I bought a Guns and Ammo magazine for a friend who was in the hospital and sent it to them. I took a picture of this article I wanted to hunt down and read later but I cannot find it anywhere. Does any one know where i can find this article? Its by Tom Beckstrand.
- Thread starter Texaslongshot
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Closest I could find in G&A online:
www.gunsandammo.com
Latest issue teaser in online, too, but don't see the Beckstrand article.
The Anatomy of a Scope - Guns and Ammo
Ever wonder what is going on inside a scope. Here is what is going on and how it affects you.
www.gunsandammo.com
Latest issue teaser in online, too, but don't see the Beckstrand article.
If true astronomical observatorys would have one inch objective lenses.
If I cut the two front legs off a cheetah, he don’t run so fast no more.
Do bigger objectives make you loose your calipers because I can’t find mine.
My guess is the article is a "play on words" because if they actually think they can prove that larger objective lenses do not gather more light then they're going to have a boatload of optical engineers raising their hands in objection.
Wasn't this settled in the 1660's?
Hi,
Well I am pretty sure the Author of the article is a member here.
Retired Major @tbeckstrand
Sincerely,
Theis
Well I am pretty sure the Author of the article is a member here.
Retired Major @tbeckstrand
Sincerely,
Theis
Several have posted that this is a dead horse and almost silly to ask the question as its been settled. I would still like to read his article.
Regardless, Could someone help me quantify then?
Take a nightforce 4-16x42 or a 4-16x50 same class same coatings. How much more "light gathering am i getting from an extra 8mm of objective lens diameter?
Regardless, Could someone help me quantify then?
Take a nightforce 4-16x42 or a 4-16x50 same class same coatings. How much more "light gathering am i getting from an extra 8mm of objective lens diameter?
Probably written by a guy with a small objective.....I did a similar paper on penises (peni?).
Bigger objectives usually result in bigger achievements.
I am guessing the gist is going to be something like, "With the new coatings that Zeiss/Leica/Swaro just put on the XYZ scope you get 95% light transmission, so a 40mm objective gives you more light transmission than the 42mm objective lens on the 1974 Tasco ABC lens that only had 78% light transmission."
But I like optics articles and Tom Beckstrand, so I'll read it when I get a chance.
But I like optics articles and Tom Beckstrand, so I'll read it when I get a chance.
I've always heard the reason the PVS 27 had that huge objective lens was to look badass, not gather more ambient light.
Lol
Also, if you mount your scope backwards then the power ring is incorrect.... you have the biggest image on low power and then magnification decreases as you turn it up. "What the hell does this have to do with anything?" you may ask. Absolutely nothing.... but this felt like the perfect place to share that.
Also- scopes do gather more light with a bigger objective if they have a MOA reticle. But MIL scopes do not have this same design because of the manufacturing process. Reason #5 that MOA is superior.
Also- scopes do gather more light with a bigger objective if they have a MOA reticle. But MIL scopes do not have this same design because of the manufacturing process. Reason #5 that MOA is superior.
I believe physics says you can’t “gather” light...well, unless you are a black hole.
photons travel in a line unless influenced by VERY strong gravitational fields from very massive astronomical bodies (think gravitational lensing)
my half formed understanding is that a larger objective has more surface area than a smaller one and hence more photons striking it, right?
now, if both the larger and smaller objective are both ground to the same focal distance, at that focus there will be more photons from the larger lens so it will be brighter.
I’m more than willing to be proved wrong about all of this.
photons travel in a line unless influenced by VERY strong gravitational fields from very massive astronomical bodies (think gravitational lensing)
my half formed understanding is that a larger objective has more surface area than a smaller one and hence more photons striking it, right?
now, if both the larger and smaller objective are both ground to the same focal distance, at that focus there will be more photons from the larger lens so it will be brighter.
I’m more than willing to be proved wrong about all of this.
Guns & Ammo. Now that is a true treasure trove of solid data.
@THEIS - Thanks for the tag, or whatever it's called. It's nice to know when something I've said has drawn the Hide's interest.
The cliff notes version of the article is the optics-buying community obsesses way too much over size of the objective lens and fails to account for the effect of the erector assembly has on the amount of light passing through a scope. Yes, a larger lens lets more light pass into the scope; however, both the objective lens and the erector assembly determine the size of the exit pupil and the exit pupil is what really determines how much light makes it to your eye. It is also harder to build a larger objective lens correctly, so it costs more (this is why you should never buy cheap scopes with large objective lenses). A larger objective lens is also harder to immobilize from impacts scopes that get used will take (again, don't buy cheap scopes with big objective lenses). A poorly constructed large objective lens will let more light into a scope and yield a bright blurry image, which I find offensive.
I wrote that article because I'm tired of seeing good people feel obligated to buy a more expensive scope, just because the objective lens is bigger and "it gathers more light." I'm also tired of seeing optics manufacturers feel pressured to build scopes with massive objective lenses knowing that the image quality will take a hit (unless they jack up the price, which they don't want to do) and that the bigger lens will move more under impact, yielding point of impact shifts unless additional money is spent to immobilize it.
If you're buying anything from Nightforce, anything from Leupold, Vortex Razor HD II, Vortex AMG, Bushnell XRS II or DMR II, Tangent Theta, and probbaly a couple others I'm missing, buy large objective lenses because the corresponding larger exit pupil makes it easier to see through when you're shooting fast or doing wierdo positional work. If you're on a budget, buy the smaller objective lens and know that if you notice the image is darker than you'd like, dialing down magnifcation slightly will yield a noticeably brighter image.
The cliff notes version of the article is the optics-buying community obsesses way too much over size of the objective lens and fails to account for the effect of the erector assembly has on the amount of light passing through a scope. Yes, a larger lens lets more light pass into the scope; however, both the objective lens and the erector assembly determine the size of the exit pupil and the exit pupil is what really determines how much light makes it to your eye. It is also harder to build a larger objective lens correctly, so it costs more (this is why you should never buy cheap scopes with large objective lenses). A larger objective lens is also harder to immobilize from impacts scopes that get used will take (again, don't buy cheap scopes with big objective lenses). A poorly constructed large objective lens will let more light into a scope and yield a bright blurry image, which I find offensive.
I wrote that article because I'm tired of seeing good people feel obligated to buy a more expensive scope, just because the objective lens is bigger and "it gathers more light." I'm also tired of seeing optics manufacturers feel pressured to build scopes with massive objective lenses knowing that the image quality will take a hit (unless they jack up the price, which they don't want to do) and that the bigger lens will move more under impact, yielding point of impact shifts unless additional money is spent to immobilize it.
If you're buying anything from Nightforce, anything from Leupold, Vortex Razor HD II, Vortex AMG, Bushnell XRS II or DMR II, Tangent Theta, and probbaly a couple others I'm missing, buy large objective lenses because the corresponding larger exit pupil makes it easier to see through when you're shooting fast or doing wierdo positional work. If you're on a budget, buy the smaller objective lens and know that if you notice the image is darker than you'd like, dialing down magnifcation slightly will yield a noticeably brighter image.
Had a Nikon rep tell me that a 30 mm tube passes more light through than a 1" tube. I'd can't recall another word he said before I walked away...
There's only so much discussion possible, but "better erector assembly" ...
doesn't seem completely detached from light transmission, eg
Its all relative of course to "better" than what..
It's good that you bring attention to the issue of how quality assembly and materials are an important factor in determining a scope's performance. However, the article's title is (obviously by design) a bit provocative - it sounds like internet click-bait. Maybe your editor came up with that idea? Not attacking your knowledge or credibility in any way, just registering my own small objection to an editorial trend that seems to have become more widely used in the publishing business in recent years. Maybe it's just me, but I accept information more readily - particularly technical information - when it's presented in a calm, sober manner.
The objective isn’t the only lense.
The objective can be huge, but if the other lenses don’t compliment it, it doesn’t matter. The tube and erector housing can dictate some things with these lenses.
Hi,
LOLOL Yea "Tagging" is correct. The modern day version of finger pointing and saying "That guy right there is whom you need to talk to".
Side Note: Please let me know if you have any openings for a new precision rifle review/article later around June timeframe.
Sincerely,
Theis
Thanks for everyone who has chimed in on this especially the author of the article. My curiosity on this issue stems from a post from Terry Cross in 2018 then i was further intrigued by this article. He quotes someone in the know stating that the 50 mm ACTAR is longer and heavier all to provide 40 seconds more twilight time over the 42 mm ACTAR with less forgiving parallax.
My point being it seems like we scrutinize over every detail of scopes these days but when it comes to objective lens its just bigger is better and gathers more light but can we quantify that how much better? For me I would much rather have a 42mm ACTAR over a 50 MM ACTAR if the difference is 40 seconds of twilight time.
If your running a PRS gun would you change your thought process from a 56 mm objective if you found out that a 42mm objective just had a minute and a half less twilight factor and you could get that in a more compact lighter scope?
My point being it seems like we scrutinize over every detail of scopes these days but when it comes to objective lens its just bigger is better and gathers more light but can we quantify that how much better? For me I would much rather have a 42mm ACTAR over a 50 MM ACTAR if the difference is 40 seconds of twilight time.
If your running a PRS gun would you change your thought process from a 56 mm objective if you found out that a 42mm objective just had a minute and a half less twilight factor and you could get that in a more compact lighter scope?
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Hi,
LOTS have changed in the optics world since 2018.....that would be like attempting to compare cell phone article from 2018 to cell phone capabilities right now.
Also..."light gathering" has way more to do with things than just "twilight" utilization.
Sincerely,
Theis
LOTS have changed in the optics world since 2018.....that would be like attempting to compare cell phone article from 2018 to cell phone capabilities right now.
Also..."light gathering" has way more to do with things than just "twilight" utilization.
Sincerely,
Theis
When ever light passes through a different medium, some light is lost, which means the more lenses the more losses. (this is where the different coatings come into play) So light transmission is about the whole optical system and not just a bigger objective lense or any other lense for that matter.
I think the main problem in the optics world is that many marketing departments are throwing around fancy words without fully understanding them.
I think the main problem in the optics world is that many marketing departments are throwing around fancy words without fully understanding them.
Unless you have access to an optical laboratory AND have the education and experience to understand optical physics, no, you can't.
Theis,
I understand what you saying so lets fast forward to today. If i ordered a brand new Nightforce ACTAR 4-16 by 42mm and a 4-16x50 mm ACTAR what is the extra 8mm objective lens on the 50mm giving me? I may not be using the terms "light gathering" or "twilight utilization" so I apologize but please explain to me what that extra 8mm objective is going to give me?
It appears that in 2018 someone "in the know" told Terry Cross all it gave was a 40 second difference in "twilight utilization".
Gunny Sergeat i don't have access to an optical laboratory and nor a degree in physics but I am sure all of the major scope manufactures do and that is my point i think people in the know, know the only quantifiable difference between the 42mm ACTAR and 50 mm ACTAR was 40 seconds of twilight factor.
We scrutinize these scope in every way my point is if we could quantify the difference between a 42 mm objective vs a 50mm and determined its not that much different we may want scopes designed with smaller objectives as opposed to own i just need to get the bigger one.
I understand what you saying so lets fast forward to today. If i ordered a brand new Nightforce ACTAR 4-16 by 42mm and a 4-16x50 mm ACTAR what is the extra 8mm objective lens on the 50mm giving me? I may not be using the terms "light gathering" or "twilight utilization" so I apologize but please explain to me what that extra 8mm objective is going to give me?
It appears that in 2018 someone "in the know" told Terry Cross all it gave was a 40 second difference in "twilight utilization".
Gunny Sergeat i don't have access to an optical laboratory and nor a degree in physics but I am sure all of the major scope manufactures do and that is my point i think people in the know, know the only quantifiable difference between the 42mm ACTAR and 50 mm ACTAR was 40 seconds of twilight factor.
We scrutinize these scope in every way my point is if we could quantify the difference between a 42 mm objective vs a 50mm and determined its not that much different we may want scopes designed with smaller objectives as opposed to own i just need to get the bigger one.
Hi,
You cannot quantify something that is different for every single person
For example---due to my eye injuries I cannot see worth a shit through a March scope, no matter what the Obj diameter is...their coating makes everything cloudy to me.
If you want a 42mm then get it but you are not going to change the designers and manufacturers mind because their lab equipment tells them the larger is better (caveat being a legit top tier mfg to begin with).
Sincerely,
Theis
You cannot quantify something that is different for every single person
For example---due to my eye injuries I cannot see worth a shit through a March scope, no matter what the Obj diameter is...their coating makes everything cloudy to me.
If you want a 42mm then get it but you are not going to change the designers and manufacturers mind because their lab equipment tells them the larger is better (caveat being a legit top tier mfg to begin with).
Sincerely,
Theis
No, not everyone does. Those who do likely don't have enough knowledge to understand what they're obsessing about.
I don't know shit about optics. But I'm quite knowledgeable (from professional education and experience) about other technical topics that frequently are discussed in gun forums.
Suffice it to say most of what i read here and elsewhere is way the hell off from reality.
I think the reality with optics is that most people on here, myself included, buy optics because they both meet the perceived use case (weight, magnification, reticle preference) and because they are satisfied from what other people, including the companies themselves, say, that they will not be missing out on performance by buying the optic in question. It is not a best case scenario because, as you mention, none (few) of us has the ability to test these things beyond click values being true and them appealing to our personal eyes. I assume this is why we all gravitate to the same few scopes. It actually is a pretty shitty way to decide, but it is what we have, and who wants to leave all of that perceived performance on the table for just a few hundred bucks more?
And unless your budget is unlimited, many choices are already made for you before you start shopping.
I want a bionic eye to take advantage of the coatings being derived in the optic industries. It is amazing what's coming down the pike.
Texas,
This is an excellent question and a good example to use. First, the ATACR is always a good choice. NF has high standards when it comes to all aspects of performance and they’re unforgiving of anything that doesn’t measure up.
The important thing to remember is the only aspect of a scope with which your eye interfaces is the exit pupil. Have a buddy shine a flashlight into the objective lens, stand back a couple feet, and look at the ocular lens (the back of the scope). You’ll see a small well-lit circle. That’s the exit pupil and that’s all your eye sees when you look through a scope. Watch what happens to it as you dial down magnification. It gets bigger quickly.
The size of the exit pupil is determined by dividing the size of the objective lens by the magnification. The 50mm objective yields an exit pupil of 3.125mm at 16X. The 42mm objective yields an exit pupil of 2.625mm. This is a big assumption, but assuming your eye can see the difference between a 3.125mm exit pupil and a 2.625mm exit pupil, the larger objective lens will give the brighter image. This is why Terry Cross (who is one of my all-time favorite dudes) said the larger lens gets you an extra 40 seconds of twilight visibility. I think that’s an accurate assessment and valuation.
However, if you’re willing to dial down magnification of the 42mm objective lens to 13.5x instead of 16x, the smaller objective lens will yield an image of equal brightness to the larger objective lens because the exit pupils are now the same size.
My personal preference in this case would be to buy the 4-16x42mm. I like the smaller size, especially if the rifle lacks an adjustable comb. The larger lens would require taller rings, which pulls the shooter’s head off the stock, making it less likely he’ll be able to spot impacts when the rifle recoils.
The advantage the larger objective lens has is the larger exit pupil under all shooting conditions. The shooter can’t see through the scope unless his eye is lined up behind the exit pupil, so the larger exit pupil is easier to get a full field of view, especially when you’re in a hurry. This starts to matter when you’re on the clock or when you’re shooting from compromised positions. When it comes to an optic like the ATACR, these last two paragraphs are what drive my decision process. “Gathering light” is never a consideration.
The only time I’ll always favor a smaller objective lens is when scope construction is questionable. When shopping on a budget, you’re more likely to get better image quality and less point of impact shifts with the smaller objective lens because it’s easier to make and easier to stabilize. This applies to all scopes that cost less than about 1000-1200 dollars. The exception here is Leupold. Leupold has good image quality across all their scope lines and they do well with minimizing point of impact shifts.
I hope this makes sense. I’m banging it out on my phone from the Atlanta airport and my thumbs are exhausted.
This is one of the reasons why I like so much the now discontinued Steiner P4Xi 4-16X56. For a budget scope, its brightness, eye relief, and exit pupil are phenomenal and their combination yield an extremely forgiving and easy to get behind scope.
As a plus, the higher position over the rifle required by the larger objective (compared to the 42 mm scope I had on that rifle) forced me to move the stock's comb up to match and I found it a lot less stressful on my back and neck in prone.
It's an interesting question. DXOMARK tests optics with lots of pretty objective measurements. If only they could do riflescopes.
