Kowa TSN-773 Spotting Scope
In the beginning, there was darkness (which is great for owling but notably
poorer for passerines!). Then, in about 1952, Kowa invented the Z-prism
and the modern spotting scope was born. Kowa held top position in the
spotting scope market until well after their patent ran out, and the other
optics makers began to catch up. Since then, some of the competitors have
replaced Kowa at the top. But with the introduction of the TSN-770 and
-880 scope lines, Kowa is clearly back on top. The TSN-770 series is the
smaller of the two newest scope lines from Kowa. We've reviewed scopes
before. We've reviewed Kowa scopes before. We've never seen anything like
this scope before! We received the 88mm angled fluorite model TSN-883
("Prominar", for those of you familiar with Kowa terminology)
for review from Kowa and the eXtra-low Dispersion 77mm TSN-773. Since
our tests, we received a TSN-884 whose optics were identical to the 883.
The TSN-883 and -884 are reviewed in another article.
We took both scopes out into
the field along with several very fine scopes from other manufacturers.
Thanks to a brief preview, we fully expected the TSN-883/884 to come out
on top. What we didn't expect was that the TSN-773 would finish second.
Although the 77-mm Kowa was matched against scopes of 80-82 mm, the new
Kowa was still detectably brighter, a difference that became more and
more apparent as the evening light began to fade. The image brightness
and clarity were really impressive. The flat-field performance is stellar,
as the image remains perfectly sharp right to the edge of the field. When
you pan across the field with the scope, it’s like moving a picture.
In fact, it’s so beguiling that you fail to notice it because you
get so distracted by what you’re seeing. In effect, the scope becomes
invisible, and you forget that you’re using it. There was the a
hint of color-fringing at the field edge, and this was slightly more pronounced
on the 773, but you really had to look specifically for this in order
to observe it. It is so minor that we’re really only reporting it
so you know we’re being honest.
The objective lens on the TSN-773
is eXtra-low Dispersion (XD) glass and the lenses are made of environmentally
friendly eco-glass. As with the larger models, the 773 lenses are fully
multi-coated with Kowa's C3 coatings that are made of dielectric materials
instead of the more common silver or aluminum. Kowa claims 99% or higher
light transmission. While we don't have equipment to measure that, the
superb light transmission is obvious in the viewing. As is expected in
scopes of this quality, the body is sealed and nitrogen purged to be waterproof,
and internally dustproof and fogproof. Less expected is the fact that
the individual eyepieces are also sealed the same way.
The TSN-773 is a very compact
12.5 inches long (without eyepiece) and weighs less than 3 lbs (46.9 oz.).
This is at the light end of the spectrum for 77-to-82-mm scopes, due in
part to its magnesium alloy casing. The lens hood pulls straight out,
and as always, we strongly recommend using it. In one of the few shortcuts
they took, Kowa provided only a shallow double groove on the hood to enable
sighting on a target. Again, this is a minor quibble.
in passing, the minimum close focus on the TSN-773 is 16.5 feet, about
average for a high-powered scope. Then again, the whole point of a spotting
scope is viewing distant objects. Another distinctive feature of this
scope is the dual focusing mechanism. Other manufacturers have had this
innovation for years, but Kowa has added it on the new models. In the
new Kowas, this mechanism was nicely executed. There are two focusing
knobs side-by-side. The larger knob nearer the eyepiece is for coarse
focus, while the smaller knob is for fine focus. The knobs are placed
so that the fine focus sits comfortably under the middle finger while
the index finger is positioned for the coarse focus. The 773 goes from
minimum close focus to infinity in two full turns of the rough focus knob.
The mechanism is so smooth that when focusing, the image remains rock
steady. With a helical focusing mechanism, it is virtually impossible
to adjust the focus without causing the image to tremble. Whether or not
this is significant is debatable, but the fact that it’s impressive
The 770 series scopes use the same eyepieces as the 880 series scopes,
so we have already reviewed them and haven’t really got anything
new to say about them. The same also holds true with regard to digiscoping
adaptors and attachments. Please refer to that
review for a discussion of the eyepieces that we looked at on these
scopes. One point that deserves updating with respect to these was that
in that review, we noted that the eyecup adjustment frequently came unscrewed
while we were adjusting it, because the digiscoping adaptor is designed
to fit in the place occupied by the eyecup. We subsequently learned that
giving it a small amount of torque at the end of twisting it in would
solve the problem. At the time of the 880 series review, the digiscoping
accessories were not regularly available. Those parts are now all available.
The tripod mounting foot has a removable threaded bushing that allows
the user to select between 1/4-20" and 3/8" mounting screws,
which gives the user more choices among tripods. The tripod mounting foot
sits on a rotating collar, held in place by a setscrew. When loosened,
the scope rotates freely in either direction, with 6 click-stops pre-set
in the most logical positions for field use.
While not initially available,
Kowa has finally released the cases for the 770s and 880s. The case is
has a water resistant green cordura nylon outer shell, thick foam rubber
padding, and lined with soft, smooth nylon. There is one zipper that opens
the flap over the objective lens, one on the bottom for letting the mounting
foot through, and one that starts underneath the scope's prism and goes
around the eyepiece almost to the objective flap on the top. Velcro patches
on the flaps and under the objective keep the flaps in place during use.
We recommend purchasing the case because there is no armoring on the scope
body, and it's $60 cost is inexpensive insurance for protecting this investment.
And it is a significant investment: the TSN-773 body may be found for
as little as
$1,600.00, while eyepieces
for the 25-60x wide angle zoom eyepiece,
for the 25x long eye relief eyepieces. The 30x eyepieces have been discontinued.
Is the Kowa TSN-773 scope the
finest scope we have looked through to date? Not quite. Its big brothers,
the TSN-883 and TSN-884 can claim that title for now. However, if you
prefer to save $850 and about a half a pound, you need look no
farther. Looking through this scope in the field will change your opinion
about what kind of resolution, brightness, and clarity of image are possible
in a 77mm spotting scope.
TSN-773 Spotting Scope