Archive-name: birds-faq/optics
Last-modified: 18 November 1993
Posting-frequency: monthly


This is the monthly posting of frequently asked questions about optics
for birding. Send any comments, suggestions, or additions to Ed
Matthews (edm@verdix.com).

Summary of Changes Since Last Publication
=========================================

Sorry kids; none.  Christmas break for me.

Table of Contents
=================

1. General Advice
2. Common Questions About Optics
2.1 What does 7x35 mean?
2.2 How do I chose a magnification level?
2.3 What about field-of-view?
2.4 What about rubber armoring?
2.5 What about eyeglasses?
2.6 What are the pros and cons of fixed versus zoom eyepieces for scopes?
2.7 What about 45 degree eyepieces?
2.8 How about taking pictures through a scope?
2.9 How close should I be able to focus?
2.10 Which inexpensive binoculars would you recommend to a beginner?
2.11 What does the endorsement of the National Audubon Society mean?
3. Supports
3.1 Tripods
3.2 Monopods
3.3 Finn Sticks
3.4 Shoulder Stocks
3.5 Window Mounts
4. Ratings
4.1 Better View Desired (Scopes and Binoculars -- August 1993)
4.2 Living Bird (Binoculars -- Autumn 1992)
4.3 British Birds (Owner Survey, Binoculars and Scopes, July 1991)
4.4 Living Bird Quarterly (Scopes -- Autumn 1990)
5. Sources for Optical Equipment
6. Useful Reference Material
7. Contributors

1. General Advice
=================

Don't buy any optical equipment without first field testing it,
especially if you wear glasses.  Go to a popular birding spot and ask
to try various scopes and tripods.  This is the only way to determine
individual preferences such as weight, balance, and desirable
magnification level.

Owners of most tripod brands report loose parts and some report rust.
Tripods, like any other equipment with moving parts, require periodic
tightening and cleaning.

A good strap on a scope or binoculars increases comfort dramatically.
The new breed of neoprene straps from OP/TECH come highly recommended.
They are available from most optics merchants and camera shops.

2. Common Questions About Optics
================================

2.1 What does 7x35 mean?

The first number is the magnification.  The second is the size in
millimeters of the objective lens.  The objective lens is the large lens
through which the light first enters the binocular or scope.

Objective lens size is a key factor in how much light enters the
instrument.  To determine the relative brightness of an instrument, divide
the objective lens size by the magnification (e.g., 35mm/7 = 5mm).
Optical instruments cease to be brighter when this measure, called the
exit pupil, exceeds the size of your pupil.

Apparently, as you age, your pupil does not dilate as much as when you are
younger.  By age 40, your pupil dilates to a maximum of about 5mm.  Buying
binoculars with a larger exit pupil is a waste of money.

If exit pupil were the only factor in brightness, your choice would be
easy.  However, the quality of the glass and its coatings play a large
part in determining brightness.  You will find that good 10x40 (4mm exit
pupil) binoculars are generally brighter than cheap 7x35 (5mm exit pupil)
binoculars.

Birders who try to see pelagic birds on an active ocean find their
binoculars move around a lot with respect to their eyes, especially if
they wear eyeglasses.  An over large exit pupil helps keep a bird in view
as they bounce around on the tossing deck, with the binoculars in one hand
and the other hand holding onto the boat itself.

2.2 How do I chose a magnification level?

The lower the magnification, the shorter the effective range of the
instrument.  As a payoff, you get a brighter image and a wider field-
of-view.  The higher the magnification, the harder the instrument
is to hold steady, the less bright the image, and the narrower the
field-of-view.

For binoculars, common magnification levels are 7, 8, and 10.  Good
quality optics are generally more important than magnification level.

For scopes, the most popular range is between 20x and 40x.  Distortion
from heat shimmer becomes a big factor over 40x.  Lower than 20x limits
the useful range of the scope.

2.3 What about field-of-view?

Binoculars typically have a label that expresses field-of-view (FOV) in
degrees and/or width at a given distance.  Expressed in degrees, FOV means
that portion of a circle (360 degrees) visible at a certain distance.

In the US, we calculate FOV at a distance of 1000 yards.  Typical FOV at
1000 yards ranges between 5 and 8.5 degrees, which corresponds to a FOV
263 feet to 446 feet wide.

The wider the FOV, the better the instrument for picking up motion in the
distance.  Other things being equal, wider FOV is generally better than
narrower FOV. Of course, other things seldom are equal, and you generally
must pay for wide FOV some other way: lower resolution, lower
magnification, less eye relief, greater weight, or higher cost.

In many cases, the actual FOV may be markedly different
than what the manufacturer indicates it is.

The easiest way to compare the FOV of binoculars having different
magnification is to look at the "apparent FOV".  This is the actual FOV
times the magnification.  Typical values range from 45 to 75 degrees with
most being between 50 and 65.

2.4 What about rubber armoring?

Binoculars and scopes are sometimes clad in rubber -- this is known as
rubber armoring.  Rubber armoring provides protection against corrosion
and dirt, helps cushion blows to the instrument, and gives a less
slippery surface to grip.  Armoring adds a little weight and may
require maintenance with a rubber preservative.  Many feel rubber
preservatives leave a greasy feeling.

2.5 What about eyeglasses?

People who wear eyeglasses often have trouble with scopes and
binoculars.  DO NOT BUY BINOCULARS OR SCOPES WITHOUT TESTING THEM WITH
YOUR GLASSES. Try several models with your glasses.  The Bausch & Lomb
Elite scopes with fixed lenses are excellent for birders with glasses.
Several scopes have optional long-relief eye pieces, which you will
need if you wear glasses. Look for eye relief of at least 15mm.

2.6 What are the pros and cons of fixed versus zoom eyepieces for scopes?

Fixed magnification eyepieces tend to give a crisper and brighter image. 
Zooms can be useful, but unless you spend a lot of money, can be of lesser
quality than fixed lenses.  Some birders prefer interchangeable fixed lenses
(e.g., a 25x lens and a 40x lens) to a zoom.  Zooms on the expensive scopes
(e.g., Kowa) are excellent.

2.7 What about 45 degree eyepieces?

They are not hard to use when you get used to them and are preferable for
watching flying birds, especially those migrating raptors.  If you're tall,
you can use a slightly smaller tripod.  If you're short, the lower scope
gives more opportunity for something to get in your way.  A drawback is that
the eyepiece is angled up into the rain and blowing dust.

2.8 How about taking pictures through a scope?

General consensus is that if you want to take professional pictures, don't
use your scope.  It requires a really steady (heavy) tripod and the combo
of scope and camera is heavy and awkward.  Focusing is difficult, and
close focusing and aperture adjustment are not generally possible.

The following is paraphrased from the Canon EOS FAQ on rec.photo by Bob
Atkins (thanks, Bob!):

  In general, scopes are too slow and their focal lengths are too long.
  The longer the focal length, the steadier you must hold the lens and the
  more atmospheric effects will degrade the image. The only scopes capable
  of yielding high quality images are the fast, short focal length,
  apochromatic refractors. For example, TeleVue makes a 500mm f5
  apochromatic telescope using Fluorite lens elements. It makes a very
  good lens (manual focus, fixed aperture), but costs $1700, weighs 10lbs+
  and is about 36" long. While not easy, you can use it in the field with
  a heavy tripod.  Its performance as a lens is similar to the best
  telephoto lenses; however, it has several drawbacks.  It has no AF; you
  cannot stop it down; and it is big, heavy, and awkward.

2.9 How close should I be able to focus?

[From _The Complete Birder_, Houghton Mifflin, Boston, 1988, by Jack Connor]

"Binoculars that focus near at hand are essential for successful
woodland birding.  In fact, a number of problematic pairs of small
birds can be visually separated only at close range:  Carolina and
Black-capped Chickadees; Sedge and Marsh Wrens; Mourning and
Connecticut Warblers; Le Conte's and Sharp-tailed Sparrows; Cassin's
and Botterei's Sparrows; and many others.

Fortunately, close focus is one binocular feature that can be tested in
a store. Find the closest line or spot on the floor you can see sharply
through the binoculars, then count your paces as you walk to it.  For
an accurate test, first adjust the dioptric-compensation ring for the
difference in strenghts of your two eyes. How far you need to turn that
ring and how much play remains in the center-focusing mechanism will
determine how closely you can focus.

A close-focus range of 15 to 18 feet is the least you should accept. If
you can't look at birds closer than that, you'll find yourself stepping
backward into cat briars and poison ivy to try maintain distance.

If you are a particularly dedicated sparrow and warbler chaser, you're
likely to be happier with a minimum range of about 10 feet.  Depending
on your eye strength, binoculars can be found with close-focus ranges
down to 6 feet...."

2.10 Which inexpensive binoculars would you recommend to a beginner?

Many people consider the Bushnell Birder 7x35 a great buy at $75 or under.

2.11 What does the endorsement of the National Audubon Society mean?

The NAS has licensed their logo to at least one manufacturer and the logo
appears on certain optical products. The appearance of the logo does not
constitute any endorsement by NAS.  The logo presumably indicates that the
product is targetted at birders; however, it does not mean that it is any
better than competing products from other manufacturers.

3. Supports
===========

Supports for birding with binoculars and scopes come in several forms:
tripods, monopods, Finn sticks, shoulder stocks, and window mounts.

3.1 Tripods
===========

Owners of most tripod brands report loose parts and some report rust.  Tripods
are like any other equipment: they do require some preventative maintenance.
The large majority of readers use one of two tripods, the Bogen 3021 or the
Davis & Sandford RTS. Gitzo also makes fine tripods which are popular in
among professional photographers.

Here's a tip for all you tripod thunkers. To minimize the thunk of the
tripod when you open it, hold it horizontally, then pull out and lock the
legs. The birds and your fellow birders will appreciate it.

Bogen (Manfrotto outside the United States)

[Editor's note: it is not clear whether Bogen model numbers correspond to 
Manfrotto model numbers.]

Model 3021 is most popular with birders; lesser models are not sturdy
enough; larger models are overkill.  With the micro-fluid head, it weighs
about eight pounds without scope, so it requires a strap.  However, the
weight makes for a steady scope in the wind.  The quick release plate for
the micro-fluid head is nice, especially for switching between scope and
camera.  The quick-release leg levers are handy, but take some strength to
operate and have a reputation for coming loose. A few birders report tripod
collapse as a result. The levers are good at catching twigs, hair, and
binocular straps. Legs can open noisily if not careful. Good height for tall
birders.  Replacement parts are readily available.  With proper
maintenance, owners are generally happy with this tripod.

Davis & Sanford (Tiffen)

Model RTS is no frills, solid, lightweight (4.75 lbs), and fast to
open because of its twist-to-unlock legs.  Is not as tall as Bogen
3021. [Editor's note: I'm 6'3" and the Bogen is a better fit.]  Owners
find this tripod plenty sturdy even with heavy scopes.  The pan-head is
very simple -- twist the pan-arm to loosen and twist back to tighten in
place.  The quick change screw for quick release mounting is nice.
Owners seem to be universally happy with this tripod.

Gitzo

While primarily aimed at professional photographers who need stability for
monster lenses (400mm+), Gitzo tripods have found some favor among
birders.  Model 341 (the Inter Pro Studex Rapid) is solid (at 7 lbs.),
good for tall birders, and well built.  The Bogen fluid head fits this
tripod.  Drawbacks are that it is expensive (around $300) and long (29")
when collapsed.

3.2 Monopods

A monopod is not a replacement for a tripod.  However, a monopod is an
option when weight and bulk are factors.  When I travel by air, I pack a
monopod, scope, and binos into my briefcase along with the appropriate
field guides, leaving my hands free for luggage and portable computer.
Monopods lack stablity (especially in the wind) and have only limited
height (I perch mine on a rock where possible).
 
3.3 Finn Sticks

[TBD]

3.4 Shoulder Stocks
 
A shoulder stock is device similar to the stock of a gun, on which you
mount a scope or camera.  Some people prefer a shoulder stock for its
mobility and portability.  They are excellent for following the path of a
moving bird; however, the scope is only as steady as your arm and your arm
will get tired quickly.

3.5 Window Mounts

Several manufacturers make scope mounts that slide over and fasten to a
car window. These are useful for birding impoundments and fields
accessible by car.  Although very handy, they transfer all vibrations from
the car to the scope, so you have to turn off the car and they also can
take infuriatingly long to attach to the window. An alternative solution
is a small (usually homemade) bean bag that rests on top of the window (or
car roof, boulder, limb).  See the Dec 1992 _Birding_ for more details.

4. Ratings

4.1 Better View Desired (Scopes and Binoculars -- August 1993)
==============================================================

The following selections come from the August 1993 issue of _Better View
Desired_, Stephen Ingraham's newsletter devoted to evaluating birding
optics.  These selections are in two categories: Reference Standard,
products that set the performance standard for their class; and, Best Buy,
products with outstanding performance at an affordable price.

Reference Standard:
    Mid-sized Binoculars          : Optolyth Alpin 8x30
    Full-sized 7x & 8x Binoculars : Zeiss 7x42
    High-power Binoculars         : Celestron 9.5x44ED
    50-60 mm Spotting Scopes      : Nikon Fieldscope ED
    70-80 mm Spotting Scopes      : Tel Vue Pronto
 
Best Buy:
    Mid-sized Binoculars          : Celestron Ultima 8x30
    Full-sized 7x & 8x Binoculars : Swift Ultralite 8x42
    High-power Binoculars         : Swift Ultralite 10x42
    50-60 mm Spotting Scopes      : none
    70-80 mm Spotting Scopes      : Celestron S80+

Product of Special Merit          : Swift Audubon 8.5x44

4.2 Living Bird (Binoculars -- Autumn 1992)
===========================================

[Thanks to Sid Johnson for providing the softcopy of this report that appeared
in "Binocular Quest", _Living Bird_, Autumn 1992, authors T. Culver and H.
Gerhart.]

                                Suggested
                                   List   Prism
         Model                    Price    Type       Armor?   Warranty

Over $800:

* Bausch & Lomb Elite 10x42       $1,956   Roof        Yes   Limited Lifetime
* Bausch & Lomb Elite 8x42        $1,900   Roof        Yes   Limited Lifetime
* Bausch & Lomb Elite 7x36        $1,704   Roof        Yes   Limited Lifetime
* Leica Ultra 10x42 BA            $1,590   Roof        Yes   Lifetime
* Leica Ultra 8x42 BA             $1,590   Roof        Yes   Lifetime
  Nikon Classic Eagle 8x40 DFC    $1,232   Roof        No    25-year Limited
* Zeiss Dialyt 10x40 B/GAT        $1,250   Roof        Yes   Lifetime
* Zeiss Dialyt 7x42 B/GAT         $1,215   Roof        Yes   Lifetime

$500-$800:

  aus Jena Luxus 10x40              $775   Roof        No    Limited Lifetime
  Bausch 7 Lomb Custom 10x40        $528   Porro       Yes   Limited Lifetime
  Nikon Execulite 9x30              $567   Roof        No    25-year Limited
* Nikon E CF HP 8x30                $512   Porro       No    25-year Limited
* Optolyth Touring 10x40            $608   Roof        Yes   Limited Lifetime
  Swift Audubon 7x35                $600   Roof        Yes   Lifetime

$200-$500:

  Celestron Ultima 10x42            $350   Porro       No    Limited Lifetime
  Celestron Ultima 8x32             $350   Porro       No    Limited Lifetime
  Minolta Weathermatic 7x42         $406   Roof        Yes   25-year Limited
  Optolyth Alpin 10x40              $360   Porro       Yes   Limited Lifetime
  Optolyth Alpin 7x42               $360   Porro       Yes   Limited Lifetime
  Optolyth Alpin 8x30               $298   Porro       No    Limited Lifetime
  Pentax DCF 8x42                   $375   Roof        No    Original Owner
  Pentax PCF 7x50                   $220   Porro       No    Original Owner
  Pentax PCF 7x35                   $200   Porro       No    Original Owner
  Redfield WP 10x50                 $407   Roof        Yes   Limited Lifetime
  Redfield WP 7x35                  $361   Roof        Yes   Limited Lifetime
  Swift Audubon 8.5x44              $399   Porro       No    Lifetime

* Swift Ultra Lite 8x42 ZWCF        $345   Porro       Yes   Lifetime
  Swift Egret 10x42 HCF             $288   Roof        Yes   Lifetime

Under $200:

* Bushnell Birder 7x35               $75   Porro       No    Limited Lifetime
  Minolta Standard 7x35             $141   Porro       Yes   25-year Limited

Compacts:

* Bausch & Lomb Custom Compact 7x26 $457   Rev. Porro  No    Limited Lifetime
  Leica 10x25 BCA                   $645   Roof        Yes   Limited Lifetime
  Leica 8x20 BCA                    $615   Roof        Yes   Limited Lifetime
  Minolta Pocket 7x21               $137   Rev. Porro  No    25-year Limited
  Minolta Compact 8x23              $132   Rev. Porro  No    25-year Limited
  Nikon Travelite III 9x25          $156   Rev. Porro  No    25-year Limited
  Pentax UCF 8x24                   $160   Rev. Porro  No    Limited Lifetime
  Redfield 8x24                     $210   Roof        No    Limited Lifetime
  Swift Micron 8x25 CF              $120   Rev. Porro  No    Limited Lifetime
  Zeiss Design Selection 8x20 BT    $530   Roof        No    25-year

* Top rated

                                                                        Play of
                                 Interpupil       Good for    Weight     Focus
    Model                         Distance       Eyeglasses? (ounces)  (degrees)

Over $800:

* Bausch & Lomb Elite 10x42   2-3/16" - 2-7/8"       2         28.1       400
* Bausch & Lomb Elite 8x42    2-3/16" - 2-7/8"       1         29.1       400
* Bausch & Lomb Elite 7x36    2-3/16" - 2-7/8"       1         25.4       400
* Leica Ultra 10x42 BA        2-3/16" - 2-7/8"       2         32.0       330
* Leica Ultra 8x42 BA         2-3/16" - 2-7/8"       2         32.0       330
  Nikon Classic Eagle 8x40    2-1/8" - 2-13/16"      2         28.2       190
* Zeiss Dialyt 10x40 B/GAT    2-3/16" - 3"           2         26.4       330
* Zeiss Dialyt 7x42 B/GAT     2-1/4" - 2-15/16"      1         28.2       450

$500-$800:

  aus Jena Luxus 10x40        2-3/16" - 2-7/8"       3         24.6       270
  Bausch 7 Lomb Custom 10x40  2-1/4" - 2-13/16"      2         30.9       460
  Nikon Execulite 9x30        2-3/16" - 2-7/8"       4         16.7       630
* Nikon E CF HP 8x30          1-7/8"  - 2-7/8"       2         20.0       330
* Optolyth Touring 10x40      2-1/8" - 3"            2         24.0       410
  Swift Audubon 7x35          2-1/4" - 3-1/16"       2         21.0       460

$200-$500:

  Celestron Ultima 10x42      2" - 2-7/8"            2         19.7       360
  Celestron Ultima 8x32       2" - 3"                2         17.4       370
  Minolta Weathermatic 7x42   2-1/4" - 2-7/8"        1         29.1       270
  Optolyth Alpin 10x40        2" - 2-3/4"            4         18.2       690
  Optolyth Alpin 7x42         2" - 2-3/4"            2         18.1       690
  Optolyth Alpin 8x30         2" - 2-3/4"            4         14.9       690
  Pentax DCF 8x42             2-1/4" - 2-7/8"        2         31.0       360
  Pentax PCF 7x50             2-3/16" - 2-3/4"       2         31.8       590
  Pentax PCF 7x35             2-3/16" - 2-3/4"       3         24.3       560
  Redfield WP 10x50           2-3/8" - 3-1/16"       3         28.6       170
  Redfield WP 7x35            2-5/16" - 3-1/16"      2         20.5       170
  Swift Audubon 8.5x44        2-1/8" - 3-1/4"        2         28.9       460
* Swift Ultra Lite 8x42 ZWCF  2" - 2-15/16"          2         21.0       370
  Swift Egret 10x42 HCF       2-1/4" - 2-13/16"      4         18.3       320

Under $200:

* Bushnell Birder 7x35        2-3/16" - 2-7/8"       3         18.8       460
  Minolta Standard 7x35       2-3/16" - 2-13/16"     3         26.8       270

Compacts:

* B&L Custom Compact 7x26     2-1/4" - 3-1/8"        2         11.5       370
  Leica 10x25 BCA             1-1/4" -  3-1/4"       4          8.8       740
  Leica 8x20 BCA              1-1/4" -  3-1/4"       4          8.1       740
  Minolta Pocket 7x21         1-3/8" -  2-3/4"       4          9.7       350
  Minolta Compact 8x23        2-1/4" - 2-7/8"        4          8.8       340
  Nikon Travelite III 9x25    2-1/8" - 2-7/8"        4          9.4       350
  Pentax UCF 8x24             2-3/16" -  2-15/16"    4          9.9       590
  Redfield 8x24               1-3/8" - 3-1/16"       4          9.6       270
  Swift Micron 8x25 CF        2-1/4" -  2-13/16"     4         10.1       740
  Zeiss Design Selection 8x20 1-1/4" -  2-7/8"       4          6.4       350

* Top rated        Numeric Ratings: 1 to 5, 1 is best


                                                Optical     Min.   Field of
                                 Focus  Bright-  Perfor-   Focus    View at
         Model                    Feel   ness     mance    Dist.      230'   Fog
Over $800:

* Bausch & Lomb Elite 10x42        1       2       1        11'      23.8'    N
* Bausch & Lomb Elite 8x42         1       1       1      10.5'      27.5'    N
* Bausch & Lomb Elite 7x36         1       1       1         5'        30'    N
* Leica Ultra 10x42 BA             1       2       1        14'        20'    N
* Leica Ultra 8x42 BA              1       1       1        12'        20'    N
  Nikon Classic Eagle 8x40 DFC     1       3       2      14.5'      27.5'    N

* Zeiss Dialyt 10x40 B/GAT         2       3       1        15'        20'    N
* Zeiss Dialyt 7x42 B/GAT          1       1       1       9.5'        30'    N

$500-$800:

  aus Jena Luxus 10x40             1       3       2        18'        20'    N
  Bausch 7 Lomb Custom 10x40       1       3       2        12'        20'    Y
  Nikon Execulite 9x30             1       5       2        11'      22.5'    Y
* Nikon E CF HP 8x30               1       2       1        11'      32.5'    Y
* Optolyth Touring 10x40           2       3       1        16'      27.5'    Y
  Swift Audubon 7x35               2       2       2        10'        20'    N

$200-$500:

  Celestron Ultima 10x42           1       2       2        15'      23.8'    Y
  Celestron Ultima 8x32            2       4       3        12'        30'    Y
  Minolta Weathermatic 7x42        1       3       3        12'        25'    N
  Optolyth Alpin 10x40             1       3       3        14'        25'    Y
  Optolyth Alpin 7x42              1       5       3        27'        25'    N
  Optolyth Alpin 8x30              1       5       3        13'      32.5'    Y
  Pentax DCF 8x42                  1       5       3        24'      27.5'    N
  Pentax PCF 7x50                  2       1       3        15'      22.5'    Y
  Pentax PCF 7x35                  2       3       4         7'        25'    Y
  Redfield WP 10x50                2       4       3      24.5'      22.5'    N
  Redfield WP 7x35                 2       4       3      10.5'        25'    N
  Swift Audubon 8.5x44             1       3       2      10.5'     31.25'    Y
* Swift Ultra Lite 8x42 ZWCF       1       2       2        16'        20'    N
  Swift Egret 10x42 HCF            1       5       3        14'        25'    N

Under $200:

* Bushnell Birder 7x35             2       2       3        13'      22.5'    Y
  Minolta Standard 7x35            2       3       3      12.5'        32'    Y

Compacts:

* Bausch & Lomb Custom Comp. 7x26  1       1       2         6'      27.5'    Y
  Leica 10x25 BCA                  3       4       3        16'        20'    N
  Leica 8x20 BCA                   3       4       4         8'      26.3'    N
  Minolta Pocket 7x21              2       4       5         6'      26.3'    N
  Minolta Compact 8x23             2       3       5        21'        25'    Y
  Nikon Travelite III 9x25         2       2       3        12'        20'    Y
  Pentax UCF 8x24                  3       2       5       8.5'        25'    N
  Redfield 8x24                    2       4       5      14.5'      28.5'    N
  Swift Micron 8x25 CF             2       3       4         6'        20'    Y
  Zeiss Design Selection 8x20 BT   2       3       4         8'        25'    Y

* Top rated        Numeric Ratings: 1 to 5, 1 is best

4.3. British Birds (Owner Survey, Binoculars and Scopes, July 1991)
==================================================================

From _British Birds_, 84:7, July 1991, pp. 267-282 comes this reader survey.
Many thanks to Adrian Wander for typing this in.
 
Most Popular Binoculars
-----------------------
1  Zeiss West Dialyt 10*40       28.4%
2  Zeiss West 7*42                8.8%
3  Leitz Trinovid 10*40           6.0%    Other well known makes placed:
4  Swift Audubon 8.5*44           5.5% 
5  Optolyth Alpin 10*40           4.9%    11 Bausch and Lomb Elites 10*42  1.7%
6  Optolyth Alpin 10*50           4.2%    12 Bausch and Lomb Elites 8*42   1.4%
7  Zeiss Jena Jenoptem 10*50      3.7%    13 Leica 10*42                   1.3%
8  Leitz Trinovid 8*40            2.8%    16 Leitz Trinovid 7*42           1.2%
9  Swarovski/Habicht Diana 10*40  2.4%    17 Zeiss West Dialyt 8*30        1.1%
10 Zeiss Jena Notarem 10*40       1.9%
 
Most Highly Rated Binoculars
----------------------------
(6=excellent 5=very good 4=good 3=satisfactory 2=poor 1=very poor)
 
   Make                          No Owners  Average Rating
1  Bausch and Lomb Elite 8*42       12          6.00
2  Leica 10*42                      11          6.00
3  Optolyth 9*63                     5          6.00
4  Zeiss West 7*42                  72          5.94
5  Leitz Trinovid 8*40              23          5.87
6  Bausch and Lomb Elite 10*42      14          5.86
7  Leitz Trinovid 7*42              10          5.80
8  Leitz Trinovid 10*40             50          5.78
9  Zeiss West Dialyt 10*40         241          5.76
10 Leica 8*42                        4          5.75
 
(13 Zeiss West Dialyt 8*30           9          5.56
 14 Swarovski/Habicht Diana 10*40   20          5.50
 20 Zeiss West 10*50                 4          5.25
 21 Swift Audubon 8.5*44            46          5.20
 23 Optolyth Alpin 8*40             11          5.09)
 
Most Satisfactory Binoculars (number of owners who would buy the same again)
----------------------------------------------------------------------------
 
1  Leica 8*42                         4/4        100.0%
2  Bausch and Lomb Elite 8*42        11/12        91.7
3  Zeiss West 7*42                   61/73        83.6
4  Leica 10*42                        9/11        81.8
5  Bausch and Lomb Elite 10*42       11/14        78.6
6  Optolyth Alpin 8*30                2/3         66.7
7  Zeiss West Dialyt 10*40          154/236       65.3
8  Nikon 8*30                         4/7         57.1
9= Swarovoski/Habicht Diana 10*40    10/20        50.0
9= Opticron Classic 10*42             3/6         50.0
 
(14 Swift Audubon 8.5*44             15/46        32.6
 15 Optolyth Alpin 10*40             13/41        31.7
 16 Leitz Trinovid 7*42               3/10        30.0
 20 Optolyth Alpin 10*50              9/35        25.7
 21 Leitz Trinovid 10*40             12/50        24.0
 22 Leitz Trinovid 8*40               5/23        21.7
 24 Optolyth Alpin 8*40               2/11        18.2
 26 Zeiss West Dialyt 8*30            1/9         11.1)
 
Top Binoculars for the Future (intended future purchases)
---------------------------------------------------------
 
1  Zeiss West Dialyt 10*40        28.5%
2  Zeiss West 7*42                13.8%
3  Leica 10*42                     8.8%    Other well known makes placed:
4  Leica 8*42                      4.2%
5= Leitz Trinovid 10*40            2.8%    11 Optolyth Alpin 10*50     1.8%
5= Swift Audubon 8.5*44            2.8%    14 Leitz Trinovid 8*40      0.8%
7= Bausch and Lomb Elites 10*42    2.6%    16 Swift Audubon 7*35       0.7%
7= Bausch and Lomb Elites 8*42     2.6%    18 Zeiss West Dialyt 8*30   0.5%
9  Optolyth Alpin 10*40            2.3%
10 Swarovski/Habicht Diana 10*40   1.9%
 
Most Popular Scopes
-------------------
 
1  Kowa TSN1/2 *77                              16.2%
2  Bushnell Spacemaster *60                     12.2%
3  Kowa TSN3/4 *77                               7.7%
4  Optolyth TBS/G80                              7.5%
5  Optolyth 30*75                                6.9%
6  Nikon Fieldscope EDII *60                     5.8%
7  Kowa TS1/2 *60                                4.7%
8  Nikon Fieldscope ED *60                       4.5%
9  Opticron High Resolution *60                  3.6%
10 Bushnell/Bausch and Lomb Discoverer 15-60*60  3.2%
(11  Optolyth 30*80                              2.1%
 12= Questar Mirrorlens                          1.9%)
 
Most Highly Rated Scopes
------------------------
(6=excellent 5=very good 4=good 3=satisfactory 2=poor 1=very poor)
 
   Make                          No Owners  Average Rating
1  Questar Mirrorlens              15            6.00
2  Kowa TSN3/4 *77                 59            5.93
3  Nikon Fieldscope EDII           40            5.90
4  Nikon Fieldscope EDI            36            5.89
5  Nikon Fieldscope I and II        7            5.71
6  Optolyth TBS/G80                62            5.56
7  Kowa TSN1/2 *77                125            5.46
8  Optolyth 30*80                  16            5.38
9  Alderscope 25*80                 3            5.33
9= Swarovski/Habicht 30*75          3            5.33
(11 Optolyth 30*75                 52            5.17
 13=Kowa TSN1/2                    36            5.00
 15 Bushnell Spacemaster *60       94            4.86
 18 Bushnell/Bausch and Lomb
    Discoverer 15-60*60            25            4.52)
 
Most Satisfactory Scopes (number of owners who would buy the same again)
------------------------------------------------------------------------
 
1   Kowa TSN3/4 *77                47/59            79.7%
2   Nikon Fieldscope EDI and II    58/76            76.3%
3   Questar Mirrorlens             11/15            73.3%
4   Optolyth TBS/G80               31/62            50.0%
5   Nikon Fieldscope I and II *60   3/7             42.9%
6   Optolyth 30*80                  6/16            37.5%
7   Adlerscope 25*80                1/3             33.3%
8   Kowa TSN1/2 *77                37/125           29.6%
9   Optolyth 30*75                 13/53            24.5%
10  Bushnell Spacemaster *60       19/94            20.2%
(14 Kowa TSN1/2 *60                  4/36            11.1%
 16 Bushnell/Bausch and Lomb                            %
    Discoverer 15-60*60             1/25             4.0%)
 
Top Telescopes for the Future (intended future purchases)
---------------------------------------------------------
 
1  Kowa TSN3/4 *77                     20.5%
2  Nikon Fieldscope EDI and II         19.3%
3  Optolyth TBS/G80                     9.2%
4  Kowa TSN1/2 *77                      8.8%
5  Questar Mirrorlens                   3.5%
6  Bushnell Spacemaster *60             3.2%
7  Kowa TS601/602 *60                   2.7%
8  Optolyth 30*75                       2.3%
9  Optolyth 30*80                       1.6%
10 Nikon Fieldscope I and II            0.9%

4.4 Living Bird Quarterly (Scopes -- Autumn 1990)
=================================================

The following is a summary of the excellent article "Scanning for Optics II"
from _The Living Bird Quarterly_, Autumn 1990, pp 12-15.  Authors are
Bonney and Forbes-Robertson.  Highest rating is 1, lowest is 5.

1. Kowa TSN-4 and TSN-2: winners; zoom clear; if you have the money, buy the 4.

1. Nikon ED II Fieldscope: excellent; smaller, lighter than Kowas; zoom clear;
	focus ring awkward; depth of field shallow.

2. Optolyth TBG80: very good; image not sharp at high power; smaller field-
	of-view than Kowa; shallower depth of field.

2. Mirador SSD: can't match TSN-2; good clarity, but dark.

2. Bausch & Lomb Elite 22x: not as clear as some; outstanding for eyeglasses.

3. Questar Field Model: phenomenal image; 6x, 50x, and 80x impractical for
	most birding; heavy. 

3. Celestron C-90: heavy; bright, clear image; small field-of-view; 33x only;
   focus awkward.

   [additional owner comments: also comes with 25mm orthoscopic eyepiece
   that yields closer to 40x; slow motion head available; Barlow lens
   accessory doubles power while retaining eye relief for glasses wearers;
   comes in stout camera case.]

3. Zeiss 30x60 B/GA: image bright, but mediocre; not up to Zeiss reputation.

3. Bausch & Lomb Elite 15-45x: only good, unlike 22x; image worse as zoom
	increases.

3. Bushnell Spacemaster: best inexpensive scope; use 22x, zoom not good.

4. Optolyth 22-60x 70mm: image excellent; field-of-view tiny; shakes in wind.

4. Swarovski 25-40x 75 NZ and 30-75x 75 NZ: didn't care for either.

4. Celestron C-60: disappointment; dark and moderately clear.

5. Meade Pathfinder II and Swift Searcher: bad image.


5. Sources for Optical Equipment
================================

If you belong to a buying service, try that first.  One example:  B & L
Elite 22 x 60 scope, list: $750, best mailorder: $400, buying service: $200.
Several credit cards offer buying services. Another buying service that
is somewhat widespread throughout the US is United Consumers Club.

Also, check the New York City mail order sources that advertise in the
back of Popular/Modern Photography.  Be aware, however, that these places
often carry what are known as foreign market or grey market goods.  These
are products produced for sale in countries other than the US. Sometimes
these products are manufactured to different specifications; sometimes
they are identical. In any case, you will not have any US warranty on
the goods and may not get any frills either (carrying case, strap, etc.).
The prices are appealing, but caveat emptor.

Before buying any mail order optics, you should read the Mail Order Survey
that Douglas Blondin (blondin@blanca.att.com) maintains.  He posts this
survey, listing experience with most of national photographic and optics
stores, about once a month on rec.photo and rec.video.
 
The sci.astro newsgroup is a good place to ask about optics suppliers.

ABA Sales (Colorado Springs, CO) 800-634-7736, 719-578-0607 -- This is the
sales organization of the American Birding Association.  They do a great
job of stocking items for birders.  Their optics selection is good and
their prices are becoming more competitive.  You cannot ask for better
service.  ABA members get discounts.  The catalog has a lot of useful
comparisons of optical equipment.

Birding (Amsterdam, NY) 518-842-0863 -- APPARENTLY OUT OF BUSINESS 

B & H (New York, NY) 800-221-5662, 212-807-7474 -- "I have bought tons
from B&H...highly approved of by the pros who haunt rec.photo.... They're
honest, don't bait and switch, add garbage pieces, tell you how much
everything including shipping will cost, when you'll get it, etc....
Their prices run slightly higher than some other NY mail-order houses but
honesty and fairness make it worthwhile."

Christopher's Ltd (Norman OK) 800-356-6603 -- "primarily an
astronomy-oriented optical dealer, but good selection, decent prices, and
top-notch advice on many spotting scope options."

Eagle 608-271-4751 -- "really helpful"

Executive Photo, (New York, NY) 800-223-7323, 212-947-5290 -- avoid, based
on many negative comments

National Camera (MN) 800-624-8107, 612-546-6831

Orion (Santa Cruz, CA) 800-447-1001 -- large selection of equipment of interest
to birders.

Yoder 216-893-2464

6. Useful Reference Material
============================

_Better View Desired_, Whole Life Systems, P.O. Box 162, Rehoboth, NM 87322.
Subscriptions are $15 per year (4 issues). All back issues are available for
$4 per issue: August 1992, Mid-sized Binoculars; November 1992, High-powered
Binoculars; February 1993, Refractor Spotting Scopes; April 1993, Budget
Binoculars; August 1993, Full-Sized Birding Binoculars.

Culver and Gerhart, "Binocular Quest", _Living Bird_, Autumn 1992.

"Binocular and Scope User Survey", _British Birds_, 84:7, July 1991,
pp. 267-282.

Bonney and Forbes-Robertson, "Scanning for Optics II", _The Living Bird
Quarterly_, Autumn 1990, pp 12-15.

_Birding_ (photo issue), February, 1989.  See also the "Tools of the Trade"
column in most issues.

7. Contributors
===============

Thanks to the following individuals who have helped with this FAQ:

Bob Atkins     Richard Ditch  Frank Kolwicz  Kevin McGowan  Brian Townes
Don Baccus     Dave Eshbaugh  Tony Lang      Peter Nurkse   Tim Walker
Mike Burger    L Gorbet       Laurie Larson  David Rintoul  Adrian Wander
Byron Butler   David Graham   Tom Lathrop    Daan Sandee    Steve Willner
Dalcio Dacol   Sid Johnson    Harry Lehto    Rocky Rothrock
-- 
Ed Matthews                                      Internet: edm@verdix.com
Manager of CASE Development                         Voice: (703) 318-5832
Verdix Corporation Headquarters                       Fax: (703) 318-9304
Herndon, Virginia USA
-- 
Ed Matthews                                      Internet: edm@verdix.com
Manager of CASE Development                         Voice: (703) 318-5832
Verdix Corporation Headquarters                       Fax: (703) 318-9304
Herndon, Virginia USA

