From: edm@verdix.com (Ed Matthews)
Subject: January Optics FAQ
Organization: Verdix Corp
Date: Wed, 27 Jan 1993 19:22:34 GMT

        Frequently Asked Questions about Optics for Birding

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
=========================================

+ Clarifications
+ New Info about Aging vs. Pupil Dilation
+ More on Buying Services
+ Info on Foreign Market Goods
+ Close Focus Info

Help Me
=======

1. Can you tell me if Bogen and Manfrotto tripod model numbers correspond?
2. Can you give me information on where to buy optics?

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?
3. Tripods
4. Ratings
4.1 Scopes
4.2 Binoculars
4.3 User Surveys
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.

Users 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 OpTech 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 a 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.

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

In the US, we calculate field-of-view at a distance of 1000 yards.
Typical field-of-view values at 1000 yards range between 5 and 8.5
degrees, which correspond to a field-of-view 263 feet to 446 feet wide.

The wider the field-of-view, the better the instrument for picking up
motion in the distance.  The narrower the field-of-view, the better the
instrument is for closeups.  Less expensive instruments with a large
field-of-view generally have considerable distortion at the edges.

In many cases, the actual field-of-view may be markedly different
than what the manufacturer indicates it is.

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.

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 is not generally possible.  Requires fast film and bright sun.

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.

3. Tripods
==========

Users 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.  Both are described below.  Gitzo also makes
fine tripods which are popular in Europe.

Bogen (Manfrotto outside the United States)

[note: it is not clear whether Bogen model numbers correspond to Manfrotto]

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 the scope very steady in the wind.  The quick
release plate for the micro-fluid head is nice, especially for
switching between scope and camera.  The leg levers take some strength
to operate.  Leg can open noisily if not careful.  Good for tall
birders.  Replacement parts are readily available.  Users 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.]  Users
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.
Users seem to be universally happy with this tripod.

4. Ratings

4.1 Scopes

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.

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.

4.2 Binoculars
==============

[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. User Surveys
=================

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%


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.).
But the prices are appealing.  Caveat emptor.

Birding (518) 664-2011  **** CONFLICTS w/ below *******

Birding (Amsterdam, NY) 518-842-0863 - no toll free number, but comments
 (above) about selection, price and advice at Christopher's apply here
 as well.

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, see any issue of Popular/Modern Photography
National Camera (800) 624-8107
Orion, Santa Cruz CA, (800) 447-1001
Yoder (216) 893-2464

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

"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.

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

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

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

Mike Burger
Byron Butler
Dalcio Dacol
Sid Johnson
Tony Lang
Kevin McGowan
Peter Nurkse
David Rintoul
Rocky Rothrock
Daan Sandee
Brian Townes
Tim Walker
Adrian Wander
Steve Willner
-- 

Ed Matthews                                                edm@verdix.com
Manager, APSE Development
Verdix Corporation Headquarters                            (703) 318-5800
Newsgroups: rec.birds,rec.pets.birds