Rifle Scopes How do LPVOs perform in low light?

[Jayjay1]

Hey guys,
I´ve learned, that you have to have a big objective lens which catches as much light as possible to be able to have a sight picture as long as possible in low light conditions.

If this is true, LPVOs should be a pita in low light, correct?

Can you school me about this?

 

[JWG]

My NX8 does fine. I can even use it under NVDs with the Wilcox Raid Xe acting as illuminator, although it's rather dim on 8x. The thing with LPVO's, is you can dial to your lighting conditions. I find that 4-5x is best on the NX8 at night.

As I recall though, ACOGs are pretty much king at this sort of thing. I remember thinking my ACOG sucked up more light than my naked eye did.

 

[308pirate]

Hey guys,
I´ve learned, that you have to have a big objective lens which catches as much light as possible to be able to have a sight picture as long as possible in low light conditions.

If this is true, LPVOs should be a pita in low light, correct?

Can you school me about this?

Aren't you in Germany? If so there should be plenty of boar hunters to ask about exactly that.

 

[Jayjay1]

Aren't you in Germany? If so there should be plenty of boar hunters to ask about exactly that.

Yes, I am.
And on top of that, I´m a hunter myself since two years.
And even, we hadn´t boars the last two years, but now they came back and I found me sitting my ass flat at night at the corn fields.
But boar hunting is done with NV now, after it got legal some years ago.
And LPVOs are only used at driven hunts, if at all by hunting, there are mostly 3-12x50ish scopes used.

I´m partial just curious and want to learn about it and on the other hand I actually looking for an optic for a 18" AR15.
So, what makes a scope more or less bright?

 

[JWG]

Yes, I am.
And on top of that, I´m a hunter myself since two years.
And even, we hadn´t boars the last two years, but now they came back and I found me sitting my ass flat at night at the corn fields.
But boar hunting is done with NV now, after it got legal some years ago.
And LPVOs are only used at driven hunts, if at all by hunting, there are mostly 3-12x50ish scopes used.

I´m partial just curious and want to learn about it and on the other hand I actually looking for an optic for a 18" AR15.
So, what makes a scope more or less bright?

A lot has to do with optics coatings, as well as lens quality and how the magnification is managed (how many lenses) as well as light control within the optic. It's a complex AF answer. For example, my MK6 had a 20mm obj and my K16i had a 24mm obj. In low light, one did not stand out above the other, even though that's a nearly 20% difference in dia.

 

[Jayjay1]

A lot has to do with optics coatings, as well as lens quality and how the magnification is managed (how many lenses) as well as light control within the optic. It's a complex AF answer. For example, my MK6 had a 20mm obj and my K16i had a 24mm obj. In low light, one did not stand out above the other, even though that's a nearly 20% difference in dia.

And 44% more area.

 

[JWG]

And 44% more area.

I didn't want to do the math, but yeah...and none of that translated to an advantage that I could detect at dusk.

 

[hlee]

In general, divide magnification by objective lens diameter to get “exit pupil.” This is the diameter of the column of light exiting the scope, entering your eye. A human eye pupil can dilate to ~ 5 mm, so an exit pupil larger than that is overkill. A larger objective will give you a larger exit pupil at higher magnification.

Beyond that, light transmission is governed by the quality of the glass and lens coatings. Low quality glass/coatings with a large exit pupil may well appear dimmer than higher quality glass/coatings with a smaller exit pupil.

Then there is your own biology. Older eyes don’t work as efficiently as young eyes. What appears amazing to someone else may appear dim or cloudy to you.

 

[stanley_white]

If there was a 1-8x56mm I would buy it.

-Stan

 

[Jayjay1]

Well, one of the LPVOs I was interested in, is the Kahles K18i-2, but have now noticed, that those although their tube dia is 34mm, only do have a 24mm objective lens.

With 8x magnification this would mean an exit pupil of 3mm.
And that at a scope which costs (over here) 2.5k.

 

[db2000]

I’ve never understood why a scope like Razor G3 1-10 will have 34mm tube and 24mm objective lens. I believe there’s some difference due to outside tube diameter vs the inside lens diameter, but a full 10mm??
Doesn’t seem to add up to me.

 

[hlee]

Paging the Dark Lord of Optics; @koshkin please pick up the white courtesy phone…

Why don’t we see LPVOs with large diameter objectives?

 

[Niles Coyote]

A human eye pupil can dilate to ~ 7 mm, so an exit pupil larger than that is overkill. A larger objective will give you a larger exit pupil at higher magnification.

corrected, but without amphetamines or caffeine.

I have been using a Trijicon 1-8x and more often a couple Vortex 1-4x's (due to their lighter weight) the past few years. Most of my hunting is inside 100 yards and I like the wide field of view they have at around 2x. I have not had any issue identifying deer and their points within the legal hunting hours we are restricted too. That's 30 minutes before sunup and 30 minutes after sundown. In my thick wooded area, its significantly darker than out in the open field during those sundown phases.

Updated: I had initially mentioned the Nikon gold I'd use but forgot that it has a 42mm objective lens, so not a fair comparison.

 

[Makinchips208]

Paging the Dark Lord of Optics; @koshkin please pick up the white courtesy phone…

Why don’t we see LPVOs with large diameter objectives?

Hopefully he will chime in, but here is a video he did on the subject.

 

[db2000]

Hopefully he will chime in, but here is a video he did on the subject.

Well, there it is. Excellent as usual

 

[koshkin]

Paging the Dark Lord of Optics; @koshkin please pick up the white courtesy phone…

Why don’t we see LPVOs with large diameter objectives?

That video linked in a previous post should explain it. If it does not, I can go over it again in a livestream format with real time questions.

In a nutshell, because bumping up the objective diameter while maintaining 1x on the low end and good FOV and depth of fiels would make the scope absolutely enormous.

Vanguard does make a 1-7x44 riflescope. I saw it once at SHOT. It is not great, for fairly obvious reasons, but you can give it a shot https://alnk.to/bEiKqqt

I am sure some Youtuber already reviewed it and gave it a glorious review, but there is a reason companies that actually know how to use these products do not build this configuration.

ILya

 

[hlee]

That video linked in a previous post should explain it. If it does not, I can go over it again in a livestream format with real time questions.

In a nutshell, because bumping up the objective diameter while maintaining 1x on the low end and good FOV and depth of fiels would make the scope absolutely enormous.

Vanguard does make a 1-7x44 riflescope. I saw it once at SHOT. It is not great, for fairly obvious reasons, but you can give it a shot https://alnk.to/bEiKqqt

I am sure some Youtuber already reviewed it and gave it a glorious review, but there is a reason companies that actually know how to use these products do not build this configuration.

ILya

Nope, no need to rehash. That video is great.

 

[Burdy]

They don't perform well in low light at all. I can move from the best of the best in LPVO's to a 1.5-8x32 Razor and the low light performance increase is significant.