Best low light scopes?

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Meh. In my experience the term "light gathering" in the scope world is used mostly by marketers who want to convince an unassuming consumer that their optic is capable of doing something it isn't. A scope is limited by the quality of its glass and the size of its objective lens. It doesn't "gather" light from elsewhere, or amplify the available light, it merely transmits the light that available on the objective lens.

I'm sorry. I assumed we could use this established term without getting into straightforward physics of repeating energy (in this case, visible light wavelengths) conservation formula on a surface area, in regard to directional radiation from the light (energy) source, commonly known as the field of view. I'm not sure if any of the readers would actually imagine that light from any other direction than what's being intentionally refracted through to ocular is meaningful?

To make a long story short, it's simple physics. The larger the objective, the more light (energy) it can "gather" from the angle the scope will intentionally refract to what's commonly known as exit pupil. The second factor, as indicated previously, is how much light (energy) is lost in internal reflections (as determined by lens coating) and glass quality (optical transparency; impurities etc.)

In essence, for maximum low light performance you always want the largest scope, built with as few best quality lenses as possible, with the most efficient lens coating you can find and - in practise - afford.

There might be some other considerations, too. At one time I tried lugging a Hensoldt 6-24x72 around for absolutely the best possible low light performance I could have. While it's an awesome scope, having a close to 16" long, 3"+ diameter, 2.5lb scope on a rifle proved to be highly impractical.
 
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another point to consider is telescopes for looking in space, whether visible or radio-based (aka satellite dish) do the same thing (in different ways). they have the largest area practical to gather the most light or rf, and focus it on a small spot

for truly low-light application of looking at very distant, faint stars, having the best lens coatings isn't enough. they need a large lens
 
hq said:
I'm sorry. I assumed we could use this established term without getting into straightforward physics of repeating energy (in this case, visible light wavelengths) conservation formula on a surface area, in regard to directional radiation from the light (energy) source, commonly known as the field of view.

Nope, no need for the physics explanation. I'm not a physicist, and I have no need or use for any highly technical discussion of this issue. And, as I said before, I'm not trying to derail this discussion into some sort of argument over jargon. I was merely trying to make sure we were all on the same page based on some ridiculous stuff I've heard with regards to that terminology in the past.


hq said:
I'm not sure if any of the readers would actually imagine that light from any other direction than what's being intentionally refracted through to ocular is meaningful?

That's precisely what I'm suggesting, because I've had that exact argument with other shooters in regards to the "light gathering scope" issue in the past. One guy at the range was telling me how his 40mm objective scope was ideal because his scope is a "light gathering scope", which meant that it "didn't need to be as large because it pulled in other light". I've had a few of these kinds of discussions with people over the years, mostly at the gun store counter.

As such, I felt it was important to explain that point, to the best of my ability, in case the OP was under that assumption himself. Again, I see no need for the technical explanation of visible wavelengths of light, etc. I only mean to convey what is necessary for a practical look at this issue.

Anyway, since the rest of your post explains the major factors in the same way I did, I can see that you get the issue:

1) Bigger objective
2) Better lenses

So, we're pretty much in agreement. And, we also seem to be in agreement that scopes do not "gather light" in the manner that some folks I have talked to would like to suggest.
 
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That's precisely what I'm suggesting, because I've had that exact argument with other shooters in regards to the "light gathering scope" issue in the past. One guy at the range was telling me how his 40mm objective scope was ideal because his scope is a "light gathering scope", which meant that it "didn't need to be as large because it pulled in other light". I've had a few of these kinds of discussions with people over the years, mostly at the gun store counter.

Ah. Ok. That explains a lot.

I've only had the misfortune to discuss with people like that a couple of times, mainly because low light hunting is more a norm than an exception around here. Learning curve gets pretty steep when people believe sales jargon, buy cheap mid-sized scopes and find out that they can't see a thing after dusk. Sometimes when I hunt with people I haven't met before I bring a spare 50mm or larger european scope and a couple of sets of rings just in case - people with "excellent" $49.98 scopes can be rather amusing when they realize they've just spent the better part of an evening praising what essentially is junk, but I rather see everyone enjoying themselves after a successful hunt than be smug about a fact some people need to learn the hard way.

Then again, having worked in ICT customer support at one time, I know how persistent some people can be with things they think they've been promised by marketing dept... :)
 
one very subjective way to tell for yourself is to hold the scope with objective towards a light in your house. hold a sheet of paper behind the ocular. you'll see a little circle of light.

repeat with various scopes at various magnification settings and see for yourself which spot looks brighter


With this are you looking at the backside of the paper where the light shines through, or where the light shines on the paper directly after the eye piece?

Look at the front of the paper. Hold the paper 3-4" behind the eyepiece. The light will be most sharply focused at the normal eye relief distance.
Works in moonlight, too.
 
First, scopes don't "gather" light, they allow the transmission of ambient light through the lens,
Actually, they do.

You can do a simple experiment to prove this. Get a strong magnifying glass, go outside on a sunny day, and focus that glass on the back of your hand. Hold it like that for five minutes.

The result should convince you that the magnifying glass has gathered SOMETHING. ;)
 
I'll not disagree with anyone that says a bigger objective can be an advantage.

But gathering light?
Can't help but think some folks may perceive that as a vacuum sweeper suckin it in.

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The term "allow" light seems more appropriate to me.
 
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From the Cornell University Department of Astronomy website:
The main purpose of a telescope is to gather light, i.e. to collect and focus photons
 
But gathering light?
Can't help but think some folks may perceive that as a vacuum sweeper suckin it in.
I repeat my challenge:
Get a strong magnifying glass, go outside on a sunny day, and focus that glass on the back of your hand. Hold it like that for five minutes.

The result should convince you that the magnifying glass has gathered SOMETHING.
 
Gathering? Focusing?

We're quibbling here, aren't we?

And I have a quible here too: "The main purpose of a telescope is to gather light, i.e. to collect and focus photons" ?

"...Collect and focus photons"?

I'd go with "focus photons".
"...collect photons..." is a bit of a stretch. I'd have to see this guys photon sack before I'd give a thumbs up.

But, in any case: Merry Christmas guys

Doug
 
definitely quibbling

but i think people use the term 'gathering' simply to mean you get more light into your eye with the scope, acting like a funnel, than you would with your unaided eye

i.e. your pupil is say, 7mm diameter but the scope gathers 40 or 50 or 56mm of light to put into your eye
 
This seems to illustrate what is meant by gathering light:

scope.png

Makes sense to me. As a practical matter, however, getting a useful image is more important than how much light can theoretically enter the objective lens. Performance is more about coatings and design than just having a larger objective. I'd rather have a 7x35 with better resolution and a heavy reticle than a 9x40 built for sheer brightness with fine crosshairs.
 
According to Leupold rep, the only reason they make 50mm objectives is because"My grandad used a 50, my dad used a 50, so I'm gonna use a 50". With modern glass, a 50mm isn't necessary.
 
isn't necessary for what?

This pretty much sums it up. Even the most modern glass and coatings can't change physics of electromagnetic radiation (visible light) intensity multiplied by surface are (lens diameter). There's no such thing as 100% efficiency, much less 110 or 150%. Lens size matters.

Low light is a relative term. For some it means dusk when color perception begins to fade at around 5lm. That's when you can still see something even if your scope is one step up from a 1x45 toilet paper roll and cotton string crosshairs. To others it can be a few millilumens from faint reflection of artificial light from clouds and even fluorescence of vegetation - yes, rotting plants emit a minimal amount of light. 0.2lm of full moon is plenty if you have a decent scope.

When you've been limited by law to hunt only in daylight and maybe +/- an hour, you've never really experienced what low light can mean when taken to the extreme that's business as usual for hunters who have hunted legally at night all their lives. There's little anyone really "needs" for hunting. Iron sights on grandpa's .30-30 will do the trick, as proven time and time again, but anyone claiming that being able to see better in all situations isn't a good thing can only speak for himself. Well enough may suffice but better is... better. Always. No ifs or buts. And if I'm not mistaken, the subject of this thread was "Best low light scopes?" when I last checked.
 
When you've been limited by law to hunt only in daylight and maybe +/- an hour, you've never really experienced what low light can mean when taken to the extreme that's business as usual for hunters who have hunted legally at night all their lives. There's little anyone really "needs" for hunting. Iron sights on grandpa's .30-30 will do the trick, as proven time and time again, but anyone claiming that being able to see better in all situations isn't a good thing can only speak for himself. Well enough may suffice but better is... better. Always. No ifs or buts. And if I'm not mistaken, the subject of this thread was "Best low light scopes?" when I last checked.

I don't know of much true night time hunting done in the states that artificial lights aren't allowed.
 
I've got a Simmons whitetail classic 6.5-20x50 that is better in moonlight than my leupold vxII 3-9x40. Both less than 3 years old.
The leupold is certainly higher-quality and clearer but not as good in extreme low light.
 
I don't know of much true night time hunting done in the states that artificial lights aren't allowed.

Nor are they in most of Europe, hence the need for top quality optics to make the best of whatever little natural light is available.
 
while the OP is asking about hunting, keep in mind the demographics have changed and most people that shoot are no longer hunters and thus not subject to those restrictions.
i shoot at night all the time.
 
IOR/Valdada scopes with Schott glass and premium coatings give tremendous value for the money. A fixed 4x will work well for most hunting we do around here at less than half the price of a Swarovski in the same magnification.

I've also been impressed with some of the upper-end Konus Pro offerings.
 
It isn't the glass...

It is the coating. That is what dictates the light transmission abilities of any given lens.

That is among the most closely guarded industrial technology today.

Optical glass is pretty simple to make, and it is produced in many countries.

Why are the scopes from Germany or Austria more $$ and have the best light transmission today?

The same reason a Zeiss or Leica photo lens setup is more than a Nikon or Canon. The proprietary lens coatings other companies just cannot duplicate.

BTW, the larger the objective, the more light hits that coating, as mentioned previously.

DG
 
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