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Light transmission

Einstein, the physics guy, theorized that light was particulate in nature vs. wave like and could be absorbed or generated as a whole entity. The limits of todays glass optics don't really improve stuff - what is needed is a tiny 28 mm diameter light sucker scope attracting these particles that might have mass. How much can glass optics be improved - I would guess not much in the optics or lens department. I looked through a big Zeiss 60 mm scope once and was thrilled before seeing the price - higher price Leupold's are ok and other comparable price scopes probably match those.
 
Let me put it this way by asking a question. How many 3-9 or lesser magnified scopes have 56mm objectives? Higher magnification scopes have larger objectives so they can be used in lower light at higher magnifications and this is where exit pupil comes into play. The human eye can only dilate to 4-6mm on average and the lower magnified scopes do not need the larger objectives to reach the 4-6mm window. I would also say IMO that 50mm objectives in these lower magnifications are a waste. Larger objectives only provide a larger exit pupil at higher magnifications and do not transmit more light.

If you have a variable and you want more light transmission turn down the magnification.
 
If you read my first post I stated that objective size has little do with light transmission not nothing to do but not as much as some think.

The human eye can only take advantage of so much exit pupil size and the rest is wasted or not utilized.

I did not even want to get into the 30mm discussion about light transmission because that would open up another can of worms.

For coyote hunting I run a Swarovski Z6 2.5-15x44 and it is superb in low light and only has a 44mm objective. The only scope that would come close that I have owned was a S&B Klassik with a 42mm objective.

The S&B 3-27X56 I owned was one of the worst low light scopes I have ever owned.

You are definitely describing the difference in glass and coating qualities with the scopes mentioned. Cant compare a 3-27x56 S&B to a 2.5-15x44 Swarovski and come to the conclusion that objective size doesn't matter. They are two totally different scopes with different glass and coatings.

Swarovski has always been one of the best on low light. Swarovski makes that same 2.5-15X Z6 scope with a both a 44mm and 56mm objective. If you compared the two side by side in low light, you would start to notice better low light performance on power settings above 6X with the 56mm model and the difference would become more drastic as you increased the magnification.

I will also have to disagree you on the 'funnel' comment. Scopes are a sort of 'light funnel' in the sense that with all glass and coatings being the same, the difference comes down to surface area of the front objective. The larger the surface area, the more light that can enter the scope and be available for transmission to the exit pupil as magnification levels are increased. Think of the larger objectives as a larger fuel tank and the distance you can drive as magnification level. You can travel farther with more fuel reserves. Again, keeping in mind that all glass, and coatings are equal.

Now granted, there can be extra light in the exit pupil that will not increase the quality of the image in the centwr of the view due to our eyes only being able to handle about 7mm of light, but it is NOT wasted. The extra light can create a larger 'sweet spot' in the field of view and a more forgiving eye box where a full picture is maintained with larger degrees of head movement.
 
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Scopes are not funnels. It does not work that way.

Um............. actually it's funnels that don't work that way. If you assume a constant pressure, a larger funnel bell does not increase the flow; they just catch spills better.

In short, large lenses are effective because light is not motor oil.
 
Check out on the www, "Scope, Optics & Ballistic info & faqs". It's a long but informative read. Barlow
I don't know if any of you read this above article, but if I understand it correctly, the diameter of the objective lens has nothing to do with gathering more light,(false advertising by some imo) but does aid in resolution of the objects you are looking at. Quality of glass, and lens coatings allow more available light to come thru the scope, the size of the bell or the difference between 30mm and 1 inch tubes has no effect. This is what I get from this well written and detailed summary. Barlow
 
I don't know if any of you read this above article, but if I understand it correctly, the diameter of the objective lens has nothing to do with gathering more light,(false advertising by some imo) but does aid in resolution of the objects you are looking at. Quality of glass, and lens coatings allow more available light to come thru the scope, the size of the bell or the difference between 30mm and 1 inch tubes has no effect. This is what I get from this well written and detailed summary. Barlow

You are not understanding it correctly. I posted the portion of that thread below.
Please explain how you came to that conclusion??? The fella who posted that info makes a stupid comment at the beginning because he completely contradicts himself later with the explanation.

The front objective and magnification level determines the size of the exit pupil. The glass and coatings determine what percentage of available light gets through that window. And the extra pupil window light is not totally wasted. I explained why earlier.

This the direct quote from that 'forum thread' you are referencing. I highlighted the contradiction to his beginning statement and made notes in ( )

SCOPE BRIGHTNESS AND LIGHT GATHERING

LENS SIZE
It’s not all about the size of the objective lens. Riflescopes with monster objectives may actually transmit less light than much smaller instruments. (
Due to different glass and coatings, not objective sizes)
Yes, the big front window does let light in, but it’s the size of the exit window that determines how much of that light gets into our eyes. (Exit Pupil)
The quality and quantity of anti-reflection coatings enhance or degrade brightness too.

How does it work?
The objective lens lets light/image in.
Several internal lenses pass that image on to the eyepiece where it is additionally magnified and passed out to our eyes.
The higher the magnification, the smaller the exit window, commonly called Exit Pupil (EP.)
The scope’s EP corresponds to our pupils, which dilate to a maximum of 7mm in a young person, declining to about 5mm by age 50 and another millimeter each decade after that. If a scope’s EP exceeds the diameter of ours, the rim of extra light spills out onto our irises, wasted.

You can see the EP of any optic by holding it at arm’s length toward a bright area and looking at the eyepiece lens. That little bright circle is the EP. Through it pass all the waves of light making up the image of that deer you’re hoping to shoot. If you have a variable power scope, turn the power ring and watch the EP change diameter. Reduce power and the EP enlarges. Crank power up and it decreases.

* EP is calculated by dividing objective lens diameter by magnification. * (so explain how larger objectives don't matter?????)
Thus, a 40mm scope at 4x gives a huge 10mm EP. Cranked up to 10x, the instrument still delivers a 4mm exit pupil. A 4mm EP provides more than sufficient brightness for targeting a deer at one-half hour after sunset on a cloudy day in the woods (or legal shooting hours most places). An optic with an exit pupil of 1.3mm restricts light transmission to such a degree the optic's effectiveness is rendered almost useless.

As an illustration of how all factors optical are co-dependent, magnification and image quality come together at a specific exit pupil diameter regardless of the much advertised twilight factor. When a combination of objective lens and magnification dips below 2.5mm, image quality suffers substantially. Above 2.5mm, image quality becomes more apparent, as each increase in exit pupil diameter enhances resolution and contrast.
 
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Let me put it this way by asking a question. How many 3-9 or lesser magnified scopes have 56mm objectives? Higher magnification scopes have larger objectives so they can be used in lower light at higher magnifications and this is where exit pupil comes into play. The human eye can only dilate to 4-6mm on average and the lower magnified scopes do not need the larger objectives to reach the 4-6mm window. I would also say IMO that 50mm objectives in these lower magnifications are a waste. Larger objectives only provide a larger exit pupil at higher magnifications and do not transmit more light.

If you have a variable and you want more light transmission turn down the magnification.
Let me see if I can explain it to you in terms which with you can relate. I trust you are familiar with the ballistic coefficient of a bullet. This represents a factor by which the bullet slows down after leaving the muzzle and encountering air resistance. A higher BC means the bullet slows down more slowly and a lower BC means the bullet slows down more quickly. Under no ordinary circumstances will a bullet accelerate after leaving the barrel. At the recently concluded Nationals in Lodi, the ETs provided the velocity of the bullets at the target. I can assure you that none of the bullets fired during that event were faster at the target than at the muzzle. There are two things one can do to make the bullets arrive faster (keeping bullet weight constant,) one is to select a high BC bullet to reduce the rate of loss in the air and the other one is to push the bullet faster.

Think of a riflescope with no lens coating as a low BC bullet and one with great multicoating as a high BC bullet. Now think of larger lenses as higher muzzle velocity. Larger lenses receive more light (higher MV) than smaller lenses (lower MV) and given the same level of coating (same BC) will transmit more light, or allow more light through (higher terminal velocity).

Now, I agree with you that large lenses are not needed at lower magnifications and daylight, but at higher magnification, the larger lenses make a difference, all else being equal. I've shot with a T-36X40 and I am much happier shooting with a March 5-50X56 at 40X, especially in the early morning relays of November/December matches.
 
Off of the Nightforce home website. Article by Tom Bulloch, "See the Light-Light transmission". He states, truth number 1, "there is NO riflescope made that can Gather Light". Read the article and argue with him. Barlow
 
Off of the Nightforce home website. Article by Tom Bulloch, "See the Light-Light transmission". He states, truth number 1, "there is NO riflescope made that can Gather Light". Read the article and argue with him. Barlow

Of course they don't "gather" light. They can only make use of what is available in the atmosphere. A larger objective makes better use of it. Think about the meanings of the words you are posting.

Nightvision scopes don't "gather" the light either. They 'amplify' the available light which is why they won't work in an environment where no light exists.
 
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Off of the Nightforce home website. Article by Tom Bulloch, "See the Light-Light transmission". He states, truth number 1, "there is NO riflescope made that can Gather Light". Read the article and argue with him. Barlow
Right, riflescopes ACCEPT light into the system. And a larger lens ACCEPTS more light than a smaller lens. Riflescopes are passive devices.

Or, if you're really hung up about saying that a scope does anything, try this: More light gets into a bigger lens than a smaller lens.
 
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Off of the Nightforce home website. Article by Tom Bulloch, "See the Light-Light transmission". He states, truth number 1, "there is NO riflescope made that can Gather Light". Read the article and argue with him. Barlow

Oh, and I love how you reference a company, NightForce, who primarily uses 56mm objective lenses. Why would NF waste their time with such large front objective lenses??? Think about it...

Why would ANY company make scopes with large front objectives if it didn't matter? I guess none of the optics manufacturer's know what they're doing...
 
The larger the objective lens, the more light that can pass through it, and the brighter the image at a given magnification. As power increases, the need for light also increases. A 4x32 scope is brighter than a 12x40 scope because the 32MM lens does more for the lower power than the 40MM does for the higher power.
 
Oh, and I love how you reference a company, NightForce, who primarily uses 56mm objective lenses. Why would NF waste their time with such large front objective lenses??? Think about it...

Why would ANY company make scopes with large front objectives if it didn't matter? I guess none of the optics manufacturer's know what they're doing...
I did think about. Why not reference Nightforce, they build one of the best scopes in the industry. There are evidently reasons for large objective lenses (resolution) but according to Nightforce gathering light ain't one of them. If you had a 1 inch scope with a 1 inch objective lens and all the lenses in that scope were properly coated, it would TRANSMIT more light than a 50mm objective lens with no lens coatings. Resolution, and light transmission (according to what I have read) are two separate and measurable things. I think that is where the confusion is. Argue with them not me, if you're convinced you're right, so be it. I will side with them. Barlow
 
I did think about. Why not reference Nightforce, they build one of the best scopes in the industry. There are evidently reasons for large objective lenses (resolution) but according to Nightforce gathering light ain't one of them. If you had a 1 inch scope with a 1 inch objective lens and all the lenses in that scope were properly coated, it would TRANSMIT more light than a 50mm objective lens with no lens coatings. Resolution, and light transmission (according to what I have read) are two separate and measurable things. I think that is where the confusion is. Argue with them not me, if you're convinced you're right, so be it. I will side with them. Barlow

You can't compare different glass and coatings to draw a conclusion on the effects of objective size to light transmission. How many times do I have to reiterate this? Do I need to make my font size bigger on the typing and highlight it in bright colors? We are all well aware of the part the glass and coatings play in light transmission, but that's not what we are talking about.

Nowhere in the article you referenced did it describe anything to do with the varying sizes of front objective lenses and their effect on light transmission. Don't know if Bulloch missed it or doesnt uderstand it. So I'm not sure where you think you are getting these facts from? Call NightForce yourself if you don't believe me. I know I'm right. Or better yet, call Swarovski who does not outsource their glass manufacturing to some Japanese company.
 
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You can't compare different objective sizes using different glass and coatings to draw a conclusion. How many times do I have to reiterate this? Do I need to make my font size bigger on the typing and highlight it in bright colors?

Nowhere in the article you referenced did it describe anything to do with the varying sizes of front objective lenses and their effect on light transmission. Don't know if Bulloch missed it or doesnt uderstand it. So I'm not sure where you think you are getting these facts from? Call NightForce yourself if you don't believe me. I know I'm right. Or better yet, call Swarovski who does not outsource their glass manufacturing to some Japanese company.
No argument here… however, the best Japanese glass is every bit the equal of the best German glass. The difference between the best from both countries comes down to the grinding, coating, and price per unit.

Edit: When Nightforce started making scopes, they sourced their glass from Schott. When production increased, logistics dictated a different source. They haven't compromised their quality. Some of the very best optics on earth are fitted with Japanese glass, whether scopes, spotting scopes, binoculars or camera lenses.
 
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Oh, and I love how you reference a company, NightForce, who primarily uses 56mm objective lenses. Why would NF waste their time with such large front objective lenses???

Why would ANY company make scopes with large front objectives if it didn't matter?

Only because of the top end of the magnification - i.e. useable exit pupil size. The higher magnification needs the larger objective.
 
Scopes do not gather light they transmit light. The number of lenses and the coatings determine the amount of light that makes it through to our eye. This is why there is no difference in light transmission between a 1" and 30mm tube.

Objective size determines the size of the exit pupil and is usually determined by the top end of the magnification. This is why you do not see 56mm objectives on 3-9 scopes, its not needed. You could very easily put a 56mm objective on a 3-9 but the human eye would not be able to use the additional size of the exit pupil.

Large objectives bend light aggressively and are much more likely to have poorer image quality than ( if uncorrected ) than small objectives. Two identical scopes with every thing the same other than objective size compared side by side the scope with the smaller objective will have better image quality.

The only advantage to a larger objective is a larger exit pupil at higher magnification and this is why they are generally on higher magnified scopes.
 
I think it definitely comes down to better glass and coatings ... I have heard a lot about certain brands showing colors better than others.. and others seeming to have crisper images and some performing better in low light than others ... I have a cheaper brand scope that is 4-16x 50... and a much nicer/ priceir scope with the exact same power and objective ... and they are not even compareable in clarity or low light situations
 
Scopes do not gather light they transmit light. The number of lenses and the coatings determine the amount of light that makes it through to our eye. This is why there is no difference in light transmission between a 1" and 30mm tube.

Objective size determines the size of the exit pupil and is usually determined by the top end of the magnification. This is why you do not see 56mm objectives on 3-9 scopes, its not needed. You could very easily put a 56mm objective on a 3-9 but the human eye would not be able to use the additional size of the exit pupil.

Large objectives bend light aggressively and are much more likely to have poorer image quality than ( if uncorrected ) than small objectives. Two identical scopes with every thing the same other than objective size compared side by side the scope with the smaller objective will have better image quality.
This is so wrong on so many levels, I don't even know where to begin. Granted, it is more difficult to grind a larger lens and that's the reason larger lenses are more costly for the same quality, but the benefits are there. After all, there is a reason why professional photographers run around with expensive lenses on their cameras and those are big lenses.

The only advantage to a larger objective is a larger exit pupil at higher magnification and this is why they are generally on higher magnified scopes.

Because they let in more light than smaller objectives.

Anyways, I'm done with this one. We're arguing the same thing over and over again. Keep your little 32MM objective, I'll stick with my 44 and 56s.
 
This is so wrong on so many levels, I don't even know where to begin. Granted, it is more difficult to grind a larger lens and that's the reason larger lenses are more costly for the same quality, but the benefits are there. After all, there is a reason why professional photographers run around with expensive lenses on their cameras and those are big lenses.



Because they let in more light than smaller objectives.

Anyways, I'm done with this one. We're arguing the same thing over and over again. Keep your little 32MM objective, I'll stick with my 44 and 56s.
Big, is putting it mildly!30d-600.jpg
 

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