in trout fishing they aren't just a fashion statement. They make a difference in your fishing. Gray-based tints are neutral. They reduce the amount of light coming to your eyes but otherwise don't alter your vision. Colored lenses like copper, amber, rose, and brown tints increase contrast to help you more easily identify a submerged weed bed, a drowned stump, or a brown trout under a root wad. I can't say copper is better than amber any more than I can generalize and say Cabernet Sauvignon is better than Tempranillo. Both are wonderful red wines. Copper and amber perform well in variable light when you have clouds and then sun and then more clouds because they strike a balance between shielding your eyes from the sun and enhancing your aquatic vision. Both tints have a red element that enhances your depth perception.

Rose tints enhance depth perception. Skiers wear them to pick out moguls and the 3D texture of the slope, and people wear them for driving and gaming to reduce fatigue related to hours and hours of eye strain. For fishing, I find rose tint lenses are inadequate for continuous bright sun. They work best for partly cloudy days and sight fishing on rivers with light-colored bottoms with a lot of sand or quartz and clean rock. In salt water, it's a good tint for cloudy conditions on a white sand bonefish flat. In rivers where the bottom is dark with algae and there are lots of weeds, copper and amber offer a distinct advantage.

fly fishing, polarization, sunglasses, lens tint, color, mirrors
(Dennis Pastucha illustration)


Yellow tints are popular with pilots, mountain bikers, long-haul truckers, and at the shooting range. They help pick out moving targets in foggy, hazy, or shaded conditions because they boost contrast more than any other tint. Polarized yellow lenses in fly fishing are specifically low-light lenses (discussed previously). Their visible light transmission (VLT) rates are very high, which means they allow a lot of light to pass. They allow you to sight fish on dark overcast days, in shaded canyons, forest streams, and in early morning and late evening—all times and places where fish prefer to feed. In my opinion these types of low-light lenses are both underappreciated and underused by most fly fishers, who only have sunglasses designed for bright sunny afternoons.

One more thing about lens tints: Be aware that the tint you “see” when the glasses are staring at you from that rack in the fly shop may be somewhat misleading. Manufacturers can put green or blue mirrors on copper- or amber-tinted lenses, so what you see from the outside might not be the actual lens tint.

Manipulating the Color Spectrum

As discussed previously in regard to polarization, light is an electromagnetic wave. The wavelengths of the light waves we can see range from 380 to 740 nanometers (nm). This is the visible light spectrum. For instance, a wavelength of 450 nm is blue, 550 nm is green, 650 nm is red, and so on. Every visible wavelength translates as a color to us.

We can't see most light waves. For instance, most ultraviolet light falls below 380 nm, light above 700 nm is called infrared, and there are x-rays and gamma rays—all are nonvisible electromagnetic waves. Short wavelengths carry a high amount of energy and can be damaging, while long wavelengths have low energy. That's why ultraviolet radiation can burn your skin, and infrared radiation is harmless.

Polarization helps us see fish by cutting glare, but perhaps the most important function of sunglasses is to protect your eyes, and filter out dangerous light waves. Every good pair of lenses should filter out UV light to protect your retinas from this dangerous radiation, just like you protect your skin with UPF 50 sun shirts or sunscreen.

fly fishing, polarization, sunglasses, visible light spectrum, high low energy, gamma rays, x-rays, UV, infrared, rapid waves
(Dennis Pastucha illustration)

UV light ends at about 380 nm, and from there up to about 430 nm we see the color violet. It's near to ultraviolet on the spectrum, and it's often called “high-energy blue” light because it also has the potential to harm your eyes if you combine it with long exposure and reflective surfaces such as sand, snow, and water. Sunglasses from quality brands like Costa, Magpul, Bajio, and others strive to filter out much of this high-energy blue light, along with all ultraviolet light to protect your eyes and cut haze to produce greater visual clarity and sharpness

But it's not only this type of damaging light they filter out. Costa and Smith both have their own secret elixirs in the form of proprietary filters that modify other wavelengths on the color spectrum. Costa's 580 lenses are their core technology, and these filter out yellow light at 580 nm (hence the name), which gives a boost to the appearances of blue, green, and red colors and produces better contrast and definition. Smith's ChromaPop lenses strive to enhance those three primary colors by eliminating the transitional wavelengths between red and green and between green and blue—specfically, wavelengths of 480 and 580 nm. Saying this another way, ChromaPop reduces yellow and cyan so you see mostly red, green, and blue.

These filters give each brand a very distinctive color palette. To me, Chrompapop works a lot like some Instagram filters, which we all know can appear very desirable to many people. It makes things look more dramatic and appealing than they really are, that's just the nature of filters.

Here's an important consideration when considering Smith ChromaPop versus Costa 580 lenses. ChromaPop technology is only available on polycarbonate or in the case of ChromaPop+, urethane-based NXT lenses. Costa 580 lenses are polycarbonate or glass. Glass offers the best optical quality—there is no debate here. There's a reason that glass is used for rifle scopes, binoculars, and telescopes.

Glass has the sharpest optical clarity, and glass is also more scratch-resistant than any other type of lens—it's much harder. Glass is also heavier. Some people report that in hot, sweaty weather, glass lenses slide down their noses more frequently or weigh on their temples.

Polycarbonate and NXT lenses are more impact-resistant, so while they might scratch rolling around on a boat deck, they won't shatter when you hit them with a 100 MPH Clouser Minnow. Magpul polycarbonate lenses exceed military combat eye protection (MCEP) and ANSI industrial safety standards, and the frames are nearly indestructible. They give you the same protection as safety glasses, but the optical acuity to spot trout in river.

Increasing your acuity and your ability to see below the surface doesn't just help you spot trout, it helps you see more of the world trout live in. And the more you see, the more you learn. Eventually, that all leads to catching more trout.

Ross Purnell is the editor of Fly Fisherman.

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Indigenous people and salmon have been intertwined for thousands of years in Bristol Bay, Alaska. Today, kids learn from...

How to Tie Dorsey's Top Secret Baetis Fly

Indigenous people and salmon have been intertwined for thousands of years in Bristol Bay, Alaska. Today, kids learn from...

Orvis Presents “School of Fish” Full Film

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