Last month, I began a series on rifle sights as an introduction to which sights might best suit your rifle’s purpose. The first article covered iron sights. This post continues the subject, focusing now on telescopic sights
. Telescopic sights, commonly referred to as “scopes,” use a system of lenses to magnify the appearance of a target from a distance. Not surprisingly, this magnification effect on the user’s field of vision is beneficial for styles of shooting that require precision from a distance. While distance shots, to some degree, are capable with mere iron sights, adding a scope reduces some of the challenge involved.
How They Work
Telescopic sights generally have a combination of curved lenses and reflective surfaces within metal sleeve. The shooter looks through the ocular lens (smaller, and of lower magnification), and the objective lens at the scope’s far end increases magnification. Some telescopic sights are fixed in the amount of magnification they can provide. Others are variable. The “power” of the magnification of any particular scope is usually denoted like so: optical magnification x obejctive lens diameter (for fixed magnification optics), or minimum magnification – maximum magnification x objective lens diameter. For example, the Leupold scope shown below is denoted 2-12×42. Which means the lowest magnification is 2x larger than naked eye, minimum, with a maximum of 12x, and the objective lens is 42mm in diameter (lenses are often measured in metrics, rather than the US customary units).
Lens Features
Having a larger objective lens diameter is a benefit as well as a disadvantage. The larger the objective lens, the more light can enter through the end of the telescopic sight. More light provides a brighter image. However, having a large optic means the profile is larger. If one wishes to put their rifle through heavy use, the delicate glass within their optic may not survive potential impacts. And, the more glass on the scope’s end, the more surface there is to try to keep clean and free from scratches – both of which could impede vision through the implement temporarily or permanently. However, if one is gentle enough with their scope use and storage, these issues can be avoided.
Another notable feature of telescopic sights which could contribute to whether or not they suit your rifle’s purpose is the visual phenomenon of field of vision that is necessarily altered. The magnification that telescopic sights provide is limited to the expanse of the lens. Therefore, an additional benefit to having a scope with a wide objective lens allows for a larger field of view when looking down the scope. When one is shooting from a fixed vantage, or other position that requires little movement, having a limited field of view is not as significant of a detriment as to those who may wish to change shooting location frequently in one sitting, or for someone who wishes to shoot while on the move.
Configuration Options
There is a vast range of telescopic sights available, not only with varying levels of magnification and lens diameter, but also differing coatings for the glass (both to protect the glass itself, and to alter the way the light enters the optic, which could improve clarity and color, levels of adjustment for windage and elevation, and there are even some scopes that include electronic elements
that assist in ballistics calculations. There is also a wide array of reticles of varying sight pictures and materials (many are made of thin wire located on the first focal plane within the scope, while others are etched glass plates fixed in the same location).
If shooting from a fixed position with a need for precise shots aimed at a distant target, the quality of the telescopic optics one uses could be as important, if not more important, than the rifle upon which the scope is mounted. However, if your rifle is better suited to close quarter combat, or short range target engagements, a reflector or reflex sight may be a better bet for your shooting experience. The next article in this series will introduce the benefits and downsides of that style of optics, so stay tuned for Part 3.
An excellent summary.
NateGranzow Thanks :] I found the more I learned about optics, the harder it was to summarize everything… there are so many options. It can be a bit overwhelming.
FateofDestinee I can imagine. Not a narrow topic!
A well tuned in scope is hard to beat, red dots and iron sights are okay up close for fast acquisition, but for accuracy and longer distances a scope is the way to go. Another advantage is they don’t need batteries.
peter3101 True story.
Looking forward to part 3 !
ksdad2two Me too, actually haha I love writing about this stuff. I’m lucky to have an outlet for it. I bore my mother to tears if I just talk about it.
Another disadvantage of large front lenses is that a great amount of light will fatigue your eyse more than a smaller amount out of a smaller lense. This is an issue in shooting sports and activities that require to stay on scope for long periodes of time. Larger lensen are useful when shooting in low light condition, for example hunting at twighlight (not the movie, even if i think many of us fancy to lol).
Scope’s tube diameter is also a factor that determinate the amount of light trasmitted and the field of view, as well as the amount of sight adjustments excursion.
AlessioBaldi Excellent points, all. Thanks for the feedback!
ThAnk you too Des. Those are the first things that came to mind. Despite you have made a good summary, you just opened pandora’s box xD.
I spent many time studying about optics an looking trough them. It has been my main shooting activity for years. If you want to know more about omthem fell free to ask 😉
*feel… you din’t have to free falling lol
Just a note on low light capability: the amount of light that reach the shooter eye is dictated by the ratio between front lense diameter and magnification. The index of how many light reach your eye is called exit pupil, wich is obtained deviding the front lense diameter per the number of magnification. Thus a 6×40 has, for example, an exit pupil of 40/6=6.6mm. From here you can see how smaller magnifications allow more light trasmission.
But there is another thing to consider, your pupil diameter. If you have a pupil diameter of 5mm you can receive only the light that pass trough a 5mm exit pupil. Thus higher lense diameter and highexit pupil are often useless. Your pupil diameter decrese with age due to elasticity, so take this in consideration when choseing an optic.
Thanks for the additional input ;]
AlessioBaldi You are forgetting that a pupil opens and closes depending on light conditions.
I know. But exit pupil and pupil diameter are a concern when you shoot in low light condition, thus when your pupil is dilated.
…….still waiting for part 3 ! ……
ksdad2two I’ll get there, I promise!
I see articles all of the time on the latest EOTech or Red Dot sight or ACOG sight or Trijicon sight. Those are all very nice sights. Expensive ones too. How about an article on the cheaper, not gonna break the bank, sights? Ultra cheap under a $100 but still a somewhat decent quality optic. Cheap between $100 and $150. And then still affordable but starting to get up there in range with the big boys, $150-$200. How about an article on handgun scopes? Money is tight for some of us.
Wysiwyg101 These guys are new but Hal Swigget did articles on handgun scopes that were inexpensive almost 30 years ago…..I remember he liked Millet Scope Rings because they were much stronger and unless the handgun was a Thompson Center a 3 power scope was max and a I recall he prefered Dan Wesson 44 magnums and 45 Casuls. I would not want to put a $100 scope on my Smith & Wesson 624 because the scope would not handle the recoil. MyIvar Johnson Cattleman 44 Magnum needs no scope at 100 yards due to the fact that it has an 18 inch barrel.
Wysiwyg101 These guys are new but Hal Swigget did articles on handgun scopes that were inexpensive almost 30 years ago…..I remember he liked Millet Scope Rings because they were much stronger and unless the handgun was a Thompson Center a 3 power scope was max and a I recall he prefered Dan Wesson 44 magnums and 45 Casuls. I would not want to put a $100 scope on my Smith & Wesson 624 because the scope would not handle the recoil. MyIvar Johnson Cattleman 44 Magnum needs no scope at 100 yards due to the fact that it has an 18 inch barrel.
hartcreek Wysiwyg101 Sounds like a decent starting point. However, scopes as well as prices have changed over the years. Hoping maybe these folks can come up with something a bit more modern (and still cheap…lol). My handgun that needs a decent scope is a Beretta Neos U22. .22lr in caliber. At this point I can only dream about owning one of the guns you mentioned. Thx for replying to my query. Take care and stay safe.
Wysiwyg101 hartcreek hmm irackvetran8888 did what you probably need last month……he showed how to replace standard dots with them that glow in the dark. It is a two part epoxy……I did a bunch of my guns with it and if you cant afford the glow stuff you can use white fingernail polish.
Wysiwyg101 iraquevetran 8888 dis a video in the last month about site upgrading. He was adding Tricon to something which I have done and I had the set up it takes a catalyst. I did many of my sites with it BUT you can do the same with white nail polish
I see articles all of the time on the latest EOTech or Red Dot sight or ACOG sight or Trijicon sight. Those are all very nice sights. Expensive ones too. How about an article on the cheaper, not gonna break the bank, sights? Ultra cheap under a $100 but still a somewhat decent quality optic. Cheap between $100 and $150. And then still affordable but starting to get up there in range with the big boys, $150-$200. How about an article on handgun scopes? Money is tight for some of us.
I prefer a scope on most of my rifles; I like the Nikon optics as a good balance between IQ and price. For longer range shooting- I prefer the Predator BDC sights of the Coyote Special- the center is a circle- which allows you to see your target at longer distances rather than have the crosshairs obfuscate the center… Eye-relief is something else to consider; worth paying a bit more to have a decent amount ( 3 to 4 inches ).
For those wanting night sights but can’t or don’t want to afford them- consider this: You can paint them with a glow in the dark paint like Glow-On, cover it with nail polish- and hit it with a bright light when you need them- for a fraction of the cost. Second thing to consider; night sights are not the end-all-be-all. Generally- if it’s dark enough to need night-sights- you probably need a GOOD flashlight because you can’t clearly identify your target otherwise. Additionally- the actual amount of time a night sight is useful by itself is perhaps 20 minutes out of the day! It’s stuff people need to be real about; consider what, when, how…
I had a conversation with someone at work- he does not need a flashlight- cause his house is lightly lit all day long; I asked him about that 10 day power outage we had a few years back when tornadoes came thru the area.. I think he’s considering a good flashlight now. Yes, I also mentioned that where he keeps his gun- is where he needs to keep a good working flashlight.