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January 10th, 2023
For many years, the Swarovski Optik website featured a blog with interesting technical articles. (Unfortunately some of these articles have been taken offline.) In the “On Target” series of blog stories, Swarovski provided a handy explanation of how optics systems work, with exploded diagrams of rifle scopes, spotting scopes, and binoculars. We’ve reproduced the key diagrams here. CLICK HERE for Swarovski On Target Archive.
Scope Terminology
Focusing Lens
The focusing lens is an adjustable lens inside the optical system for focusing the image at different distances…. In the case of rifle scopes, apart from focusing, the focusing lens also facilitates parallax compensation.
Objective Lens
The objective lens is the optical system’s front lens group facing the object and operates like a converging lens. Its purpose is to display an image which, at the image plane, appears upside down, laterally transposed and reduced, and which is subsequently displayed correctly again by the reversal system.
Diopter Adjustment
For rifle scopes, the reticle can be focused using the diopter adjustment on the eyepiece, thereby correcting any visual impairment. [Editor’s Note: Movable eyepiece diopter adjustment is not offered on all rifle scopes. It is a useful feature on Swarovski and other premium scopes. This allows shooters who need eyeglasses to get a sharply focus image even without wearing corrective lenses. Of course shooters should always wear ANSI-certified eye protection. With the diopter, folks who need correction can use inexpensive, non-Rx safety eyewear instead of expensive prescription safety glasses.]
Reversal System
The purpose of the reversal system is to reverse the image by means of prisms in binoculars and telescopes, and lenses in rifle scopes….The lens reversal system is needed in rifle scopes to control the variable magnification and move the exit pupil[.]
Resource tip by EdLongRange. We welcome reader submissions.
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June 2nd, 2017
Those of us over-50 types can use some help when shooting iron sights. As one gets older, your eyes lose the ability to rapidly adjust to different points of focus. In practice, when shooting a rifle, this means the target image may be sharp but the sights are blurry, or vice-versa. Or you may be able to see the target and front sight reasonably well, but the rear sight is a complete blur. (That is this Editor’s problem when shooting a rifle, such as a Swedish Mauser, with a notched blade rear sight.) Even if you are using a rear peep sight, you may see a blurry rear circle (or two circles if you have astigmatism). Placing a diopter sight (sighting disc) on your shooting glasses can help many people see open sights better, when shooting both handguns and rifles.
 Merit Corp. in Schenectady, NY, offers an adjustable optical disc that attaches to shooting glasses with a rubber cup. Though primarily intended for pistol shooters, the Merit optical attachment can also be helpful when shooting rifles with open sights, such as military bolt actions. Priced at $65.00, the Merit device features a shutter-style, adjustable aperture iris.
 Merit explains: “The human eye, whether or not prescription glasses are required, cannot focus on both sights and the target at the same time. The eye will constantly shift focus from the sights to the target trying to ensure proper alignment. Unfortunately, as we age, the eye loses the flexibility which allows it to do this; thus, sights and target begin to grow fuzzy. There is a simple way to combat this by increasing your eyes’ depth of field (range of focus). If you look through an aperture or pinhole of the correct size, you will be able to see both sights clearly, and the target will be clearly defined as well.”
In addition to optical attachments for eyeglasses, Merit produces a variety of adjustable iris sight products for rifles, including the Variable Iris Aperature for AR15s. Visit MeritCorporation.com or call (518) 346-1420.
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July 18th, 2015
The Swarovski Optik website features a blog with interesting technical articles. In the “On Target” series of blog stories, Swarovski has provided a handy explanation of how optics systems work, with exploded diagrams of rifle scopes, spotting scopes, and binoculars. CLICK HERE for Swarovski Optics Blog.
Scope Terminology
Focusing Lens
The focusing lens is an adjustable lens inside the optical system for focusing the image at different distances…. In the case of rifle scopes, apart from focusing, the focusing lens also facilitates parallax compensation.
Diopter Adjustment
For rifle scopes, the reticle can be focused using the diopter adjustment on the eyepiece, thereby correcting any visual impairment. [Editor’s Note: Movable eyepiece diopter adjustment is not offered on all rifle scopes. It is a useful feature on Swarovski and other premium scopes. This allows shooters who need eyeglasses to get a sharply focus image even without wearing corrective lenses. Of course shooters should always wear ANSI-certified eye protection. With the diopter, folks who need correction can use inexpensive, non-Rx safety eyewear instead of expensive prescription safety glasses.]
Reversal System
The purpose of the reversal system is to reverse the image by means of prisms in binoculars and telescopes, and lenses in rifle scopes….The lens reversal system is needed in rifle scopes to control the variable magnification and move the exit pupil[.]
Resource tip by EdLongRange. We welcome reader submissions.
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January 14th, 2014
It’s official. No more “vaporware”. In 2014, Leupold will sell a 7-42x56mm VX-6 scope for approximately $1800.00. This scope will be “coming out this summer”. This is a very impressive optic that will give other premium high-magnification competition scopes a run for their money. The new 7-42 features a 34mm main tube. That large diameter tube helps the scope deliver an estimated 70 minutes of elevation (final specs subject to change). There is a side parallax control, and target turrets with 1/8th-MOA click values and built-in zero stop. We were pleased to see that the scope features a “fast-focus” eyepiece with plus/minus diopter adjustment. Initially the scope will be offered with two (2) reticles, the TMOA and TMOA Plus. These feature MOA-based hash marks, with a small gap in the very center with a target dot at the aiming point.
We did get a chance to test the scope. Jason successful engaged targets at 960 yards using a .308 Win Colt modular rifle fitted with the new 7-42x56mm Leupold. Jason reports that the clicks are tactile and positive. The scope is sharp and bright all the way out to the edges of the viewing circle, even at max 42 power. We liked this optic, and can’t wait to get our hands on a final production version.
Leupold 7-42x56mm VX-6 ($1800.00 MSRP, mid-2014 release)
- Magnification Range: 7X to 42X
- Front Objective: 56mm
- Elevation Range: 70 MOA (estimated) with Zero Stop
- Main Tube Diameter: 34mm
- Warranty: Full lifetime Leupold Gold Ring Warranty
Watch Video Showing Features of Leupold 7-42x56mm VX-6 Riflescope
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July 3rd, 2012
Those of us over-40 types can use some help when shooting iron sights. As one gets older, your eyes lose the ability to rapidly adjust to different points of focus. In practice, when shooting a rifle, this means the target image may be sharp but the sights are blurry, or vice-versa. Or you may be able to see the target and front sight reasonably well, but the rear sight is a complete blurr. (That is this Editor’s problem when shooting a rifle, such as a Swedish Mauser, with a notched blade rear sight.) Even if you are using a rear peep sight, you may see a blurry rear circle (or two circles if you have astigmatism). Placing a diopter on your shooting glasses can help many people see open sights better, when shooting both handguns and rifles.
Merit Corp. in Schenectady, NY, offers an adjustable metal diopter that attaches to shooting glasses with a rubber cup. Though primarily intended for pistol shooters, the Merit diopter can also be helpful when shooting rifles with open sights, such as military bolt actions. Priced at $65.00, the Merit device features a shutter-style adjustable aperture iris.
Merit explains: “The human eye, whether or not prescription glasses are required, cannot focus on both sights and the target at the same time. The eye will constantly shift focus from the sights to the target trying to ensure proper alignment. Unfortunately, as we age, the eye loses the flexibility which allows it to do this; thus, sights and target begin to grow fuzzy. There is a simple way to combat this by increasing your eyes’ depth of field (range of focus). If you look through an aperture or pinhole of the correct size, you will be able to see both sights clearly, and the target will be clearly defined as well.”
In addition to diopters for eyeglasses, Merit produces a variety of adjustable iris sight products for rifles, including the Variable Iris Aperature for AR15s. Visit MeritCorporation.com or call (518) 346-1420.
Cheaper Diopter from Lyman
If you can’t afford a Merit adjustable diopter, Lyman offers a similar all-plastic device for under $20.00. The Lyman Hawkeye Shooting Aid mounts directly to your eyeglass lens with a rubber suction cup. The diopter section is made of plastic, and aperture diameter is non-adjustable.
Though it is simple and inexpensive, the Lyman Hawkeye works for many shooters, if positioned properly. (Don’t think this is anything close to the Merit Diopter in quality though!) Currently, Cabelas.com has the Lyman Hawkeye on sale for just $12.88, item # IK-229094. MidwayUSA sells the Lyman Hawkeye for $18.99, item # 936878. One MidwayUSA customer reports:
“This thing really works! I have it on my shooting glasses, and it has made a significant improvement in my ability to keep the front sight and target in focus at the same time. If you are older and find that you are having a hard time keeping the target in focus over ‘iron sights’, then this may be the answer to your problem. Mine works equally well for both pistol and rifle, although I do have to change the device’s position on my shooting glasses when changing weapon types.”
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December 12th, 2009
Texas discount vendor CDNN Investments has released its latest 2009-5 catalog (30 mb PDF file). As usual, the catalog features big discounts on handguns, rifles, and shotguns. Among the many bargains, we spotted two exceptional deals in the latest CDNN catalog….
 Half-Price Kahles Hunting Scopes
CDNN acquired a selection of 1″-tube Kahles Helia CL hunting scopes and is selling them at liquidation prices. Kahles is a highly respected Austrian optics-maker. We wouldn’t say that Kahles is on a par with Swarovski or Schmidt & Bender, but Kahles scopes are very high quality, with excellent glass, etched reticles (no reticle wires to drift or break), wide field of view, +2/-3.5 diopter eyepiece, and very good fit and finish. If you’re looking for a quality 3-9 or 4-12 hunting scope, here’s a chance to own a premium European scope for a “below wholesale” price.
CLICK HERE for CDNN KAHLES Scope Sale Order Page.
 Uncle Mike’s Holster for $9.99
CDNN is selling the Uncle Mike’s straight drop belt holster for half price — just $9.99. Models are available for popular Beretta, Glock, HK, Ruger, S&W, SIG, Springfield, and Walther pistols. The holster is made from injection-molded Kydex. Injection molding allows for a MUCH more precise fit than the typical folded-over Kydex holster. This editor has used this injection-molded Uncle Mike’s holster for my Glocks and HKs, and the fit is excellent. The handgun is secure but the draw is easy. Injection-molding allows nice straight corners, so the plastic doesn’t bind or grab as with many “hand-made” Kydex holsters. If you want an “on the belt” holster, I highly recommend this model. You may be surprised to see how much better it works than holsters costing 5 or 10 times as much.
Don’t be put off by the low price. This editor owns and uses Uncle Mike’s injection molded holsters for various handguns. I consider this the best outside-belt holster I’ve ever tried. It is clearly superior to a $85 Blade-Tech Kydex I had for an HK USP, and, I have to admit, it works better than the pretty $125 Milt Sparks leather holster I had custom-made for a 1911. The straight-drop is ideal for range use, and in a vehicle you can wear it on the left-side as a cross-draw (CCW permit required). These holsters fit close to your belt and all metal fittings are recessed or covered so they don’t scratch your gun. IMPORTANT: All plastic/Kydex holsters will cause some wear on high-gloss blued finishes. If your pistol is high-gloss blued, I suggest a soft leather holster instead.
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