Tom Lester
Every so often there is a rumor in the industry that a company has produced a new line of binoculars that is supposed to redifine the state-of the art in sports optics. To be state-of-the art, a binocular must have exceptional image clarity and resolution; superior brightness; a wide field of view, and true color accuracy, free of aberrations. However, that's not enough. It must also be lightweight, easy to handle, focus smoothly and quickly, and have sufficient eye relief for viewers with and without eyeglasses.
By any measure, this is a tall order to fill. Hence, true state-of-the-art binoculars don't come along very often, but when they do it can be an eye-opening and breath-taking experience.
So, when I heard about the Zeiss Victory 8x42 T*FL binocular with its Advanced Optics System (AOS) and fluoride (*FL) lens elements, I figured this is one binocular that I'd really like to put through its paces under field conditions to see if it really deserves all the publicity.
After spending a considerable amount of time in the field chasing warblers at dawn, tracking down skittering shorebirds in bright sunlight and glassing the treetops for hawks at dusk, here's what I think of the Zeiss 8x42 T*FL binocular.
Comfort, Handling and Focus
At just over 26 oz., the roof-prism Zeiss 8x42 T*FL is exceptionally lightweight and well-balanced for a full-sized binocular. It has a glass-fiber reinforced polymer body shell with a durable rubberized armor coating. The body is nitrogen-filled and sealed, providing excellent water, fog and dust proofing (JIS Class 6).
The binocular has a slightly tapered and ribbed body making it comfortable to hold, even for long periods of time. The ribbing and the rubberized armor coating also make the binocular easy to grip in any weather conditions.
Collimation in the 8x42 Zeiss T*FL binocular is excellent, resulting in effortless viewing; free of eyestrain, headaches or inferior images.
Focusing is smooth, owing to the binoculars' large ribbed columnar focus barrel that adjusts rapidly from close focus to infinity in just one and a quarter turn. In fact, focusing can be so quick that one can occasionally over shoot.
Diopter adjustment is easy using the pull-out/push-in locking cap located at the end of the focus barrel. Simply pull out the cap exposing the diopter correction column, then twist to the appropriate setting and snap the cap back into place. Settings can quickly be determined at a glance by reading the +/0/- diopter markings located on the cap.
The minimum focus distance for the 8x42 T*FL binocular is an exceptional 6.5 feet (!), the shortest of any full-sized binocular on the market. This feature is particularly nice for close-in birding or when viewing other critters at close range.
Eye Relief, Field and Depth of View
The Zeiss 8x42 has plenty of eye relief to satisfy all viewers (16mm). As well, the twist and lock eyecups can be easily adjusted into one of four positions, allowing a rapid change in eye relief as required.
At 7.7 degrees, the field of view in the 8x42 *FL is quite wide, measuring 405 feet at 1000 yards. This broad field of view is particularly useful to bird watchers when surveying a large raft of ducks or when searching for an elusive bird in a dense thicket. Hunters too would find this wide field of view useful in glassing large open areas for game.
As for depth of field (the ability to view objects in space from foreground to background without having to adjust the focus), the Zeiss 8x42 T*FL is the equal of any binocular I've used with the possible exception of the Swarovski 8.5x42 which is only marginally better.
Resolution and Image Quality
Zeiss has long enjoyed a reputation of creating some of the finest optics in the world, and their line of T*FL binoculars is no exception.
A key optical ingredient in the Zeiss T*FL line of binoculars is the Advance Optics System (AOS) enhanced by special extra-low dispersion fluoride glass lens elements and the proprietary Abbe-Koenig image-erecting prisms.
The fluoride glass has the effect of controlling secondary light spectra, thereby reducing any hint of color fringes and aberrations to an absolute minimum. When the AOS is combined with the Zeiss' Superachromat objective, the 8x42 T*FL binocular generates an image that is remarkably clear; with state-of-the-art resolution, contrast and color accuracy; all key features when trying to distinguish between subtle variations in color patterns or wing barring in birds.
The Abbe-Koenig prisms found in the Zeiss T*FL binoculars provide up to 5% more light transmission than conventional Penchan designed prisms due to differences in coatings. As a result, average light transmission in the T*FL binoculars is over 93% dropping only marginally at dusk and dawn, the highest and brightest of any binocular in its class.
Additionally, Abbe-Koenig prisms are thinner than many other prism designs, thereby further reducing overall binocular weight.
Finally, the Zeiss P* star anti-reflection prism coatings provide phase correction which promotes high image contrast and resolution even when viewing silhouetted or back lit images against a bright background.
Overall Field Impressions
The Zeiss 8x42 T*FL binoculars performed extremely well in all field conditions. I was particularly impressed by its rugged, lightweight, weather proof construction.
When used with my shoulder harness, the binoculars are so lightweight I hardly knew they were there. In chilly conditions, where gloves are a must, the ribbed body and focus barrel provided a little extra grip-- a nice feature when you're shivering cold!
As most birders or hunters will agree, the true test of optical excellence in a binocular is to provide maximum image clarity and resolution at daybreak or nightfall. In my field assessments, the 8x42 T*FL binoculars consistently generated an exceptionally bright, clear image with lots of resolution and contrast whether it be at mid-day or at dawn and dusk when ambient light was minimal.
Viewing color images at 25 and 100 yards, I found the binoculars to be color neutral and very accurate, another key feature when examining subtle color differences in closely related species of flycatchers and shorebirds or when trying to distinguish between duck species in eclipse plumage.
As well, there was no evidence of chromatic aberration even when viewing high-contrast images such as a black crow against a bright sky. Image sharpness throughout the field of view is excellent, even at the margin. However, when looking at targets consisting of black and white horizontal and vertical lines, I did note a very slight amount of spherical aberration at the extreme margins of the image.
I also spent some time in the field comparing the Zeiss 8x42 T*FL to one of my favorites, the Swarovski 8.5x 42 binocular. I was particularly interested in comparing the binoculars for their depth of field, an optical feature that is superlative in the Swarovski.
I found the Swarovski to yield a slightly deeper field of view than the Zeiss 8x42 without having to adjust the focus wheel. For example, when focusing on a congregation of plovers with the 8x42 Zeiss T*FL, I could clearly view objects within an 8-10 foot depth of field without adjusting the focus. Whereas with the Swarovski, I could view objects within a 12-14 foot field depth without adjusting the focus. This difference may seem slight but it's noticeable when surveying large flocks of ducks or conducting tedious day-long bird counts on large congregations of shorebirds.
Other comparisons between the Zeiss and Swarovski binoculars included: color (Swarovski appears slightly warmer in coloration), focus (the Swarovski is a bit slower to focus, requiring more turns of the focus wheel to go from close focus to infinity), resolution (the Zeiss had a bit more resolution under low light conditions), contrast (equally good) and weight (the Zeiss being a few ounces lighter).
Fortunately, I also had the opportunity to spend some time in the field with the 7x42 and 10x42 binoculars in the Zeiss T*FL line. As expected, both performed equally as well as the 8x42 T*FL model, although each has its own unique attributes.
Overall, the 7x42 T*FL exhibits the same excellent optical characteristics of the 8x42 model. However, the 7x42 T*FL generates a significantly wider and absolutely breath-taking field of view of 8.6 degrees (450 feet @1000 yards.). Also, the combination of the large 6mm exit pupil and 42mm aperture makes the 7x42 a bit brighter than the 8x42 model. The extra brightness makes the 7x42 *FL model a particularly good choice for birding in low light conditions such as in dark forested areas or where overcast skies are prevalent and for young birders, whose eyes can take full advantage of the large exit pupil.
For those wanting some extra magnification to get that last bit of image detail or to view objects at great distances, the Zeiss 10x42 T*FL binocular offers superb optical performance.
With its smaller 4.2 mm exit pupil, the 10x42 T*FL model is somewhat less bright and has a smaller field of view (330 feet @ 1000 yds) than the other two *FL models. However, its exceptional ergonomics and light weight make the 10x42 binocular easy to hold steady. This feature significantly reduces the jittery image often associated with higher power binoculars.
Conclusions:
As you may have guessed by now, the rumor mill is indeed correct. Zeiss has created a true state-of-the-art series of binoculars with its Victory T*FL lineup, led by the outstanding and versatile 8x42 T*FL model.
The combination of world leading optics utilizing the Advanced Optical System and fluoride lens elements combined with the exceptional ergonomic design and rugged durability places the 8x42 T*FL binocular at the leading edge of sports optics in its class.
Is it better in every respect than any other binocular in the world? Not quite. But it's pretty darn close!
Simply put, the 8x42 T*FL, in my view, is the finest all-round birding binocular in the world today. In fact, depending upon the primary use, any of the Zeiss T*FL binoculars will satisfy the most discriminating viewer.
And so, the Zeiss 8x42 T*FL richly deserves recognition as the new BVD Reference Standard for a full-sized binocular.
Happy Viewing!