Scout scope vs. iron sights - forest hunting

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I have used all three; dots, irons, and scopes. Up until last year, I prefered 3-9 or 4-12 scopes. I tried see through mounts but didn't use them. I like red dots but I am trying a 1-4 this year. The reason being I can no longer see the sights and the deer at the same time unless I have lots of time. Last year I could not find moving deer in the thick brush with a 4 power scope in part because I was on a stand that did not allow me to turn my body quickly. I got a deer but not the one I saw but did not get a good shot at. Good points for both but you have to find what you like. Irons are quicker if your eyes are good, the light is good and you practice. Otherwise I'd try a red dot or low power 1-4 scope. 3-9 or 4-12 work well if you have good sight lines.
 
Scopes transmit light. They do not "gather light" in the sense some believe they do. All scopes lose some percentage of light, none of the them transmit 100% of the light available. By using larger lenses and better coatings they can lose less light, thereby making them brighter than other, lesser scopes, but NO conventional scope transmits a brighter image that available light. Larger, yes; clearer, yes; brighter, no.

It is impossible for any scope to "gather" light. It can only transmit existing light. And, regardless of advertising claims you may have heard, there is no riflescope made that can transmit 100% of available light....

The very best rifle scopes human beings can create will transmit to your eye—under perfect conditions—a maximum of 94.5% to 95% of available light.

http://www.schmidtbender.com/facts_light.shtml

Now if you want to argue this point, find a quote that explicitly states that a scope can offer an image brighter than ambient from a source you think knows more about riflescopes than Schmidt & Bender and include a link to it.

Please no more fuzzy analogies about funnels, magnifying glasses, "gathering light" or displays of ego. We've had enough of those already.

Here's some more:

Scopes don't gather light, as most people think, although the term "light gathering ability" has become accepted jargon. Scopes transmit available light through the lenses to your eye, always losing a bit in the process. The best a scope can hope to offer in light transmission is about a theoretical 98%, which only the very finest (read expensive) scopes can hope to approach. Anything above 95% is considered great, and most scopes are around 90%, give or take a bit.

http://www.opticsplanet.net/how-to-choose-riflescope.html

So what's the big deal about large objectives? Aren't they supposed to be brighter?

Indeed they are, but they are only brighter than other scopes, not ambient light and only under certain conditions. Here's how it works:

The ratio between the objective lens and and the magnification of a scope is called the exit pupil. For example a 40mm scope at 8 power will have an exit pupil of 5mm. (40mm/8) For a given size of objective lens, a scope with higher magnification will have a smaller exit pupil.

Depending on how bright it is, the diameter of the human pupil varies. If the exit pupil is larger or equal to the diameter of the eye's pupil looking through the scope both scopes will appear to be similar, since the eye's pupil will act as a bottleneck on the amount of light that gets in. OTOH, if it's relatively dark and the pupil is wide open (~7mm), then a scope with an exit pupil less than 7mm will be the bottleneck and appear darker than one that has an exit pupil at or above 7mm.

There's a good writeup on exit pupil here:

http://en.wikipedia.org/wiki/Exit_pupil

Finally, thanks to the experts at http://www.opticstalk.com/forums.html who helped me remember exactly how all this works.
 
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Perhaps you should do some heavy reading and educate yourself on "light gathering" and "light transmission"
But there is nothing inherent in glass that makes light attracted to it
Scopes transmit light. They do not "gather light" in the sense some believe they do.
Weird. Three separate posters (two on this thread) feel that it is necessary to invoke the idea that "some" folks out there believe that light is "attracted" to glass, and that that belief--that they themselves seem to have invented--is what others (like myself) mean when we use the term "light gathering". Even though I have repeatedly said I mean by the term--and I suspect, unless I am unique, others mean by it--a scope (probably with large objective, large exit pupil and low power) that presents a brighter picture to the eye then the naked eye would see.

Perhaps some out there believe that an optical scope can never present a brighter picture than the naked eye can see, and that's why they object to the term "light-gathering". If so, I think they're wrong. But perhaps someone can present a reference that says that scopes can NEVER present a brighter picture than the naked eye sees. I'll wait.

Others seem to insist that the term "light-gathering" implies the voodoo-like attracting of light (perhaps around corners and from under tables), or ability to alter light before it reaches the scope. These same persons insists that scopes only "transmit" light, and don't seem to admit that scopes can also "converge" it or "concentrate" it. I think such posters are clearly wrong, too.

Perhaps someone can introduce me to the persons who use "light gathering" to mean something other than "presenting a brighter picture than is seen by the naked eye"? Or references that say that light gathering can only mean voodoo, and is not allowed to mean something more straight-forward and common-sensical? Even a poll that says most people who say "light gathering scope" mean a supernatural scope?

I feel like I used the term "expanding bullet" and am being attacked: "Don't you know about physics? There is conservation of MATTER! Matter just can't expand and become suddenly MORE matter than it was before you shot it." Deliberate misinterpretation of a perfectly reasonable, commonly used, well understood term as something that defies physics.
 
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I often hear someone say that his scope is very "bright" as if others are no so. It seems to me that some scopes are brighter than others, or is it that some scopes are clearer than others and have a larger field? I think the latter. Certainly good scopes are better than bad ones, but if they are all nearly as bright as the rest then why spring for an expensive scope in the first place? Are expensive scopes really that much better?

I think it is a valid question, since it can mean buying a cheaper rifle so that we can afford high priced glass.

As I've said before, for most hunting I prefer an appeture sight. For small varmits and long, open range hunting, a scope is good too, but since most game is taken at close range why bother?
 
At the risk of being pounced upon, I am enjoying this thread and subsequent hockey match that seems to have erupted somewhere along the way...
 
A scope cannot make the object brighter, but it can make an object more visible. It does this by the magnified image being picked up by more retinal cells than the smaller, unmagnified image. This is assuming the exit pupil of the scope is equal to or larger than the current entrance pupil of the eye.

I prefer iron sights in thick woods, I can still see well enough to use them, not sure how much longer that will be the case. Mainly because of the chance of having to take a shot at a running target, it happens sometimes and a scope, for me, is pretty much useless for that.
 
A scope cannot make the object brighter,
Can't make the object brighter? Of course not.

But it can't make the image of the object presented to the eye brighter? Why not? I'll take either your opinion or a reference.

If an object reflects light in all directions (standard, diffuse, "non-specular" reflection), then more of that object's reflected light will fall on a large lens than on a small one; that is, more on a 24mm objective lens than on the 12mm human cornea.

If all the light that falls on the cornea is focused into a 1mm tall image of that object, that image will be 1/4 as bright as the image produced by focusing all the light from the 24mm objective lens (assuming similar diffraction, reflection and transmission losses).

If this 4 times brighter image derived from a 4 times (area) greater lens surface "can't" or "doesn't" happen, why not? (Do engineers who design huge dish radio telescopes understand that that the large dish does nothing to "gather" radio waves better than a much smaller antenna can do? :rolleyes:)
 
Get yourself a 1.5-6x40. Pretty much the ideal scop for everything except shots over 300 yards. I just mounted a 1.5-6x40 Burris Euro Diamond on top of a Browning BAR LW stalker in 308 and I can tell you it's going to be the perfect gun for the big northern MN woods.
 
Weird. Three separate posters (two on this thread) feel that it is necessary to invoke the idea that "some" folks out there believe that light is "attracted" to glass, and that that belief--that they themselves seem to have invented--is what others (like myself) mean when we use the term "light gathering". Even though I have repeatedly said I mean by the term--and I suspect, unless I am unique, others mean by it--a scope (probably with large objective, large exit pupil and low power) that presents a brighter picture to the eye then the naked eye would see.

I've never said anything a rational person could confuse as "light is 'attracted' to glass". That's an argument YOU made up. I'm just saying that there's no such thing as "gathering light" as a way to make an image brighter than ambient. Since I don't believe in the principle, I'm hardly going to offer explanations on how it "works".

Perhaps some out there believe that an optical scope can never present a brighter picture than the naked eye can see, and that's why they object to the term "light-gathering". If so, I think they're wrong. But perhaps someone can present a reference that says that scopes can NEVER present a brighter picture than the naked eye sees. I'll wait.

It's already been done, but yet again you've chosen to ignore anything that you don't like:

The very best rifle scopes human beings can create will transmit to your eye—under perfect conditions—a maximum of 94.5% to 95% of available light.

http://www.schmidtbender.com/facts_light.shtml
Now if you want to argue this point, find a quote that explicitly states that a scope can offer an image brighter than ambient from a source you think knows more about riflescopes than Schmidt & Bender and include a link to it.

Please no more fuzzy analogies about funnels, magnifying glasses, "gathering light" or displays of ego. We've had enough of those already.

That should have been explicit enough. Seriously, what part of
"The very best rifle scopes human beings can create will transmit to your eye—under perfect conditions—a maximum of 94.5% to 95% of available light."
is too subtle for you?

Again, find a source that explicitly backs your point, if you can, and post it along with a link. Otherwise just stop.
 
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Since I don't believe in the principle, I'm hardly going to offer explanations on how it "works".
Whether you believe in it or not is immaterial. Whether you believe in gravity or not is immaterial: physics says it exists--even in "weightless" outer space.

So, what I was asking is do YOU have any rational basis for saying the image from a scope can never be brighter than the image seen by the naked eye, or not? So far, none has been presented.
"The very best rifle scopes human beings can create will transmit to your eye—under perfect conditions—a maximum of 94.5% to 95% of available light."
is too subtle for you?
Nothing. But if that is 94.5-95% of FOUR TIMES the light that falls on the unaided human eye, then it will be brighter by far.

What part of that math is too complicated for you? :neener:
Again, find a source that explicitly backs your point, if you can, and post it along with a link. Otherwise just stop.
Uh...no. You find a source that says a scope can NEVER present an image that is brighter than what the human eye can see. That way we BOTH have to produce statements to "prove" our points, not just me.

And by the way, you were probably sleeping, but did you TRY that low-light performance calculator for scopes? Did you enter 24mm lens, 10.9 pupil, and 91% transmission--and see what relative brightness you got?

Did you even bother to engage your common sense to figure out why observatories, using large mirrors as lenses are able to see dimmer stars than we can with the naked eye--if there's no such thing as light-gathering?

:D
 
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Larger lenses receive more light than smaller ones. Better quality lenses transmit more light than cheaper ones. Better coatings allow the lens to transmit more light than those without. None of which adds up to "gathering".

Radio antennas are the same way. Larger antennas receive more radio waves. It is not "gathered".

The subject of "light gathering" and whether or not a scope presents a brighter image than the naked human eye are mutually exclusive.

Are you really this dense? Are you going to turn the world of quantum physics on its ear???
 
{Radio antennas are the same way. Larger antennas receive more radio waves. It is not "gathered".}

Not quite.

In essense, the radio dish (or other directional design)antenna acts to narrow the field of view. (Basically, the antenna pattern is the Fourier transform across the aperture loading).

Technically, all antennas receive energy from all directions. The antenna design acts to increase the directional sensitivity so that it "sees" in some directions better than others. After the signal is received, it must then be amplified to a level appropriate for the use of the energy.

What does this have to do with rifle scopes? Quite a bit, actually. First, it must be understood that anything between the eye and object will tend to decrease the amount of energy transmitted to the eye. Second, every thing between the eye and the object adds noise to the image. Third, in order to consider the sensitivity, you have to consider the entire optical system, i.e. scope, eye, and brain. The first two items imply that a premium is placed on the optics that degrade the image the least and allow the most energy to pass through. The third and fourth items have been missing in this discussion.

The "Brightness" is a measure of how much energy is transmitted. In a well designed scope, a bigger objective will let more energy through than a smaller objective all other things being equal. However, why would it appear brighter? Well, think of the pupil of the eye. In the dark, the pupil gets bigger, letting more light in. The scope restricts the field of view. If you are looking at something against a dark background through a scope, the pupil of the eye will adjust to the amount of light transmitted allowing the object to be more easily seen.
 
Did you even bother to engage your common sense to figure out why observatories, using large mirrors as lenses are able to see dimmer stars than we can with the naked eye--if there's no such thing as light-gathering?
:D

natman said:
It is impossible for any scope to "gather" light. It can only transmit existing light. And, regardless of advertising claims you may have heard, there is no riflescope made that can transmit 100% of available light.

The article is entitled The Truth About Light Transmission and that's what it is.


natman said:
The very best rifle scopes human beings can create will transmit to your eye—under perfect conditions—a maximum of 94.5% to 95% of available light.
http://www.schmidtbender.com/facts_light.shtml

But if that is 94.5-95% of FOUR TIMES the light that falls on the unaided human eye, then it will be brighter by far.

I should have thought that the meaning of the Schmidt & Bender quote was clear enough that anyone could understand it. But apparently not.

So you want to base an argument on twisting the meaning of the word transmit so that while the scope transmits 95% of available light, somehow there's FOUR TIMES more light, so 95% of 4 is brighter?

OK, fine. Kindly explain exactly how this FOUR TIMES as much light is produced. Show the formula that explains what configuration of scope would produce this FOUR TIMES, rather than, say, THREE or FIVE. If there's any truth to your claim, there's a formula out there to calculate it. Please spare us your semantic gymnastics - PROVIDE A REPUTABLE SOURCE and cite it. And please, no whining how it's not your turn to provide a source.
 
The article is entitled The Truth About Light Transmission and that's what it is.
So those large observatory telescopes are just a hoax? Great.
somehow there's FOUR TIMES more light, so 95% of 4 is brighter?
Not somehow, Nat: because the 24mm objective lens represent a 4 times greater area than the 12mm human cornea, 4 times more light falls on it. My reliable source: Area = pi * r^2

And yes: 0.95X4 is > 1. Need a source for that, too?
 
Y'all need to ask yourselves how this contest to get the last word in actually helps address the OP.

Please.
 
I hunted with peeps all my life and would have no other except sooner or later age ruins the eyes and then it is scopes only. I'd use peeps anyday for one reason, rain, it is a lot easier to get a clear sight picture that it is with any scope.
 
So those large observatory telescopes are just a hoax? Great.Not somehow, Nat: because the 24mm objective lens represent a 4 times greater area than the 12mm human cornea, 4 times more light falls on it. My reliable source: Area = pi * r^2

Can't fault the math. You've managed to calculate the areas of the circles correctly. The rest is just pitiful. So your theory is that the ratio of the brightness of the image to available light = area of the objective lens/the area of the cornea. Well that's certainly simple enough. Yet, with all the resources of the internet at your fingertips, you can't find one single source ANYWHERE to back it up. What a surprise!

All these optical experts have been wasting their time with exit pupils and lens coatings when all they had to do was make the OL bigger. I guess if they make it big enough you'll have to wear sunglasses to look through your scope at night. I'll notify Schmidt & Bender of their error right away. Expect a call from the Nobel committee any day now. :rolleyes:

I usually try to avoid engaging in personal criticism, but your case warrants an exception. I knew when it came down to verifying an actual fact you'd be exposed as the fraud you are. You may think it's fun to play the troll and aggravate people, but in the end all you've accomplished is to make a complete fool of yourself.

Find something better to do with your time in the future than to waste mine.
 
Why are we arguing theory when we can do a practical experiment to settle the question?

Take the most powerful magnifying glass you can find outside on a sunny day, and focuss the sun on the back of your hand. Hold it for a full minute.

Come back and tell us what happened.;)

(This experiment shows that heat can be gathered or concentrated by a lens. And heat differs from light only in wavelength.)
 
Here's a thought: does a scope with a very large front lens appear brighter than the relative brightness of a scope with a noticeably smaller front lens? I suggest that is does. Is this because the large lens with a greater surface area allows more light in? Seems so. As I stated earlier some scope do appear brighter than others and I'm wondering why. I think we who have looked through many scopes have noticed this.

Or do we just look through a lens and see the light that is on the other side? Wouldn't a large lens "see" more light? Can we also say that the larger lens therefore, "gathers" more light since it sees more and the target area appears brighter? However can a scope make apparent light brighter than ambient light? In other words can a scope make things brighter than they actually are? This is the crux of the question. Which is, does the target area look brighter when viewed through a scope compared that what which is seen with the naked eye?
 
Which is, does the target area look brighter when viewed through a scope compared that what which is seen with the naked eye?

A 40mm objective scope is basically taking 40mm of light and focusing it on a 10mm pupil. Therefore your pupil seems to be seeing 4x the light it usually would. With higher end optics with better lenses/coatings/transmission ratings the effect is enhanced as less light is lost between the objective and your eye.
 
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