Best low light scopes?

[Cypress]

Just to confuse the matter further. I forgot to mention that I use a pair of fairly cheap $100 binocs to spot with at night. They are easily twice as bright as my $500 scope. Twice as much lense surface? Using both eyes? I don't know. What I do know is it's frustrating as heck when you can see a hog plain as day through the binos but can't see well enough to shoot with the scope. This is usually where the belly crawl to close the distance starts?

 

[hq]

Just to confuse the matter further. I forgot to mention that I use a pair of fairly cheap $100 binocs to spot with at night. They are easily twice as bright as my $500 scope.

I'd guess that you either have an unusually good binoculars or a scope that isn't optimized for maximum light transmission in low light. Or both.

I'd really like to know what make/model spotting binoculars you have? $100 binos with decent low light performance sounds great and I've been looking for a pair I could take to hunts where the risk of damaging Zeiss binoculars is a bit too high for what they'll cost to replace...

 

[coloradokevin]

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.

No, because you and I are talking about two different things here. The experiment that you mentioned (which we all surely did as children) merely convinces me that the magnifying glass focused the light that struck its large "objective" lens, and a concentrated beam of light then burned the object of our desires (usually ants when I was a kid).

Anyway, what I've repeatedly tried to explain here is that the myth that some small objective scopes are able to "gather" light because of some mystical and magical voodoo-like properties is entirely false. I've explained this a couple of times already, earlier in this thread. As I said then, some folks seem to be convinced that their "40mm light gathering scopes" are somehow capable of going out and "getting" more light than a comparable 56mm scope. That's simply untrue.

As I've also said repeatedly, I have no intention in getting lost in a jargon war here, I only intended to dispel one fairly persistent rumor that I keep hearing around here about "light gathering scopes".

Regardless, I guess we could use your magnifying glass example as a means of at least partially explaining my point. Consider this scenario:

If you take the magnifying glass and hold it so the sun shines through the lens, and hold it with the proper relief between the lens and the object upon which you are concentrating the light, we all know it will burn that object.

But, if you took that same magnifying glass and held it at a different angle, so that the sun wasn't directly shining on the lens, it would not have that effect.

Why? Because the magnifying glass is not able to go out and "gather" light in the way that I used the term. It only transmits the available light. More direct light = more light to concentrate.. Less direct light = less light to concentrate.

In that respect it does not "gather" light.

Now, admittedly, perhaps I used a poor choice in terms when I said that scopes do not "gather light". But, in the way that I explained it previously, that's an entirely accurate statement. If you mean to suggest that they can concentrate available light from the objective end of the scope to the ocular end of the scope, I'd obviously agree with you there (i.e.: a 56mm objective does not produce a 56mm exit pupil size).

It was more of a marketing/gun counter myth I was trying to dispel… some folks believe do believe that there are "regular" rifle scopes out there, and special "light gathering scopes". It makes a simple explanation of this stuff difficult, until we all get on the same wavelength about what actually matters when picking a scope for low light conditions. That's all I was getting at.

So, again, for low light conditions:

1) Pick a larger objective lens
2) Pick a lens with better glass and better coatings
3) Pick a scope with less magnification than another comparable scope

 

[Vern Humphrey]

The experiment that you mentioned (which we all surely did as children) merely convinces me that the magnifying glass focused the light that struck its large "objective" lens, and a concentrated beam of light then burned the object of our desires (usually ants when I was a kid).

That, by definition, is "gathering light."

Light (and heat) falling onto a large area is gathered and transmitted to a smaller area.

 

[coloradokevin]

Sigh. Whatever. This is becoming an argument of semantics at this point. I think I pretty clearly explained which myth I was trying to dispel. As with many things in language, terms and words can have more than one meaning, depending on usage.

Yes, scopes do concentrate (or "gather", if you prefer) the visible light that strikes the objective lens, and you view this light on the ocular lens side in a smaller form (exit pupil size).

Scopes do not go out and get more light in the way I've repeatedly described in this thread. If no one was under that illusion in the first place, this is a moot point. But, it's a rumor that seems to pop up from time-to-time around the places I frequent. Anyway, that's the only usage of the term "light gathering" that I was trying to address.

 

[Vern Humphrey]

Scopes do not go out and get more light

Whoever said that scopes GO out and get more light?

Scopes GATHER what falls on the objective lens and transmit it to the eye in a concentrated form.

 

[Walkalong]

I am in the "it lets it in" camp, vs gathers, but everyone agrees that the scope cannot "gather" or "let in" any more light than hits the lens, so a bigger lens has more light it can use. The rest is up to glass quality and coatings quality.

The question is how much can be used by the eyes. The experts say anything over around 5 to 7MM can not be used by the eyes because of the pupil size. Just like a scope objective, the eye can only use what can enter the pupil. (Gather/Let in)

So, we must take magnification into account. A 50 MM objective at 10 power has a 5MM exit pupil. The eye can use all of that and maybe more. A 40 MM objective at 10 power has a 4MM exit pupil. Our eye can use more than that, so we are limiting ourselves. A 40 MM objective at 6 power has a 6.6MM exit pupil. Much better. The 50 at 8X is 6.25 MM so the larger objective lets us use a higher magnification.

We can adjust the power down to get as big an exit pupil as our eye can use, so the objective size doesn't hurt us there. It does hurt us in how much magnification we can use.

So, if we dial the scope to a magnification that gives us the max exit pupil our eye can use, does the objective size matter? Assuming identical glass and coatings, is the 50MM objective at 7MM exit pupil brighter than the 40 MM objective at 7MM exit pupil? Or it it wasted because our eye simply cannot use it? It sounds like the engineer at Schmidt and Bender thinks it is.

 

[coloradokevin]

Vern, apparently you didn't read my other posts in this thread. I've already described at least one conversation I had with a shooter who believed that some scopes go out and "gather light". And, I've heard that misconception repeated a number of times at local gun shops / ranges. Maybe it's a regional thing?

But, if we're going to continue to debate the vernacular here, it's important to recognize that "gather" is a verb. The behavior of a scope is entirely passive, at least as far as this aspect is concerned. As such, I think some folks have the mistaken impression that some "special" scopes actually have a design that allows them to actively bring in more light than their optical design would otherwise transmit (see the quote I added from another shooter earlier in this thread). I don't know why some folks have felt this way, though I suspect marketing and ignorant gun store employees play a part. Anyway, I only mentioned this because I've heard it on a number of occasions during gun store debates about optics, and because the opening post mentioned a "light gathering" scope.

So, in an attempt to aid the OP, I was wanting to make sure that he understood the basic design criteria he should consider when trying to identify a good scope for his purposes.


(Never realized the can of worms I was opening!)

 

[Haxby]

Assuming identical glass and coatings, is the 50MM objective at 7MM exit pupil brighter than the 40 MM objective at 7MM exit pupil?

Yes, it is.
There is a greater density of light energy. A greater number of photons per square millimeter. A greater amount of light, from the larger objective, focused on an equal-sized area at the exit pupil.

 

[Walkalong]

OK, sounds reasonable. So, is it enough difference that the eye can "see" it? Does it actually make the image appear "brighter/clearer" when used at dusk or dark?

I would love to have two identical scopes, except for the objective size to compare.

The only scopes I have with an objective larger than 44MM are not used for hunting or shooting at dusk/dark.

I have (Well, now my son has) a Bushnell 4200 3X9-40 (I think it's 40) that is very "bright" at dusk, and my Leupold that is 36MM and it also does very well. I guess I need to buy a nice scope with a 50MM objective and try it out.

 

[taliv]

So, if we dial the scope to a magnification that gives us the max exit pupil our eye can use, does the objective size matter?

yes

Assuming identical glass and coatings, is the 50MM objective at 7MM exit pupil brighter than the 40 MM objective at 7MM exit pupil?

yes

Or it it wasted because our eye simply cannot use it?

this is the difference in theoretical and the real world. real world, your eye is often not perfectly aligned so larger exit pupil would be slightly more forgiving

It sounds like the engineer at Schmidt and Bender thinks it is.

sounds like something was lost in translation

 

[rogn]

Bright is bright but resolution is still the answer. You can have lots of "gathered light", but if the colors are not meeting at the edges of objects you just have a blur. So good quality lenses ground for good resolution are what can make the scope useful.

 

[Haxby]

To demonstrate this, you don't have to have 2 identical scopes, and you don't have to have a 50mm scope. Take 2 comparable scopes with different sized objectives, and see which will provide a useful image the longest after sunset. This will be dependent on local conditions, and your eye will have to be adapted to the dark. Go back and forth between a 20mm and a 32mm scope, or a 32 and a 40. Adjust the magnifications up and down on both scopes to see what exit pupil works best for your eye as the daylight decreases.

It sounds like the guy from Schmidt and Bender was saying the important thing was to buy a Schmidt and Bender.

 

[jrdolall]

I hunt deer in the hardwood bottoms of Alabama and Georgia for the most part. I can tell you that there is a great deal of difference between the light "gathering/transmission/admission" of a 50 mm scope and a 40 mm scope. I have limited knowledge of physics or coatings or any other scientific thingamabobs. I do not own a 56mm so I can't speak to them but a medium priced scope, Leupold and Nikon for sure, the difference is noticeable during those last few minutes of shooting light.
As far as binoculars are concerned, I have a $1500 pair of Leica binoculars that are wonderful for glassing the prairie and fields but I use a pair of Bushnell Perma-Focus binos for most of my deer hunting. $75 binos that have excellent light "gathering" abilities for my application. I have no idea how they work as they do not require focusing but they do work.

 

[hq]

(Never realized the can of worms I was opening!)

Yep. I've seen something like this happen a few times. That's why I prefer to start with simple physics because that's where the conversation will eventually be heading. Or, to make things very simple, just recommend the Zeiss and Swarovski 56mm scopes I did early on in this thread, because they're pretty much the definitive low light scopes this side of night vision and thermal imaging.

Then again, thermal scopes are legal for hunting around here, mainly because of a loophole caused by the choice of words in hunting legislation, so there's a good reason why I've skipped the usual Zeiss on one of my rifles and placed an order for Pulsar Apex XD-series thermal. Pretty much the ultimate choice for low light (and no light) hunting...

 

[Lloyd Smale]

to be fair you do have to take two indentical model scopes from the same manufacturer one with a 40 and one with a 50 and compare them. You cant compare a leupold 50mm aginst a tasco 40. Ill add this if you compare two scopes like tascos or bottom line bushnells your going to see a greater increase in light transmition with a 50 over a 40 then you will with something like two vx3 leupolds doing the same and then step up to top line ziess swarovskis or kahles ect and the light transmition of a 40 is so good at that level that id bet theres really not a set of eyes on the planet that can tell the diffence between a 40mm and a 50mm except maybe in the middle of the night with no moon. Id bet my last dollar that a 4omm kahles or ziess is going to do better in low light then a tasco would with an objective the size of a 55 gallon drum. Lenses and coating quality is where its at not size

 

[Vern Humphrey]

I've already described at least one conversation I had with a shooter who believed that some scopes go out and "gather light".

What's this "go out" business? Did anyone EVER say the lens leaves the objective bell and goes looking for light?

The objective lens gathers the light that falls on its surface and concentrates it -- resulting in more light reaching the eye than the eye would receive naked.

 

[redneck2]

I think you guys are trying to say the same thing in different ways..

It seems obvious that a scope concentrates light. You have 40mm worth going into the front end being squished down to, say, 7mm. Terminology is getting in the way

That said, this thread is interesting so please keep it civil so it stays open

Thx

 

[coloradokevin]

What's this "go out" business? Did anyone EVER say the lens leaves the objective bell and goes looking for light?

Basically, yes, that is what they've suggested, though they didn't see it in the way you just described. There are some shooters who believe that (all else being equal) a 40mm objective lens can "collect", "gather", or otherwise "find" more light than a 56mm lens, just so long as you are using a "light gathering scope". Because, in the opinion of the folks who seem to persist in defending such an argument, some scopes are designed to 'bring in other light'.

Again, I've had the conversation with shooters who have given me the: "this is a light gathering scope" argument as a means of defending their belief that a 40mm objective lens is somehow superior to a 56mm lens (again, all else being equal).

Obviously this is not my belief, as I posted that information with the sole intention of trying to dispel such rumor.

Honestly, I'm not sure how much more clear I can make that particular point. Clearly you already understand the basics here. The same can't be said for others that I've spoken with in the past. But, as far as you and I are concerned, we seem to only be discussing jargon and vernacular at this point (as we already agree on the science of how this works).

The objective lens gathers the light that falls on its surface and concentrates it -- resulting in more light reaching the eye than the eye would receive naked.

And, by that definition of "gathering light", I've never disagreed with you.

I have, however, disagreed with the premise that some "special" lenses can "gather" more light than their objective size would otherwise allow for (NOTE: I know this is not what you are saying — however, others have said that to me, as previously described).

For instance: the 50mm objective lens on my S&B will not be able to take in as much light as a 56mm objective lens on another S&B. How much actually reaches the eye is a function of some other factors as well, but from the very outset the 56mm lens will allow more light through than a 50mm lens.

The rest of the conversation concerns the other design parameters that have been included in this thread: glass quality, coatings, magnification, exit pupil size, etc. Surely there are some other subtle design qualities that also impact a scope's ability to perform in low light, but again, I'm no engineer.

It seems obvious that a scope concentrates light. You have 40mm worth going into the front end being squished down to, say, 7mm. Terminology is getting in the way

I agree.

That said, this thread is interesting so please keep it civil so it stays open

I don't see this thread losing its civility. We might create a whole new language for the industry before we're done, but we'll get there eventually

 

[Vern Humphrey]

Basically, yes, that is what they've suggested, though they didn't see it in the way you just described. There are some shooters who believe that (all else being equal) a 40mm objective lens can "collect", "gather", or otherwise "find" more light than a 56mm lens,

But no one involved in this discussion has made such a claim. Please do not accuse us of saying things we did not say.

We have pointed out that a scope with a large objective lens gathers and transmits most of the light that falls on its surface to the ocular lens, thus providing the eye with more light that it could otherwise get.

 

[redneck2]

Vern......dude...he didn't say here. He didn't say you. He said

There are some shooters who believe that (all else being equal) a 40mm objective lens can "collect", "gather", or otherwise "find" more light than a 56mm lens,

Don't take it personally

Now, anyone who (all things being equal) thinks a 40 mm would transmit more light than a 56mm is delusional

Now, I worked at the LGS. If you think there's no such things as a stupid opinion, work there for a week and you'll change your mind.

 

[Vern Humphrey]

Is it taking it personally to point out that no one on this thread said they "believe that (all else being equal) a 40mm objective lens can "collect", "gather", or otherwise "find" more light than a 56mm lens?"

 

[d2wing]

As Redneck said, a lens concentrates light. Pay attention. The larger the lens, the more light strikes it. Whatever that light is, it is focused to the exit pupil. A larger lens is said to gather more light because the amount of light striking it is greater therefor brighter when concentrated. The size lens does matter. Incoming light is not wasted. The quality of glass coatings and precise focusing is essential to maximum performance. The quality being equal, the larger objective will gather and focus more light. Don't be silly about the term gathering. More air goes through a big door than a small one. More light goes through a large lens than a small one. That is more light to concentrate to the eye therefor brighter. hQ knows exactly what he is talking about.
If you look through a cheap,scope and a good one the same size at night you will see quality matters. And looking through different size scopes at night and you will also see size matters. Especially at higher magnifications. I have seen scopes so bad that you can't see through them at high magnification in daylight. GAMO for example.
Anyway with a very good scope with a large objective you will be able to better in very low light than you can with the naked eye because the light is concentrated. Got it? I can't type any slower.

 

[DM~]

I'll cut to the chase... I've spent HUGE amounts of time (two different times) and some money trying to find the absolute BEST low light level scope for an "affordable" price.

After all the scope comparing, I bought Zeiss Conquest both times! In lower to low light, they out performed every other scope anywhere near their price...and many costing a lot more!

BTW, I did the comparing out in the field, NOT inside a store...

DM

 

[cdb1]

All I know is this. My best low light scopes are in order:
Meopta MeoPro 3.5-10x44
Zeiss Conquest 3-9x40
Bushnell Elite 4200 3-9x40
Leupold VX-3 1.75-6x32
Leupold VX-R 2-7x32
All but the VX-R have 1" tubes.
Your eyes may vary.