Costa Del Mar Fathom Sunglasses
Delivery and contents
The Costa Del Mar Fathom sunglasses were received promptly and safely. The display carton contained the glasses, glasses' case, and two pieces of product literature. One was a single small card describing the patented Wave 580 lens technology, and the other contained a wider array of information including minor technical notes and warranty information. Surprisingly, there was nothing indicating the best way to clean the lenses, although I intend to use a standard glasses cloth and cleaning solution as I do on my reading glasses. The display carton, emblazoned with an image of the glasses and the firm's motto “see what's out there”; while attractively produced, the box had minimal information on the glasses within. My only negative observation was that the lenses had some slight smudges, probably occurring during packing. They were easily cleaned.
Website and Warranty
Costa Del Mar offer a lifetime warranty against defects in material and workmanship. Incidental damage (normal wear, scratched lenses, broken hinges and accidental damage and misuse) are not covered, but “reasonable repair charges will be levied“ should such repair be required.
The website provides an overview of the company, founded in 1983 “by a group of hard core offshore fishermen and outdoorsmen.” There's a section devoted to conservation. The site is well designed, easily navigated, and detailed. It includes a very effective “find a dealer” system incorporating Mapquest, as well as a description of their technologies and materials, product line, etc. Incidentally, prescription sunglasses are offered.
Features and Design
I've always tended to be a bit careless about the sun, whether applying sunscreen or wearing sunglasses. However, as I've grown older I've grown a little wiser, and while I don't constantly wear sunglasses in the sun, I will do so in situations where the light's particularly intense. This includes climbs over tree line, when kayaking or otherwise on the water, skiing, and often when driving on bright days or when the sun is at a low angle (this last more for driving safety than eye protection). For the past couple of years I've used an old pair of Ray-Ban glasses that do not have polarized lenses (lenses designed to filter light of a particular polarization).
Why polarization is important in sunglasses
One of the main purposes of sunglasses is not merely to reduce the level of ambient light reaching the eye (and eliminate the harmful ultra-violet portion of the spectrum) but to cut glare. Glare generally occurs when the direct light of the sun is reflected off a surface e.g. water. The light from the sun is already polarized, in part by the atmosphere itself (this is related to the complex phenomenon of why the sky is blue).
The degree of polarization of light outdoors depends on the position of the sun. When light is reflected from a surface, any surface, it is further polarized, creating surface glare. Sunglasses primarily block that portion of light that is horizontally polarized (the primary component in most reflected light) thereby substantially reducing the level of glare.
The reduction in the light levels reaching the eye is considerable with polarized lenses. Those of the Costa del Mar glasses are extremely effective at eliminating horizontally polarized light. This is easily seen by looking into sunlit water both with and without the glasses. Without, little can be seen below the surface. With, and the underwater environment is suddenly visible!
The polarization material in the Costa Del Mar sunglasses is cast into the lens itself (rather than added as a surface laminate). To quote the website “the polarized film consists of polyvinyl alcohol molecules running in horizontal parallel chains. These chains act as a filter to block out light that bounces off horizontal reflective surfaces such as water, the highway, or the moisture in the air around you. This reflected light is 7 to 10 times brighter than ambient light and is commonly referred to as glare.”
The sunglasses lenses
Sunglasses further reduce the light level incident on the eye by the use of tints in the lens. A very dark lens, easily manufactured (think of smoked glass) will cut most of the ambient light. However, in doing so, most color and contrast will be lost. The trick for the manufacturer of sunglasses is to create a harmonious visual experience, with minimal distortion of color.
Costa Del Mar's Wave 580 lenses claim to filter one hundred percent of ultra-violet. But, beyond that, the product claim is as outlined below (quoted from Costa Del Mar's website).
“The WAVE 580 lens allows you to take in more of the light your eye should be seeing. Thanks to our proprietary WAVE Technology, this lens raises the red, blue, and green areas of the light spectrum to extraordinary levels, providing unmatched definition and color saturation. Simply put, you’re going to see like never before. The light near 580 nanometers, lying within the yellow region of the spectrum, is particularly difficult for the eye to process. Why? Excessive glare. Reducing this strong presence of yellow light controls this glare for incredible visual acuity.” This claim of enhanced acuity is interesting, and is very much something I will be testing.
The copper-toned lens, my choice for this product test, is stated to be “Designed to heighten visual acuity and color enhancement while delivering the brightest field of vision.” It is not particularly dark, nor is it mirror-coated, so when I'm speaking to someone with them on they can see my eyes. A personal thing, but I dislike sunglasses that completely hide the wearer's eyes.
Costa Del Mar's lenses are a complex sandwich of materials, according to their website information. Their glass lenses are made to withstand both an ANSI (American National Standards Institute) impact test (Z80.3:1996), and a more rigorous one the firm has designed. They are designed to be highly resistant to scratching and breakage (naturally, something that I will be examining over the duration of this product test).
While the exterior of the lenses seems to resist smudging from fingerprints, etc., the interior of the lens (apparently surfaced with a different material, with an almost iridescent sheen) shows fingerprints and grease-spots all too well. Still, this seems to have limited impact on the optical clarity, and the glasses clean easily with mild detergent and water or an optical cleaning cloth.
Frame design
The cast nylon frame is matte black, excepting that portion which sits against the ears, which are light gray. According to the website, this is Hydrolite, a rubberized material. It is formed with a slightly dimpled pattern, presumably to provide better friction against the ear, to avoid slippage. The frame is curved to conform and wrap around the face. The cast nosepiece projections sit squarely and snugly (but not uncomfortably so) on the bridge of my nose.
There are three holes, arranged in a vertical line, alongside (and just to the outside of) each lens. I'm unclear if these are stylistic or functional; they may be designed to help minimize fogging. The temples of the frame are not heavily sprung, but instead rely on the curvature of the frame for a snug fit. I find the fit comfortable (in fact, I'm reassured that they will not slide during vigorous exercise), though it is possible that this style might fit too tightly on some. My wife tried them and pronounced them so. A small and unobtrusive Costa del Mar logo in silver is attached to each temple.
The frame appears exceedingly sturdy. Co-injection, the method by which Costa Del Mar frames (made in Japan, according to lettering on the inside of the frame) are prepared, is a method for injecting different polymers into the same mold when casting. In this case, it enables the Hydrolite to be part and parcel of the frame, rather than an added coating.
The glasses do not fold up to be particularly small. This results in a rather large (and extremely sturdy) case, apparently a black cast plastic (lettered “Costa Del Mar”) with a strongly sprung hinge and felt interior. While this performs the job of protecting the glasses very well, it is considerably heavier than ideal, weighing in at nearly five times the weight of the glasses themselves. Given that the weight of the case is about equal to my stove (without fuel) and titanium mug combined, I may want to find a lighter one for backpacking.
On a final note, Costa del Mar means ”seacoast” in Italian, emphasizing the watery origin of the firm. Fishermen in particular need good polarized sunglasses!
Some preliminary tests
A new toy is no fun unless you get to play with it. In addition, I wanted to give a preliminary report on how these sunglasses work.
I was struck at first wearing (and remain so) at the transformation of visual effect. The word "hyperreal" comes to mind. If this term has some vaguely psychedelic connotations, so be it—they are not inappropriate to the world as viewed through the lenses! Not only is glare hugely reduced, but the world is a much greener place. Indeed, greens are almost breathtakingly intense, as are reds. The appearance of blue objects is not emphasized to the same extent, but the relative color value appears fairly accurate, despite the overt reddish tint of the copper lens. Whites (in full sunlight) are reasonably accurate (important for map-reading), but in shadow take on a coppery tint. Most flowers (I am an amateur botanist) don't seem to be distorted in color, but I had to take the glasses off to determine if an aster was white or lavender. The sky (in part because of polarization effects) is not a true blue but pinkish-blue, be the day ever so clear. I do find this a bit of a loss, but in aggregate the visual effect is pleasing and chromatically accurate.
I was curious to see what level of reduction of light levels the glasses achieved. To do this, I used my digital luxmeter (designed to test light levels for ergonomic applications). I covered the detector with card, leaving a central cut-out (this because the area of the detector is larger than that of one of the lenses). Placing the detector horizontally in the direction of highest glare (to the horizon beneath the sun) I took a reading of 50800 lux. With the sunglass lens in place, that dropped to 8000 lux. This represents a six-fold reduction in light levels (actually, slightly in excess of that). Coupled with the quality of vision experienced, that's a rather impressive statistic.
I also conducted a first field test. This was on Ashokan High Point, a 3000-foot (900-meter) peak that's about twenty minutes from my house. Temperatures were approximately 75 F (24 C), and the day was almost cloudless, with the bright September light that's common in this part of the world. I ascended the mountain in the mid-afternoon, bushwhacked along some cliffs until I intersected one of the summit paths, walked to the summit proper, watched the sun set (without sunglasses, naturally!), then descended by other trails. So far, it seems that the sunglasses will stay quite comfortably on top of my head when not in use.
I already feel that there is indeed some justification for the claim of enhanced visual acuity. We had a plague of caterpillars on these mountains in late spring and summer, which defoliated many trees. These put forth new leaves by late summer. With the sunglasses on, I could clearly distinguish (from a distance of a few miles) what was new leaf growth on the hills and what had remained untouched over the season. The new growth was much more verdant. Without sunglasses, the difference was not easily seen.
When bushwhacking, I found that it was easier to find clear lines through the heavy mountain laurel, as the green of the leaves stood out so sharply. This didn't stop me blundering through the occasional patch while ascending, but was certainly helpful. The first portion of the ascent follows a brook, and it was pleasant to be able to look deep into the waters without the distraction of surface glare.
On the minus side, because the lenses are fairly narrow, a certain amount of peripheral light was noticeable. This seems to be inherent to the design of the frames, not the fit. I didn't find this an issue on this hike, but it might prove to be if the sun were directly overhead. The glasses did remain perfectly stable throughout my bushwhack (more than could be said about me), and they protected my eyes from the occasional probing twig.
Proposed testing Strategy
Testing plan
I hike or kayak at least twice weekly, plus I take at least one backpacking trip of one or two nights each month, year round, with occasional longer trips interspersed. I also walk or cycle locally several evenings a week, as well as (snow permitting) enjoying x-c ski trips in season. In short, I'll be able to test the glasses at a wide range of light intensities, in a broad assortment of conditions and activities, I will additionally wear them for routine errands, driving, gardening etc.
Testing details
1. Effectiveness. First, how well do the glasses cut glare in the yellow portion of the spectrum that they are intended to block? Fifty percent of incident light in this range is eliminated, according again to the product literature. I'll test this claim subjectively (snow and water are both tough mediums for sunglasses).
Wearing them, I'll not only be gauging residual glare and any resulting eye fatigue, but the quality of color created by the light that is transmitted through the lens. Are certain portions of the color range distorted? Are the colors of leaves and flowers affected (as an amateur botanist, an issue of interest to me)? Do the lenses actually improve the quality of visual experience, as claimed? Do the glasses mask natural navigational cue such as shadows? This sounds like a minor issue, but I've found that some sunglasses definitely interfere with the sort of subliminal checking that most hikers do as they walk, especially off-trail.
2. Utility. Often when hiking, I will move from sunny, open spaces to deep shade. Is it necessary to remove the glasses under such conditions, or does the world still seem bright enough? Do the sunglasses interfere in any way with viewing the various gizmos (altimeter, GPS, compass) that I use when hiking? How about map-reading? Do they work well in conjunction with a magnifying lens when sorting out small details of terrain etc. on a topo map? Are contour lines etc. easily read?
3. Comfort. Though I have worn the frames for only a couple of hours, and have found them comfortable and attractive, that's a big difference from wearing them all day on a hike or backpack. Does the design of the frame keep the glasses correctly positioned on the face during intense physical activity, such as scrambling? Is the design of the frame such that the lenses can "breathe" and avoid fogging with sweat or ambient moisture? How well do the frames wrap my face; is there light visible at the periphery of vision. Am I able to push my sunglasses on top of my head when not needed and have them stay (my usual storage area for both reading and sunglasses when not in use over the day)!
4. Materials. Are the lenses resistant to scratching and wear (a very important point)? Are the co-injected composite nylon frames tough enough for the rigors of intense activity? Is there any tendency for them to distort (loosen up) over time? I've not worn nylon-framed glasses of any kind before. Will they withstand my klutziness, the occasional drop?
I thank BackpackGearTest and Costa del Mar for permitting me to participate in this highly enjoyable test.
