Rifle Scopes S&B 5-25 vs 3-20 US at 20x

[carbonbased]

Ok S&B wizards, I own a 5-25 with the H2MCR but am considering replacing it.

Have my eye on either the same scope or 3-20 US with the GR2ID (in case this scope lands on my 204 someday, the TR2ID doesn’t fit my varmint shooting 204-blowing-in-the-wind needs).

My question to you is at 20x, give me your feels on both. Eyebox, sharpness, etc. 20x is where I shoot a LOT at due to tiny targets. Way smaller than a typical CF comp steel plate and 20x magnification is critical. For me, anyway.

Above 20x mirage is often a factor, so 20x is the sweet spot. And on the gun I’m thinking about, a S&B is a perfect look.

I do know a scope tends to perform the best in the middle mags, or at least not in the extremes of its mag range. The 5-25 does darken rather significantly between 20x and 25x, and that’s another consideration if that happens to the 3-20 at 20x.

So I can guess at what the crowd will say, but I’d like to hear from those who have looked through both models.

 

[Bakwa]

5-20 US is the way.

 

[carbonbased]

5-20 US is the way.

Doesn’t appear to come with the GR2ID…unless one orders it custom. Also, in cost it tends to be on the high side…obviously must be one of their more popular models.

 

[Huskydriver]

Aight so I have owned at one point or another most of the main pm ii scopes.

I love the 520 us have several currently and it's one of my fav all times scopes....However, I have yet to see one that out performs a 525 in image quality any day of the week so there's that.

The 320 us imo isnt a whole lot better in the 2 I have owned vs the 520us. I honestly have a hard time even suggesting the 320 us because it's got so many tradeoffs imo you are better off running a 520us if length is your constraint, or a full size 525 or bigger.

The regular plain full length 320 pmii has arguably one of the better SB image quality of the old lines but it is long discontinued. I believe you can special order one tho... For like 8k shipped lol..

Which brings me to the ole trusty 525.... I still got a couple and tbh.... At used market 2-2800 USD depending on configuration.... Is still a great buy imo. If you are running like 50 moa offset sure I can see some dimming at 25x but your also not anywhere near optical center for a 20 yo design. I typically run 30 moa and don't see a degradation at 25x however.... I also don't typically shoot at 25x like ever.... Maybe zoom in to check group size but def not when it matters on the clock or what have you.

Bigger question to you is why are you looking at SB at all? Why do you need a tree to shoot in the wind? Pick your reticle and then go from there.

 

[dms416]

As with most scopes, the worst power is max power. The 3-20 US at 20x is pushing the optical limits and feels as such. It's usable, but if I were set on using 20x, I would want something that has a 25x top end.

I no longer have any US's (despite having 6 or 7 in total over time). The ZCO420 blows it out of the water in almost every area save for adding a few ounces and having to get a 36mm ring/mount. However, it's worth it IMHO.

 

[carbonbased]

Bigger question to you is why are you looking at SB at all? Why do you need a tree to shoot in the wind? Pick your reticle and then go from there.

So, why S&B? Why not ZCO or etc
Basically because vanity. S&B’s just looks right on an AIAT lol. In particular, I really like the look and function of their illumination control (“tumor” the plebs call it, sniff sniff). It’s not quite a clone thing, but you get the drift.

Why a tree?
Because, for me, I found using a tree for elevation and wind holds is waaay faster than dialing when shooting at long strings of successive pdog waves overwhelming my “position” lol

I bought the 5-25 S&B with the H2MCR to attempt to see if I like dialing. I’ve not yet totally made a final decision, but it sure feels like I want to got back to a tree. But it is easier to see misses, and I use the AT for mainly the over 450yds shots…counterintuitively, high mag is more import for the closer stuff like people discover in 22LR comps.

And changing the reticle to the gr2id costs $1430 in the 5-25 as of this time last year, so it sorta makes more financial sense to sell the scope and buy the S&B with the tree. If I do indeed switch, that is.

If you are running like 50 moa offset sure I can see some dimming at 25x but your also not anywhere near optical center for a 20 yo design. I typically run 30 moa and don't see a degradation at 25x however.... I also don't typically shoot at 25x like ever.... Maybe zoom in to check group size but def not when it matters on the clock or what have you.

The scope is on the typical 20moa AI rail and zeroed at 100yds, so it’s pretty close to optical center. I notice the dimming as I’m usually at 20x to 25x all day except when refinding a pdog tha I found in binos.

It’s not horrible, but it’s worse than the Razor G2 I have. And I was a little bummed that it dimmed at all, given the cost and pedigree. But…I then remind myself of how old the design is and how advanced it was, and give it a pass.

Normally I don’t consider the look of the scope so much, but for this one rifle, well, I’ve decided I can do that.

Looks are the main reason that it’s hard to put a 6-36 S&B atop the AT…which is the rational choice. No separate tumor illumination control and that weird nipple focus knob thing lol wtf were the industrial designers thinking?

Anyway, suspicions confirmed that the 3-20 US may be a lateral step at the very best, and probably a step backwards from the 5-25 that I have.

 

[Malum Prohibitum]

How old are you? Hoe many Korean vets are still around?

 

[JER6.5]

Since you bring up the 6-36, It is a way better scope than the 3-20 and the 5-25, not even comparable. The 3-20 and the 5-25 sits on the shelf and 6-36’s have replaced them.

To be noted, some failures on 6-36 have been reported on higher recoiling guns. I have not had issues on my 3 scopes, 338LM being the biggest cal.

 

[Kiba]

It's too bad they discontinued the full length 3-20 because it's a very good scope, quite a bit better than the ultrashort that replaced it IMO when it comes to eyebox, dof, and image quality. One of my favorite scopes. Very usable mag range, huge fov on 3x and good AFOV, very good glass across the entire mag range, and not ridiculously heavy. I have 3 of them, and even though only one is mounted to a rifle at the moment (my sako quad .17hmr that's used for 200y and in ground squirrel blasting) I can't bring myself to sell the other 2 knowing I can't easily replace them... so they sit in the safe until I find something to put them on.

Regarding your current 5-25 compared to the 3-20US, give me the 5-25 any time unless you absolutely need the low base mag or short length of the 3-20US to use with a clip on. When it comes to the ultrashorts I prefer the 5-20 to the 3-20, but I prefer the full length scopes over the ultrashorts.

Unfortunately even if you found a 3-20 non-US the reticle choices aren't what you have in mind. I think the offerings were P4FL, H2CMR, possibly MSR, and the only tree style offerings were a couple of tremors (gross, lol.)

If you wanted to keep the AI / S&B 5-25 classic look, you could get a new 5-25 with the gr2id reticle, but that makes zero financial sense when the new and much improved 6-36 would be almost the same price... The 6-36 doesn't have the classic 5-25 cosmetics though, so you'll need to decide what you want.

The 5-25, while getting old, is still a good scope. I started buying them off the PX here back around 2011 and have several of them, and every time I think about selling them to upgrade to something newer I realize even when I shoot them back to back with my Tangents they are not holding me back in any way and still provide a very nice image and work perfectly. At new S&B prices I'd never go with a new 5-25 over a new 6-36, but for $2300ish for a used 5-25 that's an entirely different price category.

 

[Glassaholic]

It's too bad they discontinued the full length 3-20 because it's a very good scope, quite a bit better than the ultrashort that replaced it IMO when it comes to eyebox, dof, and image quality. One of my favorite scopes. Very usable mag range, huge fov on 3x and good AFOV, very good glass across the entire mag range, and not ridiculously heavy. I have 3 of them, and even though only one is mounted to a rifle at the moment (my sako quad .17hmr that's used for 200y and in ground squirrel blasting) I can't bring myself to sell the other 2 knowing I can't easily replace them... so they sit in the safe until I find something to put them on.

Regarding your current 5-25 compared to the 3-20US, give me the 5-25 any time unless you absolutely need the low base mag or short length of the 3-20US to use with a clip on. When it comes to the ultrashorts I prefer the 5-20 to the 3-20, but I prefer the full length scopes over the ultrashorts.

Unfortunately even if you found a 3-20 non-US the reticle choices aren't what you have in mind. I think the offerings were P4FL, H2CMR, possibly MSR, and the only tree style offerings were a couple of tremors (gross, lol.)

If you wanted to keep the AI / S&B 5-25 classic look, you could get a new 5-25 with the gr2id reticle, but that makes zero financial sense when the new and much improved 6-36 would be almost the same price... The 6-36 doesn't have the classic 5-25 cosmetics though, so you'll need to decide what you want.

The 5-25, while getting old, is still a good scope. I started buying them off the PX here back around 2011 and have several of them, and every time I think about selling them to upgrade to something newer I realize even when I shoot them back to back with my Tangents they are not holding me back in any way and still provide a very nice image and work perfectly. At new S&B prices I'd never go with a new 5-25 over a new 6-36, but for $2300ish for a used 5-25 that's an entirely different price category.

Kiba and I are on the same page here ^^^

I have had multiple 3-20 ultra shorts and one 3-20 non ultra short and a couple 5-20 ultra shorts. Of all three, the 3-20 non ultra short (NUS) has the best 20x performance, next is the 5-20 US with the 3-20 US trailing. I think of the 3-20 ultra short as a fantastic 3-18 that goes up to 20x for PID (albeit with slightly less contrast and clarity), but I'd rather keep it under 20x for better optical performance. Keep in mind this is comparing to other alpha glass, the 20x in the 3-20x is better than a lot of lesser glass and there are no issues using it at 20x other than what's mentioned above.

 

[wooferocau]

Ok S&B wizards, I own a 5-25 with the H2MCR but am considering replacing it.

Have my eye on either the same scope or 3-20 US with the GR2ID (in case this scope lands on my 204 someday, the TR2ID doesn’t fit my varmint shooting 204-blowing-in-the-wind needs).

My question to you is at 20x, give me your feels on both. Eyebox, sharpness, etc. 20x is where I shoot a LOT at due to tiny targets. Way smaller than a typical CF comp steel plate and 20x magnification is critical. For me, anyway.

Above 20x mirage is often a factor, so 20x is the sweet spot. And on the gun I’m thinking about, a S&B is a perfect look.

I do know a scope tends to perform the best in the middle mags, or at least not in the extremes of its mag range. The 5-25 does darken rather significantly between 20x and 25x, and that’s another consideration if that happens to the 3-20 at 20x.

So I can guess at what the crowd will say, but I’d like to hear from those who have looked through both models.

The 5-20 US is my LEAST favourite S&B "Opticaly" .... It can be quite "milky, hazy at times....its reasonably sharp but glass wise i think its S&B,s 2nd worst scope ( just edging out the 3-27) optically.

My dealer here in Aus got NEW stock of the current 5-25 PM2 revision...he is stunned how good it is! ! Its a far cry from the previous 5-25 of old.

 

[FUNCTIONAL]

Love my 3-20 non us with a tremor2 (wish it was a t3 though). If you can find a used one with a reticle you like it would be money well spent. I've seen a few pop up for the 2.1-2.6k range. From the sound of your use a tremor would be perfect, I'm not sure why the hate for then is there. Only thing I hate is the damn added fee for any horus

 

[Kiba]

Love my 3-20 non us with a tremor2 (wish it was a t3 though). If you can find a used one with a reticle you like it would be money well spent. I've seen a few pop up for the 2.1-2.6k range. From the sound of your use a tremor would be perfect, I'm not sure why the hate for then is there. Only thing I hate is the damn added fee for any horus

Can't speak for the OP, but for me the tremors are just way too cluttered with too many lines and dots for small varmint hunting, too easy for a target or miss splash to be obscured by the reticle, especially the T3 with those big solid circles. Granted, I've only looked though a couple of them, but very quickly decided they weren't to my liking and use case.

 

[carbonbased]

How old are you? Hoe many Korean vets are still around?

Mid-fifties and I apologize if I have offended with my rather crass joke of pdog waves attacking me.

 

[carbonbased]

How old are you? Hoe many Korean vets are still around?

Deleted the joke. Again, apologies.

 

[carbonbased]

Can't speak for the OP, but for me the tremors are just way too cluttered with too many lines and dots for small varmint hunting, too easy for a target or miss splash to be obscured by the reticle, especially the T3 with those big solid circles. Granted, I've only looked though a couple of them, but very quickly decided they weren't to my liking and use case.

I agree. Never looked through one but was thinking about buying one after a couple of esteemed military members here said that they improved their times in target simulations on the range. One fellow had really intensely hated the T3, but after doing the simulations enough times he ate crow and said the T3 had helped a lot.

So after I read that, I thought long and hard about the T3. One day I stopped theorizing in my fool head and decided to do some simple back of the napkin calcs. I found that a 4” kill zone on a pdog is about .3mils at 400yds.

And I estimate the big dots on a T3 are about .2mils in diameter and thus cover up a ~3” diameter circle at 400yds.

So after 400yds the big dots rapidly start to obscure an awful lot of a pdog (who may not stand tall but face you on all fours).

Here’s a chart I made a while back:

How much view does the 0.2 mil T3 big dot block?

RANGE​	MORE PRECISE​	ROUGH EST.​
100	0.72”	3/4”
200	1.44”	1.5”
300	2.16”	2”
400	2.88”	3”
500	3.60”	3.5”
600	4.32”	4.25”
700	5.04”	5”
800	5.76”	5.75”
900	6.48”	6.5”
1000	7.20”	7.25”
1100	7.92”	8”

(accuracy confirmed by @Jack Master)

So, for small varmints out a ways, a T3 or T5 isn’t great. And for this gun, a 6br, I sort of start shooting pdogs with it around 400-450yds, so a T3 isn’t ideal.

I typically use a 204 out to 400yds (450yds typical max, a couple walk-it-in shots at 510yds).

Original post with more info

Simple Weather, Ranging, Ballistics Solution

I am looking for a reasonable all round solution for the above. Currently I hunt mostly with my dad or friends. Our normal solution is a decent rangefinder and rifles with written down dope and thumb suck wind. Generally we would re-confirm it in the mornings if there's a range or something...

www.snipershide.com

 

[carbonbased]

Anyway, you guys are great. It’s like attending an Optics Anonymous meeting.

“Hi I’m carbon and I have a reticle, magnification, and scope aesthetics problem…”

A safe place to confess one’s optic obsessions…is always a good thing lol

 

[ejg]

I am using a 3-20 US P4Lfine as my main hunting scope since a few years, still is my favourite and most shots at longer range deer are on 20 mag. Only shot to 1200m max so far and got on very well. I also have a 5-25 with Grid2 but think the extra weight and extra size doesn't give any extra performance. Actually I often need the 3 mag when calling in stags in cover or walking through bushy areas to flush out deer. I looked through a 5-20 at a S&B stand which was very disappointing, maybe it was just a bad one.
Initially I had issues with the 3-20 until I took more time to adjust the Dioptrien until it suited all round. Also have a 3-27 and 4-16 PMII but think the 3-20 US is fantastic.

edi

 

[Kiba]

I am using a 3-20 US P4Lfine as my main hunting scope since a few years, still is my favourite and most shots at longer range deer are on 20 mag. Only shot to 1200m max so far and got on very well. I also have a 5-25 with Grid2 but think the extra weight and extra size doesn't give any extra performance. Actually I often need the 3 mag when calling in stags in cover or walking through bushy areas to flush out deer. I looked through a 5-20 at a S&B stand which was very disappointing, maybe it was just a bad one.
Initially I had issues with the 3-20 until I took more time to adjust the Dioptrien until it suited all round. Also have a 3-27 and 4-16 PMII but think the 3-20 US is fantastic.

edi

Agreed, the 3-20 is an excellent hunting / crossover scope, the FOV and mag range really hits a sweet spot. My 2x 3-20s that aren't currently being used may get installed on my 2x lightweight hunting rifles even though they will add about 11 ounces over the 4.5-22 LHTs that are currently on the rifles. The LHTs are great for what they are when weight savings is the primary goal, but the glass quality isn't up to par with the 3-20 full lengths, the 3-20s have a huge advantage in FOV especially at the bottom end of the magnification, as well as much better turrets.

Biggest gripe I have with my 3-20s vs 5-25s (both H2CMR reticle) is the reticle in the 3-20 is much thicker than the 5-25 and is less suited for small varmints and very small targets, but the 3-20 needs a thicker reticle so it doesn't disappear on 3x; a necessary compromise for the 6.67x mag ratio.

 

[carbonbased]

Agreed, the 3-20 is an excellent hunting / crossover scope, the FOV and mag range really hits a sweet spot. My 2x 3-20s that aren't currently being used may get installed on my 2x lightweight hunting rifles even though they will add about 11 ounces over the 4.5-22 LHTs that are currently on the rifles. The LHTs are great for what they are when weight savings is the primary goal, but the glass quality isn't up to par with the 3-20 full lengths, the 3-20s have a huge advantage in FOV especially at the bottom end of the magnification, as well as much better turrets.

Biggest gripe I have with my 3-20s vs 5-25s (both H2CMR reticle) is the reticle in the 3-20 is much thicker than the 5-25 and is less suited for small varmints and very small targets, but the 3-20 needs a thicker reticle so it doesn't disappear on 3x; a necessary compromise for the 6.67x mag ratio.

Are you still exclusively referencing the non-US 3-20? @ejg likes the US version.

 

[Kiba]

Are you still exclusively referencing the non-US 3-20? @ejg likes the US version.

I'm talking about the full length 3-20 because that's what I have several of.

I've looked though a 3-20 US and found it gave up some image quality, eyebox friendliness, and dof forgiveness compared to the full length 3-20. The 5-20US I looked through on the same day was a bit better than the 3-20US, but both fell short of the 3-20 full length. None were glaringly bad IMO, but my friend and I both agreed the ranking order was 3-20 full length > 5-20 US > 3-20 US. Usual disclaimers apply about limited sample sizes and everyone's eyes being a bit different.

The main advantages to the 3-20US over the full length are it's still available, you can get the latest turrets on it, and it's better suited for clip on night vision use because of the reduced length, but IMO optical performance of the US falls short of the full length version.

If S&B brought back the full length 3-20 and offered it with the tr2id and gr2id reticles and the DTII+ turrets, that would be an awesome scope...

 

[ejg]

Only ever spent ten minutes comparing 3-20 to 3-20US. Thought they were very similar then.
Recently spent a day out comparing the new S&B Meta 3-18x42 with the 3-20 US. Meta seemed very good in comparison until this situation with a bit of glare and moist air. The 3-20seemed quite a bit clearer & less glare.

just checked, I have that 3-20US since 2016 so really got used to it..
edi

 

[Huskydriver]

Anyway, you guys are great. It’s like attending an Optics Anonymous meeting.

“Hi I’m carbon and I have a reticle, magnification, and scope aesthetics problem…”

A safe place to confess one’s optic obsessions…is always a good thing lol

Like straight up I have issues here lol

 

[TheOE800]

Like straight up I have issues here lol

I’ll bring the shitty coffee if you bring the donuts.

 

[Jack Master]

I do know a scope tends to perform the best in the middle mags, or at least not in the extremes of its mag range. The 5-25 does darken rather significantly between 20x and 25x, and that’s another consideration if that happens to the 3-20 at 20x.

Carbon - Since you tagged me above I'll give my 2c on this... (plus 200c more since it got long winded)
It looks like you want to know if the other scopes will get darker at 20x because its on the upper end of the power. This is what I'll address.

Why does the image get darker at higher magnification?
When we zoom in at the higher magnifications the image appears to get darker. This is not a failure of the scope and glass but this is a failure of our eye and our brain processing the light it sees. As we increase the magnification the beam of light (exit Pupil) of optics gets smaller. When the diameter of this beam of light get smaller than the pupil of our eye, extra light is let into your pupil. You brain has to process this extra light in the image and it makes the scope image look darker.

Example of this. Take a picture (no flash) of someone standing in front of a window. If the window is smaller than the the person and they block all the light coming in the window we can see the person well. (exit pupil larger than your pupil, no extra light gets in). If the window is larger than the person and light comes in around them and in the picture (no flash) we see a very dark image of the person because the background light if changing how the camera processes the light. (exit pupil smaller then our pupil and extra light gets in)

Calculate your Pupil Size.
We can figure out if another scope will be bright or dim by calculating the size of our pupil and compare it to the exit pupil of another scope.

Pupil size is calculated by dividing the objective diameter by the magnification (Dia./Mag) Example: 56mm Obj / 25x is an exit pupil of 2.24MM

We can figure out our pupil size by using our current scopes. If at 20x the image is nice and bright, 21x is still pretty good, and at 22x the image is starting to grey or fuzzy, we can back calculate to get our pupil size. 56/20=2.8mm(bright) 56/21= 2.66mm(good) or 56/22=2.54mm(grey). We would need al least a 2.66mm or larger exit pupil for us to see a clear, good, image.

Things to Note - The size of our eye's pupil changes and is effected my several things.
The more ambient light, the more we will automatically restrict our pupil size. On sunny days our eyes constrict to make the pupil smaller, on cloudy days our pupil opens more, at dusk our eye start to open even further to let more light in. In the dark our pupil is wide open to help us see in the dark the best we can. (When the room goes dark we say "I'm letting my eyes adjust". This is the pupil changing)
Age - the older we get the harder it if for our eye to constrict the pupil size.
For these reason try to do test your pupil size under the conditions you will be using the optics the most.

Will the New Scope have a darker image at 20x?
Now that we know the limit of our eye's pupil (2.66mm) for a good image we can calculate the exit pupil of the new scope at to see how it will work for us.
A 5-20x50 scope will have an exit pulip of 2.5mm at 20x. This is smaller than the 2.66 we need and the image will be darker. With this 5-20x50 the exit pupil will be 2.66mm on 18.8 power (50mm/2.66mm = 18.78) We'll be able to see clearly until 18.8power but the image will be darker at above this value.

Final Thoughts
The scope's image does not get darker because of the scope mechanics or glass quality. It gets darker because our eye and brain have to process more light information. Don't blame a scope for a dark crappy image on max magnification, its the human procces making the error.
Don't use high magnifications in darker conditions, our pupil is getting bigger so we need more light out of the optics to cover our pupil.

I hope this helps, have a good day.

 

[carbonbased]

Carbon - Since you tagged me above I'll give my 2c on this... (plus 200c more since it got long winded)
It looks like you want to know if the other scopes will get darker at 20x because its on the upper end of the power. This is what I'll address.

Why does the image get darker at higher magnification?
When we zoom in at the higher magnifications the image appears to get darker. This is not a failure of the scope and glass but this is a failure of our eye and our brain processing the light it sees. As we increase the magnification the beam of light (exit Pupil) of optics gets smaller. When the diameter of this beam of light get smaller than the pupil of our eye, extra light is let into your pupil. You brain has to process this extra light in the image and it makes the scope image look darker.

Example of this. Take a picture (no flash) of someone standing in front of a window. If the window is smaller than the the person and they block all the light coming in the window we can see the person well. (exit pupil larger than your pupil, no extra light gets in). If the window is larger than the person and light comes in around them and in the picture (no flash) we see a very dark image of the person because the background light if changing how the camera processes the light. (exit pupil smaller then our pupil and extra light gets in)

Calculate your Pupil Size.
We can figure out if another scope will be bright or dim by calculating the size of our pupil and compare it to the exit pupil of another scope.

Pupil size is calculated by dividing the objective diameter by the magnification (Dia./Mag) Example: 56mm Obj / 25x is an exit pupil of 2.24MM

We can figure out our pupil size by using our current scopes. If at 20x the image is nice and bright, 21x is still pretty good, and at 22x the image is starting to grey or fuzzy, we can back calculate to get our pupil size. 56/20=2.8mm(bright) 56/21= 2.66mm(good) or 56/22=2.54mm(grey). We would need al least a 2.66mm or larger exit pupil for us to see a clear, good, image.

Things to Note - The size of our eye's pupil changes and is effected my several things.
The more ambient light, the more we will automatically restrict our pupil size. On sunny days our eyes constrict to make the pupil smaller, on cloudy days our pupil opens more, at dusk our eye start to open even further to let more light in. In the dark our pupil is wide open to help us see in the dark the best we can. (When the room goes dark we say "I'm letting my eyes adjust". This is the pupil changing)
Age - the older we get the harder it if for our eye to constrict the pupil size.
For these reason try to do test your pupil size under the conditions you will be using the optics the most.

Will the New Scope have a darker image at 20x?
Now that we know the limit of our eye's pupil (2.66mm) for a good image we can calculate the exit pupil of the new scope at to see how it will work for us.
A 5-20x50 scope will have an exit pulip of 2.5mm at 20x. This is smaller than the 2.66 we need and the image will be darker. With this 5-20x50 the exit pupil will be 2.66mm on 18.8 power (50mm/2.66mm = 18.78) We'll be able to see clearly until 18.8power but the image will be darker at above this value.

Final Thoughts
The scope's image does not get darker because of the scope mechanics or glass quality. It gets darker because our eye and brain have to process more light information. Don't blame a scope for a dark crappy image on max magnification, its the human procces making the error.
Don't use high magnifications in darker conditions, our pupil is getting bigger so we need more light out of the optics to cover our pupil.

I hope this helps, have a good day.

Ahhhhh I see. (Sorry for the accidental pun!)

Hmmm I am not sure if I’ve ever semi-rigorously tested the same scene with two different brand scopes that have the same diameter front objective and same mag power. Gonna try that!