Small Binocular Reports
A Dozen 8s
3-8-08
Ed Zarenski
This is one in a series of "Small
Binocular" reports that
will detail and summarize all my findings from eight months of tests
and
measures on over 30 binoculars. Sizes ranged from 7x50, 8x32 and 8x40
up to 8x42 and 10x42 roofs, 10x50,
10x60 and 12x50s. These are all
sizes that could be hand-held and used for either terrestrial use or
astronomy. Sprinkled throughout
the list of binoculars are several benchmark models that give a good
indication
what all the others should hope to achieve. Here are the test results
for a dozen 8 power binoculars, including
8x40s, 8x42s, several roof prism 8x42s, and a few larger or smaller
than that nominal size
range. Be sure to refer to the
other reports, especially the Small Binocular Score, the report showing
the
summary scores for 16 different measured aspects for all 34 binoculars
tested.
Clockwise from front left: Garrett Apo 8x42 roof, Celestron Regal 8x42
roof, Fujinon
BFL 8x42, Nikon Action Extreme 8x40, Nikon Action 8x40, Pentax PCF WP
II 8x40,
Bushnell Legend 8x42 roof, Oberwerk Mariner 8x40, Nikon SE 8x32.
Center: Garrett Classic 8x45.
For the most part this portion of the study is based on 8x40
and 8x42 binoculars. However, a
few other 8s that fit best here were included, such as 8x56 and an
8x45. Again you will see even though those
are nominally larger, they fit fairly close in with this size range.
Also, the 8xroofs were included here
even though they were reviewed with the roofs. The fact that they are
roofs does not preclude them from being
included in this appropriate 8x size comparison. The Nikon SE 8x32 is
used as a benchmark here. In some cases you will see this little
32mm binocular performs as well or better than some of the nominal
40/42mm
binoculars tested.
Binocular
Basics
|
actu
|
Net
|
actu
|
use
|
range
|
oz.
|
gm
|
spec
|
prism
|
$$$
|
Small
Binoculars
|
Mag
|
Aper
|
FOV
|
ER
|
IPD
|
wgt
|
wft
|
coat
|
coat
|
cost
|
Oberwerk
8x56
|
8.1
|
48
|
5.7
|
21
|
59-72
|
36
|
1022
|
fmc
|
fmc
|
99
|
Garrett
Classic 8x45
|
8.1
|
38
|
7.3
|
18
|
59-74
|
29
|
823
|
fmc
|
fmc
|
100
|
Celestron
Regal 8x42 rp
|
8.1
|
42
|
6.3
|
17
|
58-74
|
25
|
709
|
fmc
|
fmc/p
|
169
|
Bushnell
Legend 8x42 rp
|
8.2
|
41
|
6.5
|
17
|
58-74
|
25
|
709
|
fmc
|
fmc/p
|
249
|
Garrett
DCF 8x42 Apo rp
|
8
|
41
|
6.7
|
19
|
57-71
|
23
|
653
|
fmc
|
fmc/p
|
200
|
Swift
Ultralite 8x42
|
8
|
41
|
6.5
|
19
|
51-76
|
21
|
596
|
fmc
|
fmc
|
169
|
Fujinon
BFL 8x42
|
8.0
|
40
|
6.5
|
11
|
57-73
|
24
|
681
|
fmc
|
fmc
|
189
|
Pentax
PCF WP II 8x40
|
8.0
|
39
|
6.3
|
13
|
57-74
|
31
|
880
|
fmc
|
fmc
|
149
|
Nikon
Action Ex 8x40
|
7.9
|
39
|
8.1
|
14
|
56-73
|
30
|
851
|
mc
|
MgF
|
124
|
Nikon
Action VII 8x40
|
7.9
|
38
|
8.15
|
11
|
56-73
|
26
|
738
|
mc
|
MgF
|
65
|
Oberwerk
Mariner 8x40
|
8.0
|
32
|
8.0
|
16
|
62-73
|
33
|
936
|
fmc
|
fmc
|
139
|
Nikon
SE 8x32
|
8
|
32
|
7.6
|
14
|
53-73
|
22
|
624
|
fmc
|
fmc
|
550
|
Values are measured actual magnification x effective
aperture, True field of view, usable eye relief, interpupilary range,
weight, lens
coat/prism coat and retail purchase price. The Nikon SE 8x32 is
included as a benchmark.
More Basics
The Oberwerk 8x56 is heaviest at 36oz. (1020g.), and the
small Oberwerk Mariner 8x40 is not far behind at 33oz. (930g.), both
these
about the weight of a normal 10x50 and even heavier than a few 10x50s
which go
as low as 30oz. (850g.). Towards
the heavy end, about the same weight as the lightest 10x50s, are the
Pentax PCF
WP II and the Nikon Action Ex. Quite a few of these weigh in close to
25oz. (700g.). At the very lighest end of the spectrum
are the Fujinon BFL, the Garrett Apo roof and the Swift Ultralite.
The
Fujinon BFL weighs only 24 oz. (680gm.) and is like a little baby
binocular in comparison to the monster sized FMT-SX 10x70. Even the
49oz. (1400gm) Fujinon FMT-SX 10x50, which is much smaller than the
FMT-SX 10x70, still has considerably more heft than this little 8x42.
The 8x42 BFL, not necessarily the lightest or smallest, is one of the
most comfortable small binoculars to carry around.
The Fujinon BFL is just a bit smaller than the Nikon SE
10x42, shown in middle. The Nikon
SE 8x32, left, is a bit too small for my hands.
I like the one-piece style cover that fits snuggly over both
eyepieces. Nikons, the Regal LX as
well as Bushnell, Swift and the Oberwerk Mariner all have the same
style
one-piece eyelens cover.
I don't like objective push-in caps. The Regal, the Nikons,
the Mariner and the Classic all have push in objective caps. The Pentax
the Swift and the Fujinon
all have push over caps, but none are captive and all are loose. The
Oberwerk 8x56 has good fitting push
over caps. The Bushnell roof has captive objective caps push over.
You don't get a lot of room for an L bracket between the barrels of a
roof
prism binocular. The narrow bracket that came with my Oberwerk Ultra
15x70 is
only 10mm wide and works perfectly. None of the roofs can be used on
the Far
Sight Binocular Mounting bracket. No
other standard L bracket I own would work for the roofs, although there
are
other narrow L brackets available that would work. However, I must say,
difficulty mounting small roof prism
binoculars should not be considered a problem. Very few people will be
mounting small 8x42 roofs. I do have a velcro strap style adapter
from Eagle Optics that works well with all the roofs and the lighter
porros. All of the 8x porros are
easy to mount on any type bracket.
The Pentax porro eyeguard twists and stops at both an intermediate
position and
full out. It has no unwanted
loose movement. The GO 8x45, the
Fujinon BFL, the Nikon Action, the Swift Ultralite and the Oberwerk
8x56 all
have folding rubber eyecups. The
Oberwerk Mariner has a hard rubber eyeguard that twists out with
friction that holds
it in place at any position. The
Regal has a push/pull eyeguard with one positive click midway. It did
not move
from the midway or full out click positions. The Bushnell Legend porro
twists out
to three very positive detente settings. The Nikon Action Extreme also
has a hard
rubber eyeguard that twist out. Similar to the Legend, it has three
positive positions with no
slip. The Garrett Apo roof has a
twist out eyeguard, but it seems it will not stay put at any
intermediate
position, so it must be used either all the way in or all the way out.
The Regal is waterproof/fogproof, O-ring sealed and nitrogen
purged. But, if I'm not mistaken, so are the Bushnell Legend and the
Garrett
Apo roofs. Of the porros, the Oberwerk 8x56, the Swift Ultralite and
the Nikon
Action are NOT waterproof.
The Swift Ultralite, Pentax and Nikon AE have very little pincushion.
The Oberwerk Mariner 8x40 and the
Garrett Classic 8x45 have the most pincushion. The Garrett roof has the
least pincushion of the roofs. None of the others have severe
pincushion. Keep in mind pincushion has absolutely
no affect on astronomical observing. However, it does have considerable
affect
for terrestrial users, and all of these are considered good size
cross-over
binoculars. A small amount of pincushion is desirable as it helps
eliminate the
rolling ball effect for terrestrial use. So pincushion is a meaningful
criteria that affects terrestrial users
differently than astro users.
Eye Relief – Diopter - IPD
With the exception of the Fujinon BFL (speced er=15mm) and
the Nikon Action (speced er=12mm) the specified eye relief on all of
these is quite
substantial, between 17-24mm. The
Bushnell roof (17mm), the Garrett roof, the Swift Ultralite, the
Oberwerk
Mariner and the Garrett Classic come very close to specified and all
have long usable
eye relief. The Pentax PCF WP II is
specified at 20mm, it actually has only usable eyerelief of 13mm.
Several of these binocular have eye lenses and the metal rim
surrounding the eye lens positioned too close to the top of the
retracted eye
guard. Garrett Classic, Garrett
roof Swift Ultralite And Nikon Action all have only only 2mm clearance
to the eye lenses when the eyecups are
turned fully down. This is insufficient
distance to prevent contact with eye glasses, requiring that the eyecup
be
twisted out somewhat so eyeglasses don't hit the binocular eye lens.
The Swift
metal rim is covered with the rubber eyecups, so the metal on that one
is not a
proble. On the others both the
metal rim at the edges of the eye lens and on all of them the fact that
the eye
lens is only 2mm deep means you need to be careful when using these
with
eyeglasses.
Eye
Relief
|
spec
|
dist
|
rcss
|
usable
|
usable
|
Small
Binoculars
|
ER
|
exit
|
lens
|
ER
|
w/cup
|
Oberwerk
8x56
|
24
|
24
|
3
|
21
|
9
|
Garrett
Classic 8x45
|
19
|
20
|
2
|
18
|
4
|
Celestron
Regal 8x42 rp
|
20
|
21
|
4
|
17
|
7
|
Bushnell
Legend 8x42 rp
|
18
|
21
|
4
|
17
|
9
|
Garrett
DCF 8x42 Apo rp
|
20
|
21
|
2
|
19
|
9
|
Swift
Ultralite 8x42
|
20
|
21
|
2
|
19
|
7
|
Fujinon
BFL 8x42
|
15
|
17
|
6
|
11
|
5
|
Pentax
PCF WP II 8x40
|
20
|
18
|
5
|
13
|
3
|
Nikon
Action Extreme 8x40
|
17
|
18
|
4
|
14
|
4
|
Nikon
Action VII 8x40
|
12
|
13
|
2
|
11
|
4
|
Oberwerk
Mariner 8x40
|
18
|
19
|
3
|
16
|
9
|
Nikon
SE 8x32
|
17
|
19
|
5
|
14
|
5
|
With the curvature of my eyeglass lenses, at least 3mm depth
is needed below the eyeguard to keep eyeglass lenses from hitting and
scratching the binocular eye lens, or just as bad, scratching my
eyeglass
lenses. It would cost me more to
replace my eyeglass lenses than it would to replace these binoculars.
The
Celestron Regal LX has 4mm depth. The Bushnell Legend has 4mm. All of
these others have the rubber
eyeguard raised just enough above the metal eyepiece edge rim to
prevent the
metal from touching my eyeglasses.
The Fujinon BFL right diopter is the rotating eyepiece
style, as is the Nikon Action, the Swift and the Garrett Classic. The
BFL has clickstops. The
Nikon AE, Pentax, and Oberwerk Mariner have a slide bar under the right
eyecup.
The Garrett roof has a right diopter ring that seems
designed to prevent it from accidentally being moved. It is narrow, low
profile, under the right eyecup, difficult
to grip and tight, that it’s difficult
to turn them while looking through the
binocular. The Bushnell right diopter ring is prominently raised and is
very
easy to use. The Celestron Regal
is unique in that the right eyecup is push/pull for eye relief and is
twist for
diopter. The first 8xRegal I
received broke within 2 days. The
replacement works, but is the coarsest movement of any right diopter on
any of
these binoculars.
Most of these are very similar in IPD range, ranging from 56-73mm to
58-74mm. The Swift Ultralite accommodates from
51mm-76mm, the widest range of all. However, a few have a wide minimum
IPD. While 58mm is close enough for most people, some adults will
need 57mm and many children with close-set eyes need even less to see
with both
eyes. The Oberwerk 8x56 and the
Garrett Classic 8x45 have a minimum IPD of 59mm, and the Oberwerk
Mariner
minimum is 62mm, these sizes not suitable for many children.
Close Focus
Most of the porros have a close focus from 13ft.to 15ft. The roofs all
focus to within
5-7ft. The Pentax and the Nikon
Action get as close as 11ft. the
Oberwerk 8x50 can get no closer than 50ft. Using 20ft as the focus
point, those that can focus to 20ft
have between 80-87% of the fov overlapped for binocular vision. The
roofs, which all focus to much
closer than 20ft, have closer to 90% of the fov in binocular vision at
20ft.
What you really get with these binoculars when it comes to
close focus (assuming at 10ft) is a "binocular vision" field of view
about 10 inches wide. Both the
Bushnell Legend (6.5° fov) and the 10xRegal
(6.0°fov) show nearly identical
results. At a distance of 10 feet
they can see 31-32cm with only 25 cm of that field overlapped, so for
binocular
vision they see 10 inches out of just over 12 inches. In these same
binoculars, when viewing at 100 feet (30m) the
barrel overlap is off by less than 5% of the fov and you get a 10 foot
wide
view with binocular vision while only 6-8 inches is not overlapped.
Internal Focus
These three roofs are internal focus. I can observe the
internal sliding mechanism sleeve in front of the prism. If a binocular
is
internal focus, and therefore, the eyepieces do not move, then an
internal lens
is moving to achieve focus and therefore focal length and resultant
light cone gets
modified slightly so the focal point will hit the unmoving eyepiece to
change
from close focus to infinity. That
probably means all these roofs are changing magnification as you move
towards
closer focus. I did a quick check
of the 8xRegal at a focus distance of about 10ft and found
magnification close
to 8.5x. That's a 4-5% increase in
magnification. The Bushnell shows
about 8.6x, an increase of 5%.
Close
Focus
|
****
|
close
|
dial
|
dial
|
Small
Binoculars
|
focus
|
focus
|
3-30
|
30-100
|
Oberwerk
8x56
|
CF
|
50
|
na
|
135
|
Garrett
Classic 8x45
|
CF
|
15
|
270
|
120
|
Celestron
Regal 8x42 rp
|
Cf in
|
6
|
300
|
30
|
Bushnell
Legend 8x42 rp
|
Cf in
|
7
|
180
|
30
|
Garrett
DCF 8x42 Apo rp
|
Cf in
|
5
|
270
|
60
|
Swift
Ultralite 8x42
|
CF
|
14
|
270
|
45
|
Fujinon
BFL 8x42
|
CF
|
14
|
145
|
45
|
Pentax PCF
WP II 8x40
|
CF
|
11
|
300
|
60
|
Nikon
Action Extreme 8x40
|
CF
|
13
|
330
|
30
|
Nikon
Action VII 8x40
|
CF
|
11
|
285
|
45
|
Oberwerk
Mariner 8x40
|
CF
|
15
|
108
|
54
|
Nikon
SE 8x32
|
CF
|
9
|
300
|
90
|
Slow or Fast Focus
As I've done with all the binoculars in the Small Binocular
studies, I've attempted to class them as
slow or fast focus. But what I found was, fast or slow is
not necessarily consistent across all distance ranges. So, I measured
the dial degrees turn
needed to go from 3 meters to 30 meters (10feet to 100feet) and then
measured
the degrees turn to go from 30m to 100m (100ft to 300ft). For instance
both the Bushnell roof and
the Regal roof take only 30° of focus dial turn to
focus from 30M to 100M.
Typical fast focus binoculars have a total dial turn
20-deg to 60-deg for the 30M-100M
range. However, for the range from 3M to 30M, the Bushnell can cove
that
distance with only 180-deg of focus dial turn, while
the Regal needs 300-deg of
turn. The Regal would not be
considered fast focus in the short range.
Most of these binoculars, in the close range from 30m to 3m
(100ft to 10ft), take about 300-deg of dial turn to
focus. Based on the 34
binoculars in my test group, this is very SLOW focus for this close
3m-30m
range. The fast focus binoculars in my test group cover this same
distance range
with anywhere from 100-deg to 180-deg
of dial turn. Only ONE binocular I've measured
was slower focus than 300-deg in this range. Only the
Bushnell Legend and the Fujinon BFL are fast focus
in the range from 3m to 30m (10ft to 100ft), with little difference
between
them all.
All BUT two of these binoculars are fast focus in the range
from 30m to 100m (100ft to 300ft). The Oberwerk 8x56 and the Garrett
Classic 8x45 are slow focus in this
range.
FOV and Field Sharpness
Of the roofs, the Celestron Regal is 6.3-deg, the
Bushnell
Legend is 6.5-deg and the Garrett Apo is
6.7-deg. Several of the porros have a wide fov that
exceeds
8-deg. Most of the other have a fov
exceeding 6.5-deg. The fov of
the Oberwerk 8x56 is only 5.7-deg, the smallest of all
these.
The 8xRegal has by far the best sharp fov, what could be considered
sharp to
the edge fov, with only 1 arcmin total distortion all the way out at
95% of the
field. There are only four other
binoculars in these tests that could equal or exceed that mark. All
four are benchmark binoculars, two
Fujinons and two Nikon SEs.
Two porros with the best sharp fov are the Fujinon BFL and
the Pentax PCF WP II. Both have
85% sharp and 90-95% usable.
Field
of View degrees
|
spec
|
actu
|
calc
|
sharp
|
sharp
|
sharp
|
limit
|
Small
Binoculars
|
FOV
|
FOV
|
Afov
|
600arc"
|
1200arc"
|
fov |
fov |
Oberwerk
8x56
|
6.0
|
5.7
|
46
|
75
|
75
|
4.3
|
4.3
|
Garrett
Classic 8x45
|
8.3
|
7.3
|
59
|
70
|
70
|
5.1
|
5.1
|
Celestron
Regal 8x42 rp
|
6.5
|
6.3
|
51
|
95
|
95
|
6.0
|
6.0
|
Bushnell
Legend 8x42 rp
|
6.3
|
6.5
|
54
|
75
|
75
|
4.9
|
4.9
|
Garrett
DCF 8x42 Apo rp
|
7.0
|
6.7
|
54
|
70
|
70
|
4.7
|
4.7
|
Swift
Ultralite 8x42
|
6.6
|
6.5
|
52
|
75
|
80
|
4.9
|
5.2
|
Fujinon
BFL 8x42
|
6.5
|
6.5
|
52
|
85
|
90
|
5.5
|
5.9
|
Pentax PCF
WP II 8x40
|
6.3
|
6.3
|
50
|
85
|
95
|
5.4
|
6.0
|
Nikon
Action Extreme 8x40
|
8.3
|
8.1
|
64
|
60
|
65
|
4.9
|
5.3
|
Nikon
Action VII 8x40
|
8.2
|
8.15
|
64
|
60
|
65
|
4.9
|
5.3
|
Oberwerk
Mariner 8x40
|
8.4
|
8.0
|
64
|
70
|
70
|
5.6
|
5.6
|
Nikon
SE 8x32
|
7.5
|
7.6
|
61
|
95
|
95
|
7.2
|
7.2
|
It would seem that one design feature that contributes to a
high level of outer field sharpness is the use of very narrow Afov
eyepieces. For instance the 8xRegal have 51-deg Afov
eyepieces, low for any of these 8x binoculars. It has the sharpest
outer field image. Fujinon BFL (52-deg Afov) and the
Pentax
(50-deg Afov) are similar in that Afov is very narrow
and outer field aberration
is well controlled. These three
binoculars, even though they do not have the widest Total fov, do
indeed have
the widest usable fov of all in this list.
The Nikon AE and the Nikon Action deteriorate rapidly and
have only 65% of the fov usable, but since they start out very wide,
that does
result in more than 5-deg usable fov. The Oberwerk
Mariner, the Garrett Roof and the Garrett Classic only get
70% usable fov with 2 arcmin distortion. Both the Bushnell roof and the
Oberwerk 8x56 quickly fell off by 75%
out.
Two arcminutes of total distortion in your image provides no
more useful information. Stars are
either distorted blobs or long streaks. The image has lost perhaps two
full magnitudes of faint stars.
The Oberwerk 8x56 uses the narrowest Afov eyepieces of any
in this list, but do not fully capitalize on that feature. They end up
with the narrowest Tfov
of all these, and the narrowest
sharp fov and usable fov.
Curvature and Depth of Field
The Nikon Action Extreme, Nikon Action and Oberwerk Mariner
have the most field curvature. The
Bushnell Legend has the most field curvature of the three 8x42 roofs,
but less
than any of the porros first mentioned. The Bushnell has 1 arcmin of
curvature at 60% out in the field, and 90
arcsec at 90% out. The three
porros here all have nearly 2 arcmin of curvature at 60% out, and 2.5
arcmin at
90% out. The Fujinon BFL and the
Celestron Regal roof have very little curvature, the 8xRegal has almost
none.
Binoculars with more field curvature have greater apparent depth
of field in front of the focus point. It would seem therefore that a
field
flattener lens, which would be desirable for an astro viewer to get as
flat a
field as possible, might work against a terrestrial viewer looking for
the
greatest depth of field.
An astronomer would prefer all binoculars to have as little
field curvature as possible so the entire plane of the fov has as
little
distortion as possible. It is not unusual to find that a binocular with
much
less sharpness out at 60% or 70% in the fov has a much greater amount
of field
curvature than a binocular which appears sharp out to 80-90% of the
fov. A
terrestrial viewer might want to consider how field curvature affects
the view,
and may in fact find field curvature to be a useful aberration. While
it does
nothing to add to depth of field further distant than the plane of
focus, field
curvature provides for closer objects to appear in focus as they range
out
across the fov.
Depth of Field example:
The Fujinon BFL 8x42 has low field curvature (approx 15
arcsec curvature at 60% out, 25 arcsec at 70% out and still only 60
arcsec of
curvature at 90% out). Basically,
that's pretty close to a flat field.
When focused at 50m, objects at 40m appear sharper at 30% out in the
field and objects at 30m appear shaper at 50% out, but objects at 25m
are not
in focus and cannot be seen better anywhere in the field. I would say
the BFL has a narrow depth
of field.
The Celestron Regal 8x42 has even less field curvature than
the Fujinon BFL. When focused just
as the BFL in the test above, the Regal sees 30m appear shaper at 80%
out. No objects closer than that can be seen
clearly at any point in the fov.
The Bushnell Legend 8x42 has the most field curvature of the
roofs included here (45 arcsec at 60% out, 75 arcsec at 70% out, 100
arcsec at
90% out). When focused at 50m, objects at 40m appear sharper at 30% out
in the
field and objects at 30m appear shaper at 40% out. Objects at 25m are
seen clearly at 70% out in the field and
objects even slightly closer are seen clearly further out in the field.
The Nikon Action Extreme has field curvature of (50 arcsec
at 60% out, 120 arcsec at 70% out, 150 arcsec at 90% out). When focused
at 50m,
objects at 40m appear sharper at 30% out in the field and objects at
30m appear
shaper at 50% out. Objects at 15m
are seen clearly at 70% out in the field and objects even slightly
closer at
12m are seen clearly focused further out at 90% in the field.
The Nikon Action Extreme, decried in some circles for
it's
outer field aberrations, has one of the strongest measures of field
curvature
of all the 8s measured. The effect
is has on depth of field is dramatic. When the binocular is focused on
an object 200 yds distant, the fissures
and nodules in tree bark on trees at 60 yds can be studied in detail if
positioned at 50-60% out in the field of view. Water droplets hanging
from a tree limb at 30yds are seen
very clearly in focus at 80-90% out in the fov. When the same
experiment is conducted with the Fujinon BFL,
no detail can be seen in the tree bark at 60 yds from any position in
the field
of view and the branches with water droplets at 30yds are a blurry
mess.
From these tests it seems apparent perhaps the strongest
influence on depth of field in all binoculars is the amount of field
curvature
in the lens. Field Curvature, an
aberration frowned on by astronomers, can be one of the greatest assets
to a
terrestrial viewer.
Aperture
With a few noted exceptions most of these binoculars come
very close to the specified aperture. The 40mm Nikon Action prism shelf
stops the aperture down to 38mm. The Fujinon
BFL 42mm is stopped to 40mm. None of these have any significant losses
of the
light due to exposed prism edges or prisms interfering in the light
path.
You can see from the results in the data table, the three
different tests for aperture don't all
give the same results. Measuring exit pupil is difficult. In addition,
even though my dial
caliper can give readings to increments of 2/100ths mm, I round my
readings up
or down to the nearest 1/10
th mm, so that could
easily account for a
small difference in the three types of readings. Measuring the aperture
with a loupe is direct, but there is
some difficulty in obtaining readings that are any more accurate than
to a mm,
especially if the stop is a baffle in front of the prism, in which case
great
care must be taken to insure the proper reading is obtained. So more
potential slight variance now
exists. The laser is probably the
most accurate indicator, but once again, sliding the laser across a
glass plate
to each position at the edge of the aperture and recording fine
measurements of
that diameter is probably no more accurate than a mm. So
it's easy to have differences in the
readings from these
methods. However, none of the individual
methods should be off by more than a mm, and certainly none of the
methods nor
is the end result off by several mm.
Effective
Aperture
|
spec
|
spec
|
spec
|
actu
|
actu
|
Aper
|
Aper
|
Aper
|
Aper
|
chord
|
Net
|
Net
|
Small
Binoculars
|
Mag
|
Aper
|
pupil
|
Mag
|
pupil
|
pupil
|
loupe
|
laser
|
avg3
|
%loss
|
Aper
|
Aper
|
Oberwerk
8x56
|
8
|
56
|
7.0
|
8.1
|
6.0
|
49
|
47
|
47
|
48
|
0%
|
48
|
-15%
|
Garrett
Classic 8x45
|
8
|
45
|
5.6
|
8.1
|
4.8
|
39
|
38
|
39
|
39
|
2%
|
38
|
-16%
|
Celestron
Regal 8x42 rp
|
8
|
42
|
5.3
|
8.1
|
5.1
|
42
|
42
|
42
|
42
|
0%
|
42
|
-1%
|
Bushnell
Legend 8x42 rp
|
8
|
42
|
5.3
|
8.2
|
5.1
|
42
|
41
|
41
|
41
|
2%
|
41
|
-3%
|
Garrett
DCF 8x42 Apo rp
|
8
|
42
|
5.3
|
8
|
5.2
|
42
|
41
|
42
|
42
|
1%
|
41
|
-2%
|
Swift
Ultralite 8x42
|
8
|
42
|
5.3
|
8
|
5.1
|
41
|
41
|
41
|
41
|
0%
|
41
|
-3%
|
Fujinon
BFL 8x42
|
8
|
42
|
5.3
|
8.0
|
5.0
|
40
|
40
|
41
|
40
|
2%
|
40
|
-6%
|
Pentax
PCF WP II 8x40
|
8
|
40
|
5.0
|
8.0
|
5.0
|
40
|
39
|
38
|
39
|
1%
|
39
|
-3%
|
Nikon
Action Ex 8x40
|
8
|
40
|
5.0
|
7.9
|
4.8
|
38
|
39
|
40
|
39
|
0%
|
39
|
-3%
|
Nikon
Action VII 8x40
|
8
|
40
|
5.0
|
7.9
|
4.8
|
38
|
38
|
38
|
38
|
0%
|
38
|
-5%
|
Oberwerk
Mariner 8x40
|
8
|
40
|
5.0
|
8.0
|
4.0
|
32
|
32
|
31
|
32
|
0%
|
32
|
-21%
|
Nikon
SE 8x32
|
8
|
32
|
4.0
|
8
|
4.0
|
32
|
32
|
33
|
32
|
0%
|
32
|
1%
|
The noted exceptions with significantly reduced aperture are
the Oberwerk 8x56, the Garrett Classic 8x45 and the Oberwerk Mariner
8x40. All of these are stopped down to an
effective aperture 15% to 20% less than specified. Following are two
photos that show exit pupils compared to a
standard. The visual evidence is
unmistakable.
Here you see the Fujinon FMT-SX 10x50 on the bottom of both
photos. On the left is the
Oberwerk Mariner 8x40. On the
right are the Garrett Genesis 10x50 and the Garrett Classic 8x40. The
Fujinon has a measured exit pupil
of 4.9mm. By specifications, all
the other binoculars in these photos should have equally large or
larger exit
pupils compared to the Fujinon. It
is pretty easy to see the photos show that is not the case.
Baffles and Blackening
The Pentax PCF WP II 8x40 is well baffled and
blackened. Any internal metal is
very dark. There is no bright gray
metal between the objectives and the prisms. The baffles are very
closely sized to come as close to the
prism aperture as can be without interfering in the light path.
The Fujinon BFL is exceptionally well baffled and
blackened. All internal metal is
very dark. There is no bright gray
metal between the objectives and the prisms. The baffles are perfectly
sized to the light cone between
the objective and the prism aperture. The inner section of the
objective cone wall is fine ribbed to prevent
reflections on the inside of the wall.
The Regal interior baffles and blackening are pretty good.
There are two metal baffle rings and the inside wall is cut with ridges
and
blackened. There is some grey metal near the prism housing, but it is
pretty
dull grey. The baffles are near
perfectly sized when the binocular is focused at infinity. Because it
is internal focus and that
assembly is in front of the prism, and because the baffle size remains
constant,
it is therefore a bit undersized when it is moved forward to set the
binocular
for close focus.
The Nikon Action baffle is grossly undersized (the baffle hole
is too big). The light cone from the objective never comes near the
baffle before it hits the edge of the prism aperture. The inside of the
objective barrel is blackened, however all the metal around the prism
is bright gray.
Here on the right you see, the outer bright ring is the edge of the
aperture, the second bright ring is the baffle edge and the inner gray
ring is the prism aperture. On the left I have lined up the aperture
with the baffle. Notice how much of the prism shelf is exposed. The
objective aperture, the baffle edge and the prism aperture should all
line up.
The Nikon Action Ex baffle is also considerably undersized. The light
cone edge from the objective too the prism aperture should pass very
close to the edge of the baffle. The baffle edge is well outside the
diameter of the light cone. The inside of the objective barrel is well
blackened, however all the metal around the prism is bright gray.
The Garret roof and the Bushnell Legend roof have bright grey metal in
near the prisms. Just like the internal focus Regal, the Bushnell and
the Garrett baffle must be sized for when the binocular is focused at
infinity, which they are. The baffles become less and less sized
properly as the binoculars are adjusted towards close focus.
The Oberwerk Mariner 8x40 baffle is grossly oversized. The baffle ring
hole is too small for the light cone. It can easily be seen as the
culprit for reducing the effective aperture of the Mariner from 8x40
all the way down to 8x32.
An attempt is made with this photo of the Mariner to show the edge of
the objective lined up with the edge of the baffle. You should be able
to see the same side (the outer edge) of the prism aperture in the
background. It is dramatically cut off. In addition, take note of the
shiny surface (green reflection) at the entrance to the prism aperture.
There should not be any shiny surfaces anywhere in the objective cone
or near the prism aperture.
Coatings
All these binoculars appear to have multi-coated objectives and eye
lenses. Coatings should not reflect light. Coatings that reflect more
light have less light passing thru the lens.
The Celestron Regal by far appears to have coatings that reflect the
least amount of light. No other binocular here is similar to the
Celestron Regal. The Regal is similar to the Nikon SE and the Fujinon
FMT-SX
The Pentax PCF WP II is similar to the Regal in that it reflects very
little, ranked second best among this group. The Bushnell Legend roof,
the Oberwerk Mariner, Swift Ultralite and Fujinon BFL are all very
similar. They all have more reflection than the Pentax, but less than
the Nikon AE and Nikon Action.
Left: Celestron Regal 8x42 top, Bushnell Legend 8x42 roof, Pentax PCF
WP II 8x40 bottom
Right: Nikon Action EX 8x40 top, Oberwerk Mariner 8x40, Fujinon BFL
8x40 bottom
The Garrett Classic has nice coatings. Coatings are on a par with the
Oberwerk Mariner. Coatings are more reflective than the Pentax but less
reflective than the Nikon AE.
The Nikon Action Extreme and the Nikon Action coatings both reflect
more than the Pentax PCF WP II, Bushnell Legend, the Mariner or the
Fujinon BFL.
The Nikon AE lenses are multi-coated, however the prisms appear to be
only single coated, preventing that one from being labeled FMC. Yet the
Nikon AE see stars equally as faint as the Pentax and both of them see
slightly fainter stars than the Garrett Classic.
The Garrett Apo roof reflects a lot of light off the objective lens.
The difference here from best to worst is that it was very difficult
for me to see my reflection in the Regal and no detail at all could be
seen. In the Garrett, I could easily see facial features in detail and
could see the color of my shirt. In tests, the Garrett roof records the
lowest LM, possibly in agreement with a higher reflectivity in the
coatings. All these roofs are listed as FMC and phase coated.
The Bushnell has
"rainguard"
coatings. If you've ever used rainguard
applied to your windshield, you know it virtually eliminates the need
to use wipers in the rain. This coating is intended to do the same on
the Bushnell.
Limiting Magnitude
With a variety of observations from different nights, I compiled a list
of the best Limiting Magnitude for each. The best out of this group are
the Oberwerk 8x56, the Regal, the Bushnell, the Pentax and the Nikon
AE, all of these reached a limit of mag 9.6. I never saw stars deeper
than mag 9.1 with the Garrett Apo, the Nikon Action or the Oberwerk
Mariner. With the exception of those binoculars that never saw any
deeper than mag 9.1, all the other binoculars saw between mag 9.4 and
mag 9.6. Typically these better 8x binoculars see about
½ magnitude less than a good 10x50.
Prism Vignette and Illumination
Light transmission is dependant on more than just good coatings.
Excellent coatings and poor internal beam transfer can result in poor
output. On the other hand, excellent beam transfer and illumination,
even with less than premium coatings may result in a binocular that
appears brighter and sees fainter objects.
The Garrett roof, the Regal roof and the Bushnell roof all gave very
good readings for control of internal vignette and lack of tilt in the
light path. None of the above had any significant tilt and all showed
very good transfer of the test beam into the exit pupil. The Oberwerk
8x56 the Garrett Classic 8x45, the Swift and the Pentax showed poor
readings, all showing some tilt in the light path and considerable
vignette of the beam before it reached the exit pupil. In both
instances, even with the test beam in the very center of the objective
lens, large portions of a 5-deg beam were cut off and
never reached the exit pupil. No position could be found on the
objective lens where the entire beam would pass to the exit pupil.
Normal function shows the entire 5-deg wide circle and
crosshairs laser target pattern will pass thru when the test beam is
placed perpendicular to the optical axis and anywhere within the
central 20-30% of the objective lens. The Fujinon BFL 8x42 set the
highest standard for superior function by transmitting the entire beam
pattern from every point in the central 50% diameter of the objective
lens. The Pentax roof and the Oberwerk roof had the lowest scores for
internal prism vignette of all binoculars tested in this study.
Light
Transfer
|
tilt
|
tilt
|
100%
|
75%
|
Exit
|
MAX
|
LM best
|
Small
Binoculars
|
left
|
right
|
beam
|
beam
|
Pupil
|
Lux
|
5.2-5.4
|
Oberwerk
8x56
|
15
|
15
|
0
|
50
|
6.0
|
870
|
9.6
|
Garrett
Classic 8x45
|
10
|
15
|
0
|
60
|
4.8
|
770
|
9.4
|
Celestron
Regal 8x42 rp
|
10
|
10
|
10
|
50
|
5.1
|
579
|
9.6
|
Bushnell
Legend 8x42 rp
|
4
|
3
|
15
|
55
|
5.1
|
560
|
9.6
|
Garrett
DCF 8x42 Apo rp
|
10
|
2
|
35
|
55
|
5.2
|
660
|
9.1
|
Swift
Ultralite 8x42
|
15
|
10
|
0
|
55
|
5.1
|
630
|
9.5
|
Fujinon
BFL 8x42
|
7
|
3
|
50
|
70
|
5.0
|
751
|
9.4
|
Pentax
PCF WP II 8x40
|
25
|
20
|
0
|
40
|
5.0
|
770
|
9.6
|
Nikon
Action Extreme 8x40
|
5
|
5
|
30
|
60
|
4.8
|
880
|
9.6
|
Nikon
Action VII 8x40
|
10
|
0
|
25
|
50
|
4.8
|
810
|
9.1
|
Oberwerk
Mariner 8x40
|
0
|
0
|
30
|
45
|
4.0
|
630
|
9.1
|
Nikon
SE 8x32
|
2
|
2
|
25
|
60
|
4.0
|
603
|
9.1
|
The Oberwerk 8x56, the Nikon AE and the Nikon Action appear to have
high marks
for illumination of the exit pupil. However, generally, as seen from
the data in the entire list of 34
binoculars, max lux appears to trend higher for a larger exit pupil.
Therefore the larger exit pupils should
have higher readings. The Oberwerk
8x56 scored well, as did the Nikon AE and Nikon Action. The roofs all
scored typically low in
this test.
Resolution
Normal resolution covered a fairly narrow range, with almost
all thse binoculars doing fairly well. The Nikon AE and the Fujinon BFL
both recored the best values at 81
arcsecconds apparent and the Pentax a very close 82 arcseconds. The
Garrett Classix the worst at 92
arcseconds and the Oberwerk 8x56 could reach only 88 arcsec, but that
fairly
respectable.
Boosting the resolution test power by 6x normal, the Pentax
was able to see the finest resolution at 187 arcseconds. 3.8 arcseconds
for an 8 power binocular
is really exceptional. The
Celstron Regal was able to see 4.1 arcseconds for an apparent
resolution of 204
arcsec. The Celestron Regals have some
of the best boosted resolution in the entire study, but here in the 8x
group
the Pentax is the standout with some of the best all around resolution
readings
across the board.
The Bushnell Legend, the Fujinon BFL and the Oberwerk
Mariner put up the best figures for handheld resolution. In fact, the
Bushnell Legend is the
only roof among the top group for handheld resolution, all the rest are
small
porros.
Resolution
USAF chart
|
actu
|
USAF
|
apprnt
|
boost
|
USAF
|
apprnt
|
USAF
|
apprnt
|
Small
Binoculars
|
Mag
|
res
|
res
|
Mag
|
x6.15
|
res
|
res
handheld
|
Oberwerk
8x56
|
8.1
|
10.8
|
88
|
50
|
6.8
|
339
|
15.3
|
124
|
Garrett
Classic 8x45
|
8.1
|
11.5
|
92
|
50
|
6.8
|
338
|
15.3
|
123
|
Celestron
Regal 8x42 rp
|
8.1
|
10.3
|
83
|
50
|
4.1
|
204
|
16.0
|
130
|
Bushnell
Legend 8x42 rp
|
8.2
|
10.3
|
84
|
51
|
5.4
|
274
|
14.5
|
119
|
Garrett
DCF 8x42 Apo rp
|
8
|
10.8
|
87
|
49
|
5.4
|
266
|
15.3
|
122
|
Swift
Ultralite 8x42
|
8
|
10.8
|
86
|
49
|
4.8
|
236
|
16.2
|
130
|
Fujinon
BFL 8x42
|
8.0
|
10.3
|
81
|
49
|
4.6
|
223
|
14.5
|
115
|
Pentax
PCF WP II 8x40
|
8.0
|
10.3
|
82
|
49
|
3.8
|
187
|
15.3
|
122
|
Nikon
Action Extreme 8x40
|
7.9
|
10.3
|
81
|
49
|
5.4
|
262
|
15.3
|
121
|
Nikon
Action VII 8x40
|
7.9
|
10.8
|
85
|
48
|
6.8
|
329
|
15.3
|
120
|
Oberwerk
Mariner 8x40
|
8.0
|
10.8
|
87
|
49
|
5.1
|
251
|
14.5
|
116
|
Nikon
SE 8x32
|
8
|
10.8
|
87
|
49
|
5.7
|
282
|
15.4
|
123
|
Observing
M1 M78 observations
A few extended object comparisons are included here to give
some indication of the ability of these instruments to deliver on low
contrast
objects.
M78 under mag 4.9-5.0 skies
Fujinon 10x50, M78 was immediately visible. Central stars are not seen.
Nikon Action 10x50, not easy but was seen OK.
Celestron Regal 8x42 roof, it was just barely seen
Could not find it in any binocular handheld.
M78 under mag 5.0-5.2 skies
Once I pinpointed its location, I could just barely detect it in
10x50s.
In a Nikon SE 10x42, M78 was easy.
Celestron Regal Roof 10x42 it was not easy but was seen OK.
Bushnell Legend 8x42 Roof, just barely seen
M78 seen in all, but with difficult at 7x and 8x.
Saw M78 in Bushnell handheld braced.
I did not see it at all in the 8x42 BFL.
M78 under mag 5.2-5.4 skies
Leupold WR Mesa 10x50, seen good,
Nikon AE 10x50, seen good,
Nikon Monarch ATB 10x42 Roof, also seen good.
Bushnell Legend 8x42 Roof, seen averted
Oberwerk 8x56 (8x48), just barely seen
Pentax PCF WP II 8x40, just barely seen
M1 under mag 4.9-5.0 skies
Fujinon 10x50, M1 was seen only after concerted effort and chart
reference.
Nikon Action 10x50, took repeated tries to find it, even averted.
Celestron Regal 8x42 roof, took even more time and when I did suspect
seeing it
with averted vision, it was questionable.
Not seen in any handheld or braced.
M1 under mag 5.2 skies,
It was not seen at first. But after locating it in a 15x70,
it was a bit easier to detect in the 10x50s. It was barely detected
with great
difficulty in the BFL 8x42.
M1 under sky mag 5.2-5.4
Oberwerk Mariner 8x40 (8x32) M1 barely seen
Pentax WPII 8x40 M1 barely seen
Nikon AE 8x40 M1 not seen
Nikon Action VII 8x40, M1 not seen
Front row: Nikon SE 8x32, Garrett Apo 8x42 roof
Second Row: Celestron
Regal 8x42 roof, Oberwerk Mariner 8x40
Third row: Bushnell Legend 8x42 roof, Garrett Classic 8x45,
Fujinon BFL 8x42
Back row: Nikon Action 8x40, Nikon Action Extreme 8x40,
Pentax PCF WP II 8x40
Summary
Nikon Action 8x40 – 8x38,
8.15-deg, er=11mm, IPD=56-73, cf=11ft,
fmc/fc
The Nikon Action has the widest fov 8.15-deg, has very
good normal resolution, but
has very poor boosted resolution. Outer
fov sharpness is good to only 60% and deteriorates to poor by 65%, but
that
gives a 5.3-deg usable fov. It has no
functioning internal baffles and is poorly blackened. However, it does
illuminate the exit pupil very well and
internal vignette is well controlled. Yet LM maximum is mag 9.1,
possibly due to reduced contrast and less
than optimum coatings. It is poor
mechanically and ergonomically, with a wobbly eyepiece bridge and the
shortest
eye relief of 11mm. Mechanical
build quality, very short eye relief, poor outer fov, lack of good
baffles and
slightly reduced aperture all lower the score on this one. It scores in
the middle overall.
Garrett Classic 8x45 - 8x38, 7.3-deg, er=18mm,
IPD=59-74, cf=15ft, fmc/fmc
The Garrett Classic looses significant points for the
reduction of aperture. Resolution is the worst of the 8x binoculars.
Delivery of light is unbalanced and has
significant vignette, but the coatings and the exit pupil illumination
are good.
Field sharpness falls off immediately after 70% giving a net result
5.1-deg usable
fov. IPD is limited to 59mm. Quick loss of field sharpness,
significant reduction of aperture, significant vignette, and poor
resolution
move the total score to near the bottom of the list. Not recommended.
Oberwerk Mariner 8x40 – 8x32,
8.0-deg, er=16mm, IPD=62-73, cf 15ft,
fmc/fmc
The Mariner is stopped down by internal baffles that have much too
narrow an
opening. The 8.0-deg fov makes it one
of the widest, but it reaches sharp limt at 70% and falls off
immediately
afterwards. Usable fov of 70%
means it has a 5.6-deg usable fov. Resolution
is average and handheld resolution is very good. The Mariner scores
well for lack of internal vignette high
for illumination of the exit pupil. The low limiting magnitude results
reflect significantly reduced
aperture. Narrow limit IPD of 62mm
is the worst of all binoculars. Due primarily to dramatic reduction in
aperture
and quick fall off of usable field, the Mariner scores are lowered.
However, its still in the middle of the
pack. Were it not for the dramatic
reduction in aperture and the accompanying loss of illumination and LM,
this
binocular would score respectably in the average range of all 8x40s.
Not recommended for children.
Oberwerk 8x56 -
8x48, 5.7-deg, er=21mm, IPD=59-72, cf=30ft, fmc/fc
This Oberwerk has the narrowest fov of all the 8s,
5.7-deg. The field is sharp to 75% but not
usable beyond 75%. Usable fov is only 4.3-deg. It has
one of the greatest amounts of aperture reduction due
to mis-sized internals. It has
significant internal vignette and poor illumination of the exit pupil.
It has average normal resolution, but
very poor boosted resolution. LM
reflects the reduced aperture and vignette. Significant loss of points
in almost every category
places this one near the very bottom of the list. Not recommended.
Swift Ultralite 8x42 – 8x41,
6.5-deg, er=19mm, IPD=51-76, cf
20ft, fmc/fmc
It has good fov at 6.5-deg, sharp out to 75% and usable
to 80% for a good net
usable fov of 5.2-deg. Not
waterproof. It has one of the
widest ranges of IPD of all binoculars. Resolution is average, however
handheld resolution is poor. There is internal vignette and light
transfer is poor. The Swift loses
most of its points for poor resolution and internal vignette. Still,
overall score is average.
Pentax PCF WP II 8x40 – 8x39,
6.3-deg, er=13mm, IPD=57-74, cf 11ft,
fmc/fmc
It has one of the highest percentages of sharp and usable field of
view. 85% sharp, 95% usable, gives a 6.0-deg
usable fov one of the widest measured. Has adjustable twist eyecups,
focus lock. Coatings are very good, rank among the best. Resolution is
excellent. It has issues with internal tilt and
vignette, but illumination is good. LM is good. Mechanically
very good. The Pentax loses points
for vignette and narrow depth of field. A very good performer, it ranks
near the top of the list. Recommended.
Bushnell Legend 8x42 Roof – 8.2x41,
6.5-deg, er=17mm,
IPD=58-74, cf=7ft, fmc/fmc-p
The Bushnell is fast focus and weighs 25oz. I especially like the
contoured shape of this binocular and
found it to be one of the most comfortable handheld. Everything works
easily and does what it is supposed to do,
providing a wide range of adjustability for different users, although
IPD could
be tight for children. It has
moderate marks for field sharpness, but it has the widest usable fov of
the
roofs next to the 8xRegal. Good
coatings. Contrast was not as good
as the Regal. It shows very good
resolution and gave one of the highest marks for handheld resolution.
The Bushnell may not be the best in any
category, but it does a lot of things very well and
doesn't do anything really
poorly. Among all 8xs, recommended
for both terrestrial or astronomy.
Garrett DCF 8x42 ApoRoof - 8x41, 6.7-deg, er=19mm,
IPD=57-71, cf=5ft, fmc/fmc-p
Widest fov of all the roofs. no
false color at all, bright image, one eyecup constantly changed
position needed
to reset it every time I used it. No pincushion at all, may reduce
desirability
for terrestrial use. Very compact, very comfortable to carry around.
Has nice image and ample eye relief. All resolution values are good and
shows
little axial tilt and transmits internal beam well, indicating little
internal
prism vignette. Looses points for
lack of wide sharp fov, low LM, loose eyecup and difficult diopter.
Still a good performer. Except for the finicky eyecup, I enjoyed
this one for terrestrial use. If I
wanted to see the faintest stars, I'd
pick another.
Celestron Regal 8x42 Roof - 8.1x42, 6.3-deg, er=17mm,
IPD=58-74, cf=6ft, fmc/fmc-p
The 8x42 Regal has ample eye relief and coatings are among
the best. The Regal 8x42 has
almost no field curvature and has one of the widest usable field of
view of any
binocular in this entire study. It
is slow focus at close range, but fast focus otherwise. The internal
vignette test shows a
perfectly balanced image with little to no vignette. Illumination is
good. LM shows near equal to some of the best 10x50s. Resolution is
excellent. The 8x42 Regal is an outstanding
astronomy binocular for its ease of use at the eye, excellent contrast,
deep
limit and low aberration wide field. I suppose these are all attributes
that would make it a good terrestrial
binocular also.
Nikon Action Ex 8x40 - 8x39, 8.1-deg, er=14mm,
IPD=56-73, cf=13ft, fmc/fc
The Nikon AE is sound mechanically and has good ergonomics. Normal
resolution is excellent. Boosted resolution is OK, not one of
the best. Handheld res is very
good. The aperture shows only
minor reduction. Coatings do not
rank as the best. Internal
vignette is very well controlled, exit pupil is balanced and
illumination is excellent. There are no internal reflections. Limiting
magnitude scores well. Outer field sharpness falls off at 60%
out, and is fair only out to 65%, but that still gives a
5.3-deg usable fov. Curvature contributes to a very
wide
range of depth of field. Eye
relief is sufficient at 14mm. There
is no chance of hitting the well recessed eye lens with your
eyeglasses. Eye cups are widely adjustable and IPD
covers a wide range. Diopter is
very easy to adjust. Overall, the
Nikon AE scores the highest of the 8x40s, but not by much over the
Pentax PCF
WP II, Celestron Regal or Fujinon BFL. Each does some things slightly
better than the other. Strongly recommended.
The
Nikon Action Extreme 8x40, shown here with both the AE10x50 and
AE12x50, has
exactly the same prism housing and eyepiece assembly, except perhaps
for
eyepiece focal length. The major
difference is it has smaller objective cones. This is similar with
almost all families of binoculars and can
be seen with the Garrett Classics,
the Oberwerk Mariners and the Nikon SEs.
A few words about the benchmarks:
Nikon SE 10x42 - 10.2x42, 6.2-deg, er=17mm, IPD=53-74,
cf=13ft,
fmc/fmc,
Very light at 24oz. (680g). No false color noticed. Very little field
aberration, but mild curvature. Quite comfortable handheld, ample eye
relief, not as much blackout issues as the 12x50SE. Relatively fast
focus 30m-100m, but slow focus 30m-3m. Interior baffles and blackening
is
excellent, no internal reflections. Reaches the same LM as the
10x42Regal, the deepest of the roofs and
better than many 10x50s. Extended object contrast is superior, better
than the 10xRegal. Measures near best in normal power on-axis
resolution, 6x boosted resolution and handheld resolution. Nearly sharp
to the edge, usable field
of view about 90% fov. Not waterproof
. Aperture is true 10x42 and
system shows very good transfer of light beam. Coatings are among the
best made.
Fujinon BFL 8x42 - 8x40, 6.5-deg, er=11mm, IPD=57-73,
cf=14ft,
fmc/fmc
Very light at 24oz. (680g). No false color at all, no field curvature
at all, very light
and comfortable, although it would be nice if eye relief were about
2-3mm
longer. In the short range, they
are faster focus than any of the roofs. Just barely enough eye relief
for me to use with my eyeglasses. Very
well baffled interior of objective tubes, no internal reflections. Has
one of the best on-axis resolution marks
but also they hold up to show some of the best 6x boosted resolution
AND they exhibit
some of the best outer field sharpness. Focuses stars to very fine
pinpoints. These are waterproof, nitrogen purged,
aluminum alloy construction. They
have a lifetime warranty. Right
eyepiece has a clickstop diopter adjustment, very positive. The 8x42BFL
are very comfortable in the
hand, and at the eye. Right up to the eye, quick to grab the view, easy
and
quick to focus.
Some of these roofs make excellent astronomy
binoculars. The Celestron 8xRegal
and the Bushnell Legend 8x42, are good choices. As a bonus, these
choices equip the user with a nice
lightweight piece that can be used for terrestrial use. The Nikon
Action Extreme, the Fujinon
BFL and the Pentax PCF WP II all score very high for the 8x porros.
After that, the rest of the porros are
quite a ways down the list. The
Oberwerk 8x56 and then the Garrett Classic 8x45 scored 2nd
and 3rd
from the bottom of the entire list of 34 binoculars tested.
Clear skies, and if not, Cloudy Nights
edz
