And eyepieces are not easy to design. Besides determining the magnification
of the scope (20 times the naked eye view up to 60x or even 80x), the eyepiece
has to yield as wide a field of view as possible so you can find and track the
bird easily and as much eye relief as is possible, so you can view comfortably.
A simple convex lens, like any magnifying glass, would work, but, at the powers
we ask for in a scope, it would produce a view of the image (and the bird) that
was obviously distorted (bent out of shape, especially at the edges) and very
narrow, and you would have to have your eye practically right up to the glass
to use it. Not to mention that all the effort and expense that goes into exotic
lens materials in the objective is wasted if the eyepiece introduces its own
false color.
Think of it this way: objectives use a lot of glass but they are relatively
simple things. They are made out of two kinds of glass (or sometimes some other
transparent material, like Fluorite), glued together in a single element. They
generally only have four shaped surfaces, four surfaces which have to ground
and polished to perfection. It is a relatively simple design problem. (A few
of the best objectives may have three pieces of glass in two elements and, therefore,
six surfaces.) To begin to match the quality of that objective, to balance power,
field of view, and eye relief, in a design that is well corrected for distortion
and color, the simplest eyepiece regularly in use in a spotting scope, and the
most common, is as complex as the best objectives. It has six shaped surfaces,
in two different elements, and employs two different kinds of glass. To optimize
power, field, eye relief and correction, you generally have to use up to seven
elements, several of which are made of two different kinds of glassin
complex designs that will have 14 to 24 shaped surfaces. Even if you set out
to design an eyepiece worthy of your objective, the cost of designing and producing
such a lens is often beyond what a manufacturer thinks the birder is likely
to want to pay. Makers know that big fancy objectives sell scopes. It is very
difficult to get most birders excited about eyepieces, or to convince them that
they might have to spend as much for the little eyepiece as they paid for the
whole rest of the scope.
Therefore, until recently, it has been the eyepieces that have limited the performance
of high quality spotting scopes. I have often said, here at BVD and elsewhere,
that if you are want a zoom eyepiece on your scope, you should shop for the
eyepiece that meets your needs, and then buy the scope it fits on. There are
still only a handful of truly usable zoom eyepiece available for spotting scopes.
There are a few that are good enough so that it is worth buying the scope they
fit on. (Okay, they are, in ascending order (saving the best for last): the
traditional zoom for the Nikon Fieldscopes; the Japanese Swarovski look-alikes
available for the Kowa, the Swift, the Celestron, the TeleVue Ranger, and now
the Bausch and Lomb Elite scopes; and, still the best, the Swarovski itself.
Leica redesigned their zoom eyepiece recently and improved it considerably,
about to the level of the Nikon zoom, but still not in the Swarovski class.)
There are a few other outstanding eyepieces out there that make the scopes they
fit on worth owning. The Leica 30 power wide field eyepiece is simply wonderful,
and the 30 wide for the Nikon Fieldscopes is not far behind. I havent
tested the fixed wide eyepieces for the Kowa, but I hear they are also fine.
Still, truly great eyepieces are few and far between.
All of this is
by way of introduction to the new 80mm ED spotting scope from Pentax. You see,
Pentax already produces a world class set of eyepieces, designed for amateur
astronomy. There is pretty general agreement in that community that the Pentax
astronomical eyepieces set the current standard, or at least equal the current
standard, for a useable combination of power, field of view, eye relief and
correction (all of which are just as important to an astronomer as they are
to a birder). They are currently the eyepiece to own if you are serious about
visual astronomy. These are no holds barred eyepieces, each one
the size of can of condensed soup, with lenses about the size of the objectives
in most mid-sized binoculars (in fact, if you took the glass out of the Pentax
eyepiece barrel, you could just about slide the whole Swarovski zoom, body and
all, right inside, and the Nikon zoom would rattle around inside even the smallest
of the Pentax light paths).
They cost, generally speaking, all by themselves, as much as a good pair of
binoculars too. Of course, they are astronomical mount eyepieces, made to fit
in the 1.25 inch standard astronomical focusers. They dont screw in or
twist on, they slide into an open tube and are generally locked in with a set
screw.
What Pentax has done is to design a spotting scope suitable for field use by
birders to fit these eyepieces. They started with a clever rotary locking mechanism
that allows you to just slide the eyepiece in and twist a large knurled ring
to lock it. They waterproofed the main body of the scope (the eyepieces were
already waterproof). They built an elegant, and fairly standard looking spotting
scope focusing mechanism. They added an very nice pull out sunshade and some
attractive armoring. Last but not least, they designed an excellent, long focal
length, 80mm ED objective to put up front. The result, with one of those big
eyepieces on the business end, is relatively large scope, but they have managed
to keep it within the weight range for other 77-82mm scopes.
Was it worth the effort? Optically, the new Pentax scope, with its fixed power
eyepieces, is noticeably superior to any other scope currently on the market.
Yes, you read that right. The at 30 to 40 power, the Pentax scope equals the
resolution of the previous Reference Standard for all scopes, the TeleVue Ranger,
and it has a notably brighter, more contrasty image with more intense colors
and sharper color separation. The field of view and ease of use has to be seen
to be appreciated. These eyepieces are everything the astronomers have claimed.
The field is wide and open. The eye relief allows an exceptionally easy view
from behind the scope. It is not like looking through a scope at all. It is
like walking right up to the bird and looking at it through the highest quality
magnifying glass you have ever seen. And did I say the image was bright? The
huge light path of these eyepieces, beginning with the 1.25 inch tube, optimizes
the light gathering ability of the 80mm objective. You suddenly realize that
most other scopes are being stopped down from the true objective
size by the tiny eyepiece barrels we use on them.
So okay, Pentax has managed to create a spotting scope worthy of their world
class fixed power eyepeicesbut they didnt stop there. New with this
scope is the first waterproof zoom eyepiece. It is hugea size
bigger even than the fixed power eyepieces, and, again, features a light path
the size of the 1.25 inch mount. While it doesnt have either the field
of view or the eye relief of the fixed power eyepieces, it certainly equals
or exceeds the field and eye relief of the zooms available until now. Combined
with the 80mm ED objective of the scope, it provides an amazingly bright, amazingly
sharp, amazingly detailed view from 20 to 60 power: the best overall performance
I have seen so far in any spotting scope with a zoom eyepiece. It has just enough
eye relief so that I can see the whole field at all powers. This zoom is a truly
impressive accomplishment.
Impressive as the zoom is, dont forget to take a look at the view through
the fixed power eyepieces. The 30x eyepiece is bright enough and sharp enough
so that you would rarely need higher powers, and so easy to use that you might
not ever want to take it off.
Last but not least, Pentax has managed to put this scope together at price that
is certainly competitive with the other major players in the premium scope market.
In fact,
the combination of fairly conventional spotting scope handling, reasonable weight
and excellent balance, a measure of field durability and weatherproofness, a
big bright objective, reasonable value, and what are simply the finest eyepieces
currently available for any scope on the market make the Pentax scope the current
Reference Standard, not only for conventional spotting scopes, but for all scopes.
I have no hesitation in saying the Pentax scope is currently the best birding
scope you and buy at any price, and, given its price, might even be considered
a bargain.