Optics

The very next set of optics you should purchase, after your eye glasses, should be a decent set of binoculars.  Nothing says safety like avoiding trouble in the first place.  If you can watch from a distance, you may be able to avoid a lot of heartache latter.  It doesn’t matter if you are looking for wild game or running surveillance on what is going on around your own home or retreat, you can’t properly react to what you can’t see.  If you needed to get from point A to point B under severe conditions, it is better to scan the area as best you can for additional threats.  The further out you can spot those threats the better.  Often the best way to survive is not being seen or found.  In every book I have read on survival, binoculars have always come into place to create a tactical advantage whether it is putting game on the table or saving your own bacon.  So buy the very best you can afford and don’t skimp on quality.  Let’s go over some binocular basics so that you will choose the right pair for the task at hand.  One of the first requirements of a good set of binoculars is that they must be waterproof.  You never know what kind of action they may see so make sure that they will at least pass that test.  The next thing I would look for is what they call armor coated or rubberized so that they can take on a little more punishment.  Again, this is to protect your investment in what could be a piece of equipment that will last many years.

PRISMS:

After you take into account the different sizes, i.e. 8x42 compared to 10x50, the most significant difference it which type of prism do you pick.  The binoculars that use the Porro prisms are the ones we are all most familiar with.  These are the ones that have the offset from the lens to the eye piece.  The advantages of the Porro prisms are that there are many more models to choose from and the costs are more in line with what most people are willing to spend.  One could argue that you can get more bang for the buck by going with a set of binoculars that incorporate the Porro prisms.  Porro prism binoculars have a single pivot point between the two lenses making them easier to adjust the distance between your eyes.    While it is true that they deliver the best value for the dollar, they also have some drawbacks.  From reading several reviews on binoculars while looking for the “best” set for the money, I noticed that many times customers reported that the waterproof and fog proof attributes either flat out failed or over time ceased to exist.  It is also hard to find a suitable set of offset binoculars that are truly compact, or maybe we should say as compact as they could be.  If you purchase a set of binoculars that use Porro prisms, then hold out for what they call BAK-4 prisms as they are considered the best right now.  Some use a BAK-7 prism, but they just aren’t as good as the 4’s.  Generally speaking, it is easier to find better optics and by that I mean better coated optics as the cost for manufacturing can be spent on the glass and not the prism.  My guess is because this design has been around for decades and thus the options are greater.

Now let’s look the other option in prisms.  That is the roof prism.  These are found in the binoculars that cost a little more and in some cases, a lot more.  Roof prism binoculars can be spotted from across the room.  This is because the lens for each eye is lined up to for a single tub for each side of the binoculars.  By design, it is easier for companies to ensure that they are both waterproof and fog proof.  Also because of the straight tubes, you end up with a more compact set of binoculars.  Compactness may not matter while pulling your time in the Listening Post/Observation Post, but if you are on the move, it will matter a lot.  Because of the straight tubes, it is a little more difficult to adjust these for the spacing between the eyes.  The biggest downside I see is that you get a really good set of roof prism binoculars; you have to get in that $300 and up range.

What do the numbers mean?

The next thing to decide is which size do I need?  Binoculars are often classified as compact, mid-size, full-size, and zoom or astronomical.  For our purposes, we’ll pass on the astronomical as we would rather spend the money on something else, maybe another pair of binoculars.  As with any other tool, each size was designed for a specific task.  I would recommend that you own two pair, one compact and one full size.  

To understand how they are sized, you should understand what the numbers mean.  When you see a set advertised as 8x42, the first number represents the number of times an image is magnified when you look through them.  The second number is the size in millimeters that the objective lens or the lens opposite the eye.  

Be careful of not getting caught up with buying the biggest set of numbers you can.  The higher the first number or magnification is, the harder it will be to keep them focused on something.  

Get something in the 12x range or higher and it will feel like you have the shakes if you look through them too long as it will detect the slightest movement in your hands.  

Experts suggest that you stay with something in the 7 or 8 range for your first number.  

The second number is just as important.  Bigger is better but you will also be giving up the compactness of them as they will weigh more as that lens gets larger.  The larger this lens, the more light that goes into the binocular and the sharper the image will look.  This is called the exit pupil.  The actual diameter of the exit pupil is easy to compute.  You take the second number and divide it by the first.  For example, a pair of 8x42 binoculars will have an exit pupil of 5.25mm.  For a comparison, the human eyes in excellent condition have about a 7mm pupil opening.  So the closer you can stay to that number the more you’ll see even in dim light.  

What does this mean?  With all things considered equal, a compact set of binoculars in 8x21 would be better than a set of 12x25.  The 8x21 set would have an exit pupil of 2.63mm while the 12x25 would be 2.08mm.  You’ll be able to see more at dusk with the 8x21 than with the 12x25.  This may seem backwards as the magnification is 33% more (8 vs. 12), but without enough light entering the front of the lens, your eyes can’t process the images correctly.  

Still we haven’t answered the question of what size to buy.  I would suggest a pair of 7x50, giving you an exit pupil of 7.14 which is great, and a pair of 7x35 or 8x40 giving you an exit pupil of 5.00 each.  I would treat the later as my compacts and the former as the full-size binoculars.  Some compacts that are in the 10x25 range will only give you an exit pupil of 2.5 so don’t expect to see much unless it is the middle of the day.

ACCESSORIES:

Now that we have given you some ideas for binoculars, we need to talk about accessories.  The first thing I would purchase would be a decent case to keep them in.  After that and probably just as important, I would upgrade the neck strap.  I am partial to the ones like Cabela's or Bass Pro Shops sell that are part neck strap and part harness.  The harness system keeps you binoculars from bouncing and banging around while you are walking/running.  They keep them strapped close to your chest and easy to access.  I would also purchase a lens cleaning pens to keep the lens clean and free from scratches.

What do I have:

I have a 7 x 50 JENA by Carl Zeiss. This is a Monocular and works very well for me. It is the same size as a regular binocular but just cut it in half. 7 x 50 provides a exit pupil of 7.14. A really good exit pupil ratio. 

monocular is essentially half of a pair of binoculars, or a very simple telescope. Using prisms and lenses, a monocular allows the user to view objects at a distance as though they were much nearer. Through the use of two prisms, the resulting image appears in the correct orientation. This is in contrast to most telescopes, in which the image is inverted.

monocular is both lighter and smaller than an equivalent pair of binoculars, making it ideal for certain uses. The fact that, like a telescope, it must be used with only one eye introduces a number of problems that make binoculars preferable in many situations. The stereoscopic effect, which is achieved by using both eyes to view an object, allows for much better tracking of moving objects. It is for this reason that binoculars are preferred for following races or for tracking aircraft or birds in the sky.


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