A Test & Evaluation of the Bushnell Marine Binoculars
by J.B. Hohlfeld
Several months ago, Aaron Zelman sent us a couple of optical items that he
wanted us to field test for him. One of those items was a pair of the 7x50mm
Bushnell 'Marine' binoculars, Model #13-7500.
Straight out of the box, I thought I was looking at a pair of the old Tasco
binoculars which we had tested ten years ago. Though there are similarities
with the Tasco's, there are also some very big differences, which our field
testing proved out.
Square one, the Bushnell Marine binoculars will not fit into your shirt pocket,
or even into a cargo pocket on your BDU's. At eight inches wide, by seven
inches long, by two and three quarter inches thick, these are full size
military style binoculars, which are also two and one half pounds in weight.
The best way to utilize these binoculars is at a fixed position, ie:
stake-out position, or an OP/LP type position.
To aid you in field carry, Bushnell provides a large padded carry case with a
shoulder strap. Bushnell also provides a neck strap, which helps you in the out
of the case carry/observation mode.
A quick tour of the out side of the Bushnell Marine binoculars gives us the
following: (1) The objective lenses are a full 50mm inside diameter, with a
plastic dust cover for each objective lens. Since the lens covers are not
attached to the binoculars, be careful not to lose them. (2) The eyepiece/focus
lenses at the rear of the binoculars have a one piece lens cover system, which
is attached to the neck strap, so no problem losing it. The inside diameter of
the eyepiece lenses is 16.5mm for each eyepiece lens, which means that the
potential light transmission capabilities of these Bushnell binoculars is
excellent. Do not look for a center focus drum on these binoculars, there isn't
one. Each eyepiece is individually rotated for proper focusing, which can be a
bad thing for you, but a plus for someone like me because I normally focus each
eyepiece for a different distance, ie; I'll set the right 'monocular' for
objects at 100 meters, and the left 'monocular for objects which are at 200, or
300 meters. I've used this system for many years and it works great for me. You
will have to test it for yourself and go with what works for you. (3) When you
look at the top of the Bushnell Marine binoculars, you will see three
'buttons'. The white 'button' is actually a small translucent plastic 'window",
which allows light to pass into the binoculars during daylight hours. The next
'button' you will see, has a coin slot in it, because this is the battery
compartment access cover. The final 'button' you will come to, is actually a
button, which controls an internal light diode for night usage of the
binoculars.
Having completed the outside tour of the binoculars, let's take a tour of what
we have inside the binoculars. When you look through the eyepieces, you will
notice two things: (1) There are vertical and horizontal lines (scales), in
your direct field of view. (2) When you look at the six o'clock area of your
field of view, there is a 'window' which allows you to look at a floating
compass bezel. The obvious question about the compass is, is it just a sales
gimmick? Quick answer NO, it is not a sales gimmick. It is a real compass,
which you can use as a real compass. Here is my opinion on compasses in
general: (1) Any type of compass, is better than not having one at all. (2)
Anyone putting out to sea, or going into the bush, should have a map and
compass - Period. Example: Here in the mountains of northern New Mexico, we
lose an average of 3-4 day hikers per summer, who went off looking for a hidden
fishing hole, or the panoramic view, or Bambi. Because they did not have any
type of compass, they end up as part of the food chain.
Earlier, I mentioned that when you look through the eyepieces of the binoculars
you also see vertical and horizontal scales (lines). If you know the proper
formula, you can use these scales to determine your distance from an object, or
you can determine the height of an object. Before we get into exactly how to
use the scales in the Bushnell Marine binoculars, we need to take a side trip
into history. We know that there are 360 degrees in a circle and/or 360 degrees
on a compass bezel. For Napoleon's artillery people, the degree was not
accurate enough, ergo, they subdivided the existing circle/compass bezel into
6,400-MILS. The end result was much greater accuracy for their vertical or
horizontal cannon shifts during battle. Here is what we need to know about the
MIL:
One-MIL of angle is equal to approximately 1.8 meters, at a distance of 1,000
meters. For us, 1.8 meters translates to 72 inches in height, or in ground
distance, at 1,000 meters. Moving back to the Bushnell Marine binoculars, we
notice that there are small 'tick marks' on both the vertical and horizontal
scales. Bushnell tells us that there is a 5 MIL angle between each of these
'tick-marks' and that we can easily compute our distance from the local light
house by using their MIL scales. Local Lighthouse? Obviously, we have a
shortage of lighthouses in the Rocky Mountains, ergo, we had to come up with
something else. Assuming that someone is 72 inches tall, when you 'bracket'
them between the 5 MIL 'tick-marks', their distance from you is approximately
183 meters (200 yards). If our 72 inch person fits into one half of the 5 MIL
'bracket', they are about 732 meters (800 yards) from you. If you are
attempting to estimate the firing distance to Bambi with these binoculars, good
luck!
In my opinion, Bushnell is missing out on a larger market share by not having a
'Ground' version of these binoculars, ie; they can use the same binoculars, but
change the vertical and horizontal MIL scales to 1-MIL increment, so that any
hunter could use them to calculate their ground distance from Bambi. One last
item regarding the compass and MIL scale reticle. They are both housed in the
Left Monocular Tube, ergo, do not damage the left tube!
It's field testing time... According to Bushnell, their Marine binoculars are
waterproof, so you know what our first test was! Yep, into a bucket of water
for 72 hours. They had a tenancy to float, but the addition of a 5-LB weight
plate cured that. At 72 hours we took them out of the water, shook them off,
and saw the world clearly. No problem there. Since it was still winter here
when Aaron sent us his binoculars, the fogproof test was also very easy to do.
We put his binoculars into a snow bank for four days and nights. The average
daytime temperature was about (+) 45 degrees, with the nighttime temperatures
at (-) 19 degrees (F). Bottomline, the Bushnell Marine binoculars are fogproof
too. A point to remember regarding any glass optics and fogging. When you move
glass optics from a warm building to the cold outdoors, you will get moisture
freeze on the outer lens surfaces. By the same token, when you move from cold
to warm, you will get moisture condensation (water fog), on the outer lens
surfaces. The Bushnell binoculars exhibited all of the above during field
testing. Knowing this, what is the best way to deal with it? If you can, leave
your binoculars, or rifle scope, out in the cold.
While I am on the subject of glass optics, I need to remind you of a few things
regarding your binoculars, or rifle scopes. Here at Ranger Outreach Center, we
teach two levels of Precision Rifle. One level is open to the general public,
while the advanced level is restricted to Police/Military only. We have worked
with glass optics quite a bit over the years, so here are a few tips:
1.
DO NOT over clean your glass optics. Remember your optics are only as good as
the lens 'coating' which is applied to them at the factory. The lens 'coating'
is on the outside surface of the lens, ergo, protect it and do not over clean
it.
2.
We DO NOT recommend the use of 'lens paper', because it is too easy to rub too
hard/too long, and cut right through the 'coating' on your lenses, thereby
creating a peperweight. For all of our glass optics, we use Kodak liquid lens
cleaner and very well laundered cotton t-shirt, or soft cotton Q-tips. When in
doubt, go see the professionals at your local camera shop.
3.
When you are out in the bush try to keep your lenses covered until you have to
bring them into action. If you do get some dust/dirt on your lenses, gently
blow across the lens to get the objects out of your field of view. If possible,
carry a small camera 'air-brush' combination tool with you. They work great.
Back to field testing Aaron's Bushnell binoculars!
Due to the nature of the SWAT field training we do here at R.O.C., we don't use
binoculars which are as big as the Bushnell Marine binoculars, ergo, the only
binoculars we could test the Bushnells against were a pair of Minolta 8x30mm
compacts, and a pair of Leupold 10x25mm compact. Obviously, since the Bushnells
are a 7x50mm configuration, we could not do across the board comparison, but we
could check for clarity of light transmission and quality of lenses.
Bottomline, the Bushnells were excellent.
In an attempt to do a direct comparison, I loaned Aaron's Bushnell binoculars to
a good friend of ours, Deputy Sheriff Ruben Saiz. The only guidance I gave to
Ruben was, use them as you normally do in your police work, and try not to
break them! After a couple of weeks Ruben and I got together to discuss his
thoughts on the Bushnell binoculars. For years, Ruben has been using a pair of
7x50 military binoculars, and for years he though his binoculars were 'fit for
duty'. The easiest way to give you Ruben's reaction to the Bushnell binoculars
would be this, "Do I have to give them back to Aaron"? Ruben really likes the
Bushnell binoculars!
Ruben was amazed at the brightness and clarity of view in the Bushnells,
compared to his military binoculars. He also found the built in compass very
handy in directing 'spotter' aircraft over suspected drug field locations, day
or night. Bottomline, Deputy Sheriff Ruben Saiz would love to have a pair of
these binoculars for his police duties (that's a big hint Aaron!).
During all of our field testing, everything on the Bushnell Marine binoculars
worked. We had no problems with the compass bezel 'hanging up', or not moving
freely. We had no problem seeing the compass or the reticle, day or night. We
had no problems with the battery, which surprised us considering the cold
nights it went through in the backyard! We give the Bushnell Marine binoculars
a solid THUMBS UP.
Shortly after I wrote this article, Deputy Sheriff Ruben Saiz died. We was a
good man, he was a good friend, he was a damn good 'Street Cop'. We will miss
him.
If you have any comments you may write to:
R*O*C
P O Box 1164
Pecos, NM 87552
Fax: 505.757.8456
E-Mail: shohl@Pecos-nm.com
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