Survival UK Forums

Okay, hidey-ho campers.

Time for a little bit of help with getting to grips with optical enhancing equipment, e.g. binoculars, monoculars, and scopes. Granted there may be a load more, but since these are the 3 styles I'm planning on utilising, these are the ones I've learned stuff about.

I'm going to do this in a self created Questions and Answers session.

Q1. What the hell are optics?

Optics is the name given to items that allow your eyes to have enhanced vision. In the context we're using, it'll be focused on seeing a further distance. Technically glasses would count as optics, but that's not something I'm going to cover.

Q2. What the hell are those complicated number things about?

With optics you will get either 2 or 3 lots of numbers. The numbers will be in 1 of 2 formats. First, with 2 lots of numbers, it will look like this AxC. For example, 4x32. If it comes in a 3 group format, it will look like this A-BxC, for example 4-10x50.

The first number, or first 2 number groups (if it's a 3 lot of numbers) is the magnification. So, in the example above, it it's a 4x32, that means the optic has 4 times magnification. If it's a 3 lot of number, e.g. 4-10x50, the - sign means it's variable zoom. So the zoom can be from number A to number B. To use the earlier examples 4-10x50, it means variable zoom from 4 times magnification, all the way to 10 times magnification.

Now, time to explain the last number. The last number is simply the size of the lens on the front of the optic, in millimetres. By the front, I mean the part furthest from your eye and closest to what you're looking at. So, the above examples are talking about a 32mm and a 50mm front lens.

Q3. Why would you need different levels of zoom?

The amount of zoom required depends on what you're using the optics for. The more you zoom, the narrower your field of vision gets (this is a generalisation and not always 100% correction, but it's about 90% right). By this I mean the smaller the area you're able to see at any one time. So, if you're using a 4x optic or a 10x optic, the 10x optic will typically have a narrower field of vision. The field of vision is measured in degrees.

The second reason you'd want different levels of zoom, because you may well be looking different distances, or wanting a better view of the same distance object. There are all manner of different reasons.

Q4. Why is the size of the lens important?

The size of the lens can make or break an optic. The larger the lens, the wider the field of vision. More importantly, however, the more light that will enter the optic. This means that you'll get a much clearer picture in the day, but also at times when light levels are decreased, e.g. dusk or dawn. You can tell a late or early hunter, because they will have a huge lens on their scope.

So, if you use the example of a 4x32 against a 4x50, all things being equal, the 4x50 will give a clearer picture in the day, and will be more effective during the very early morning and later evening. The 4x32 will be lacking the light intake for the very early and very late hours, thus it's 'effective time' is much lower than the 4x50.

One last element about the importance of the size of the lens...weight. If you're a stickler for cutting weight, the optic with a smaller lens should weigh less, and thus you can make a pretty good weight saving by choosing an optic that fits the times you plan to use it in.

Q5. What is the best kind of optic to use?

This is a hugely varied question. I hate answering a question with another question, but the fact of the matter is, you need to be more specific. The best optic will depend entirely on what you're using it for. If you're off hunting, a good set of binoculars, with correct zoom and light intake, will be ideal for grid searching the landscape, then a spotting scope, with high variable zoom, and massive front lens, for getting a better ID on what you intend to shoot, and then a scope that has sufficient zoom and light intake, for your situation. Pretty complex hu? With practice, you'll refine your optics.

If you're just checking out a bird species to get enough data to ID the bird, a reasonable set of fixes zoom binoculars, or maybe even a monocular, would be sufficient. You don't need to pinpoint the exact details, but just pick out broad-stroked data points, for the recognition.

Q6. Do I need to spend a crap load of money? I've seen binoculars for over £600!

Well, this is where some people will go crazy at me, then others will agree with me and smile. So please...deal with my response and suck it up.

Yes and no, both at the same time.

I've used cheap crappy optics and been very unimpressed with them. I've also used cheap crappy optics and been pleasantly surprised. I've had some semi-expensive ones and preferred stuff I already had that were less than half the price of the semi-expensive ones. But the truth is, try out as many different types as you can, before you fork out any semi-large amounts of money.

When I first picked up a Swarovski scope, I wasn't too impressed...aside from the price tag on it. However, when I looked through it....DAMN!!! WOW!!! THAT MAKES SENSE!!! With companies like Swarovski and even Delta, they are able to charge a much higher premium, because their products are amazing! If you are able to afford this kind of optic, you will benefit from their greatness. Try one and you'll see what I mean.

Having just said that, could I justify spending £1000 on a scope? Not when the gun costs around £200, I can't. However, if the gun was closer to the £900 mark, and looking for 700 meter ranges, then I'd definitely be looking at a £1000ish scope. To do otherwise, would be to short-change your gun's abilities.

This is where the 'tight with money' crew get all up in arms and start crying bloody-murder. But the fact of the matter is, if you pick up a very high spec scope, and a cheap scope that have the same 'spec', the difference in quality should be screaming at you. If you can't see the difference, then you must honestly be blind, or the expensive optic is a fake. If the difference isn't screaming...buy the cheaper one...obviously.

It wasn't until I picked up a very-high end scope and looked through it, that I genuinely appreciated the VERY wide range of costing. It was one of those epiphany moments where you can't help but to say "Oh, I get it now."

But as I've already said, you do not need to go high on cost to get benefits from your optics. A simple monocular with a large front lens and a good magnification, can be pretty damn good and pretty damn cheap too.




I hope this information helps.

Enjoy.

The diameter of a fully dark-adapted, dilated pupil in a young adult of military age is about 7mm. The exit pupil of an optical system is determined by the unobstructed objective lens diameter, divided by its magnification, for example, for a standard "night glass" providing a exit pupil diameter of 7mm, a 4X rifle sight must have an unobstructed objective lens diameter of 4x7=28mm, a 6x sight 6x7=42mm, a standard Naval binocular 7x7=49mm, a night hunting scope 7x8=56mm.

If exit pupil is less than the fully dilated eye, the glass is still useful in daylight conditions where the iris of the eye is constricted, but a smaller exit pupil is less easily centered over the eyes, and is more apt to induce fatigue if the observer is standing on an unsteady support, such as the pitching deck of a ship, a moving vehicle or an aircraft in flight. For this reason, military optics are usually designed to provide an exit pupil of 7-8mm.

Brightness is determined not only by exit pupil diameter, but is also affected by light transmission losses through reflection. Anti-reflection coatings enhance brightness, but to be effective, ALL optical surfaces must be coated, not just the exterior surfsces you can see. Using Bundeswehr Zeiss 8x56 roof prism binoculars, I could readily identify feiend or foe symbols and read side numbers on tank turrets, which I was unable to do using an inferior 10x80mm gunsight, through smoke in evening nautical twilight. There is no substitute for quality. Check any prospective purchase for hoop or barrel distortion by counting bricks on a building across the street. Are the lines between masonry courses parallel? Are the blocks sharp, with parallel sides all the way to the extreme edges of the field of view?

Water tightness and resistance to fogging is tested in military optics by immersing completely under water, in bell jar, and pulling vacuum on the system, while watching for bubbles. Anti-fog properties are conveyed by proper sealing of the system. Nothing more than dry air in the clean room where te optics are assembled is needed. Evacuating systems and filling them with dry nitrogen is mostly advertising hype, for if the system is not sealed the nitrogen will leak out and be displaced by ambient air.

More important than magnification is resolution. Resolving power is determined by counting line pairs on a standard NATO resolution test target. I was able no

Great info CH.

A bit more tech than I was hoping to go in an Intro to Optics thread, to make it a little simpler to understand haha, but still really appreciated stuff!

Love the brick test. Never heard that before. In the local hunting store I go to, I like to read price labels from the other side of the warehouse/shop. If I can do that, I know I'm on to a good optic.

Also the right tool for the right job is critical

i use a Hawke scope on my air rifle with the air rifle specific "Map 6" reticle, it certainly helps get a clean kill if you can judge the distance right

The difference in price and quality on optic's is astounding and until you've used one end of the sprectum back to back with the other end you would never believe the difference , i would love high end optic's but i don't have pockets deep enough......like buying Hifi as you head up the rrp's the difference in quality is hard to justify...and sometimes on rare occasions a product bucks the trend and is quite fantasic at a really good price.....scopes go from £30 to 3 or 4k.....my budget for what i consider good performance for a not too terrifying price is £400-£700 pounds but i will say i'm quite a traditionalist , not into mil dot or any other fancy reticles i like fixed mag for its simplicity and robustness but that just me...i've never had a pair of bino's that cost more than £150 but i do appreciate that the much dearer ones work closer to dusk and dawn than mine do but again i don't have deep enough pockets.

(14 April 2014, 14:14)Midnitemo Wrote: [ -> ]i don't have deep enough pockets.

I think most people are in that position.

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For me, the question is, will the cheaper optic do the job that I need it to, and will it be robust enough to last?

If the answer is yes, then that's cool. Go with the cheaper one.

just don't get a £5 scope from ebay like a chum of mine did,

similar size to a packet of smarties, though i think the smarties tube may have out performed this scope lol

I've got a 3-9x50 air rifle scope, its touted as a wide view angle, i'd certainly agree with that.

What are the benefits of binoculars over scopes? I'm one eye dominant so have only ever bought scopes. Aren't binoculars just twice as heavy and bulky?

Vision can be regulated for a dominant eye , bino's can be adjusted for focus whist the other side is fixed at the eyepiece.....bino's are not so tiring to use gather more light so can be used deeper into the dusk earler before the dawn , wider field of view , you don't terrify people by pointing guns at them to look through the scope(really bad practice)....yes they are heavy but worthwhile , if you break / wear out your scope your going to have probs , having bino's means somebody can spot for you , handy when fighting they can be finding you're next target for you as you are dealing with the irst one.

(14 April 2014, 16:48)SlyUrbanFox Wrote: [ -> ]What are the benefits of binoculars over scopes? I'm one eye dominant so have only ever bought scopes. Aren't binoculars just twice as heavy and bulky?

That's a very fair question. The simple answer is, binoculars are a damn sight (no pun intended) easier to use than scopes. As humans, we need 2 eyes to give better depth perception. The same is true with optics. Granted a scope is used with one eye, but we estimate distance with both eyes open then adjust the scope accordingly. We don't see an object, then suddenly cover one eye to estimate the distance as well as we can. If we have a scope, and we are unsure of the distance to the object, we look up then check with both eyes open. Better depth perception.

Another thing, as I said binoculars are easier to use, but I did not really go into why. Well, they are easier to hold steady, easier to hold up on 'target' and adjust the focus. Oh, and they can be used to account for the weakness or strength of certain eyes. I am hugely left eye dominant, but I'm right handed...so have a slight issue with using scopes (easily rectified with practice and a lot of patience...those whom have seen me should really wouldn't know I was using the scope on my weak eye). However, when I use binocs, I am able to account for my right eye weakness, and adjust the binocs accordingly. This allows me to get brilliant vision over the distance. Much better than had I used a monocular or a scope...even if it was used with my dominant eye.