True or False?
by Matt Dubber
Once upon a time, we lived in a much simpler world where there weren’t many options to choose from in terms of optics, and everything looked pretty much the same. However, with the introduction of new niche shooting sports and the rise of competition between manufacturers, we are now flooded with a vast array of different optics designs and are constantly bombarded from all sides with marketing blabber telling us why Product A is superior to Product B. Of course some of this is true, but unfortunately, much of the information we learn can too easily be passed from person to person without being verified, and the result is a massive number of people who believe something just because it sounds sensible. Let’s run through some of the common misconceptions floating around and explain why things may not be as clear-cut as you think.
1) A larger Body Tube increases Light Transmission
This is probably the biggest piece of false information that I’ve seen floating around, and is the most important to address, because there seems to be a craze about 34mm tubes at the moment and I think many people don’t even know why!
Light transmission is a factor of a number of things. When light enters the scope, it does so through the objective lens, which then focuses the light into the erector system, where it passes through a series of lens elements before leaving the scope through the ocular lenses. The optical design can largely dictate how much light is lost (scattered or reflected back) while passing through the riflescope. A larger objective lens helps to focus more light into the erector system, and therefore scopes with larger objective lenses often seem brighter to the eye.
I say normally, because this is not always the case. Optical systems can vary greatly from fixed-magnification to crazy 7x or 8x systems (like a 2.5-20x) which have more complicated optical systems with more lens elements. Each lens in an optical system is coated with anti-reflective layers which aid light transmission, and naturally the more lenses there are, the greater the collective loss of light can be. These lens coatings can be incredibly technical, because they need to aid transmission of all visible light in a balanced way - Done incorrectly, the image can come out the other side looking very unnatural, perhaps with a strange tint or bizarre colour temperature.
A great example of how the quality of lens coatings can affect light transmission can be seen when comparing the Helix and the Nexus. On paper, the Nexus is extremely similar to the Helix - Both have a 30mm tube, a 50mm objective, 4x zoom (6-24, 5-20) and comparable length.
However, one of the things you pay for on the Nexus is superior glass quality. The Nexus is Advanced Fully Multi-Coated, which means that each lens element has 5 layers of anti-reflective coatings which reflect less than 0.3% of light each. This is excluding the hydrophobic antifouling layers which are applied to the ocular and objective lens surfaces. Added together, the total light transmission of the Nexus is 91.3%.
Graph showing the light transmission through the entire Nexus 5-20x50 optical system. Visible light lies in the wavelengths of 420 to 700nm
The Titan is a great middle ground between the Helix and the Nexus. While the Nexus achieves brilliant optical clarity and light transmission through ultra-high quality components, the Titan does so with the use of 8 coatings per lens, plus 5 pieces of Lanthanide glass which add weight, but help to achieve this next level of optical quality without breaking the bank.
It should also be noted that with age, your eyes can deteriorate and become less capable of capturing all available light. At 30-40 years old, your pupils are not able to dilate as much as a 10 year old’s, and depending on the exit pupil diameter of the riflescope, you may perceive the image as darker even though it may not be.
Light Reflection graphs for lens elements in the Helix 6-24x50 (left) and the Nexus 5-20x50 (right). Here we can see the superior performance of the Nexus lenses.
So… what does a larger body tube actually do? Well, put simply, it creates more space for the erector tube. The erector tube is the part that houses the reticle and moves when you turn the turrets. It is held in place by the turrets at the top and on the right, while a spring holds pressure against it in the opposite direction. More space around the erector tube means that the tube can be deflected further, resulting in greater elevation and windage travel. This is why most extreme long range shooters will opt for a 34mm or 40mm tube scope.
The other thing that can happen is that the designer of the scope may decide that optical features are more important than turret travel, and actually increase the overall diameter of the erector tube as well. This can help increase the field of view. But keep in mind that these features come at the cost of additional weight, and if you don’t need a huge amount of internal adjustment, you may prefer to opt for the 30mm alternatives. In terms of optical quality, there really is no difference!
2) A Larger Objective lens creates a Brighter Image
Well, this is not entirely true. If you hold a 1-6x with a 24mm objective lens next to a 8-32x with a 56mm objective lens, you may not even notice any difference in brightness. This is because the objective lens is designed in combination with the desired magnification to create a specific exit pupil diameter (the disc of light that reaches your eye when you look through a scope).
So objective lens diameter is key for light transmission - However, you shouldn’t make the mistake of comparing a 3-12x44 with a 6-24x50 and simply concluding that the 6-24x50 is superior because it has a larger objective lens. Make sense?
It’s also important to circle back here and remind you that there are many factors that affect light transmission and apparent brightness - Having a large objective lens doesn’t automatically mean the scope will be bright. If the light is scattered, absorbed or reflected badly before reaching your eye, your large objective counts for nothing!
Sunglasses don't help with light transmission either!
3) Longer Scopes have Better Optical Quality
Well, this can be true, but not always. what needs to be considered here is that light inside a scope needs to be bent multiple times. That’s what lenses are for, right? Well, what does a long scope have in its favor? If you think about it, the light that passes through the objective lens is focused into the ocular tube. Compact scopes have to be incredibly well-engineered with high-quality lenses and tight tolerances because the light has to be bent at a more extreme angle. Longer scopes have the advantage of being more forgiving - The light does not have to be bent at such extreme angles, and therefore there is more room for error. However, this doesn’t always make them better.
A well-engineered scope with high-quality components like the Nexus can get away with a compact design because the lenses are built and installed to such high tolerances. The result is a clear optical system that is also light and compact. This is partly why we are happy to build the Helix and Titan models at reasonable lengths. We feel that building them any shorter may compromise on image quality. Compact designs are better kept for low-magnification scopes, or very expensive & precise ones!
We forget that compact is not always important. Trekking up a mountain on a hunt? Sure! But benchrest shooters, for example, are very happy to use long, heavy optics. And generally, these optical systems are very clear at a very affordable price. It is less likely for a small alignment error to affect a long scope than it is to affect a compact one. Element Optics has not built a dedicated Benchrest scope yet, but if we get around to it, these are the sort of factors we will take into account!
4) I need more magnification to shoot long range.
I remember competing at a 100yd benchrest event with a fixed 16x riflescope a few years back and not feeling at all disadvantaged because the glass was crystal clear - far clearer than some other high magnification scopes on the benches around me. Despite the lack of high magnification, I could see the target rings clearly and others couldn’t! When you zoom a scope in, you are not only magnifying your sight picture, you are also magnifying the optical imperfections of the scope. If you see some chromatic aberration, fringing and other artifacts at 10x, it will probably look worse when you zoom in.
We have tried to stay away from crazy zoom specs, particularly on our cheaper models. Trying to create a budget scope with a 7x or 8x zoom is asking for trouble. You may have the luxury of having greater zoom at your disposal, but it will come at the expense of optical quality. It’s for this reason that we have chosen the relatively mild 4x zoom (6-24x50 Helix) and 5x zoom (5-25x56 Titan) for our low and mid-range optical systems. We feel that pushing it any further is not actually beneficial. You can get away with budget, high magnification scopes if the magnification is fixed, which is why many benchrest shooters tend to like using fixed 32x or 36x scopes. The reason this works is that there are fewer lenses in the assembly - which in turn means that there is less collective error (better optical quality) and less expense (cost can be distributed across fewer components, therefore there is no need to skimp on quality).
The decision to limit the Nexus to a 5-20x was not actually due to concerns over optical clarity, but rather reticle thickness - It is difficult to create a First Focal Plane reticle that is useable at a large range of magnifications. If or when we create a high-magnification scope, we will likely use a high-quality optical system to ensure that the image doesn’t deteriorate at higher magnifications.
5) Heavier scopes are more durable
If you’re planning on throwing your scope off a cliff, then perhaps a thicker body tube may help! However, thinner body tubes tend to absorb shockwaves and vibrations better instead of transmitting them. Sometimes, thicker is not better. If your scope does break, it will likely have nothing to do with the thickness of components. Normally the most vulnerable parts are those that are made to move inside the scope itself, like the erector system. These moving parts can wear out with time or wiggle loose if not fixed in place correctly, and therefore it is important that the correct adhesives, correct tolerances and correct materials are used.
The Helix and Titan are built with 2mm thick body tubes, which are actually thicker than the Nexus tube. We did this simply because cheaper mounts and incorrect torque specs can badly damage body tubes.
Normally, people that drop $1500 on a scope will also purchase higher-quality rings that are the right shape and come with reasonable torque specs. But often, customers looking for a budget setup also want cheaper rings, and cheaper rings that don’t align properly or have inconsistent shapes can badly crimp & deform body tubes, misaligning lenses or crushing internal components.
It is important to use quality mounts and correct torque specs.
We highly recommend that you stick to a torque spec of 15-18 in-lbs when tightening rings, and to ensure that all ring surfaces are flush, especially when using adjustable rings. Adjustable rings or cheap, misaligned rings are the biggest cause of damaged scopes that are reported to us. You can find our mounting instructional video and other resources on our video page.
Hopefully, this has been helpful to those looking to purchase a new scope! If you’re ever in doubt, feel free to contact us at email@example.com or through social media - We’ll be more than happy to answer your questions!