Home Forums Hunting & Shooting Hunting Optics When does 50 mm + objective become useful?

As I get older, I find I need more magnification for certain shots. Low/bad light and shadows are more of a problem. Being able to see the target is just harder. My lower power scopes are just not as easy to use now as in the past. In good light, the scope is cranked down but more often I'm having to turn them up. As I'm moving towards higher magnification scopes I wonder at what point a larger objective starts to really pull away from the usual 40mm and under what conditions it makes a difference. I don't presently own anything with a larger objective than 40mm. I've never noticed any difference between a 40mm and 50mm scope in the 3x9 magnification range. Does a difference start to show up at 12x? 15x?, higher? For my purposes, lets keep the discussion confined to scopes of good brands at less than $1000.00.

I have an assortment of 50 and 56mm scopes. They are great but the game changer now is lens coatings and glass quality. The Swaro Z5 ($1,200 ish) 44mms I have used the past couple of years are fantastic. They very well could be "better" in low light than my older 50 and 56mm Leupolds, Swaros, and Zeiss. My point is, look at the top brands in your price range and you might find a 40-44mm has the quality you want without having to have a larger objective.

Technically without any dollar value attached, divied 50 by 3 for a useable eye diamater at full light and you get 15 x. If you go above 15 x then then to maitain the 3 mm eye number you need a larger objective. This doesn't account for glass quality or coatings etc.

I don't think you are going to see much difference between 40mm and 50mm. Pupils only dilate to about 7mm, diminishing when you get older. If you are 50+ i would think a 5mm dilation would be common. With that said a 50mm at 10x provides you with a 5mm exit pupil compared to a 4.44mm for a 40mm at 9x. As you go up in magnification you will be able to see more detail but the image will be dimmer

Exactly what happened to me when cataracts started. In fact, I noticed it before my Dr. could find the problem. A Year later He said that cataracts had started but were not bad enough to have surgery. I found that going to a 50mm from a 40 mm helped in low light situations, more so in the afternoon with failing light compared to morning with gaining light, but some both times. After surgery, I could not tell as much difference but after 10 years I am noticing problems again. Not bad but some. miles

Talking only of equal glass I have discovered a 50mm seems to have a little better quality image than a 40mm. For sure the 50mm will last longer in low light when both are on the same magnification setting. Absolutely turning up the magnification allows you to go later into the dark. I proved it on my porch. Mule Deer proved it with his low light test and Jim in Idaho proved it in Africa on a hunt.

Over 12x or 30 minutes after sunset with high $$$$ glass under 12x

A larger diameter objective lets you turn the magnification up higher and not lose the brightness of the image. A 56mm objective at 10 power gives you an exit pupil of 5.6mm which is about as much as the eye can use. A 40mm objective at 10 power gives you a 4mm exit pupil which is going to mean the image brightness is limited by the scope and not your eye, you'll have to turn the power down to get the brightness back and in doing so you lose some of the advantage the extra magnification gives you at last light. I've found the ability to use the extra magnification in low light is crucial to making a good shot. A shot that could easily be made at 4X in daylight becomes difficult as the light fades, being able to turn up the magnification and keep the image brightness is important when hunting last light. My main deer rifle has a meopta 3-12x56 with a #4 reticle, it's a great low light scope. I hunt mostly food plots in Mississippi where the good deer show themselves at the last minute if at all. I've made shots with it that wouldn't be possible with the standard 3-9x40 that lots recommend. I hunt from stands and don't care about the weight or the handling, I'm not hiking with it. It's a specialized tool that does the job it's intended to do wonderfully. Many on this board like to make fun of the "hubbles" but it mostly shows that they haven't used a really good low light scope under the situation it was built for, if they had they'd understand why they exist.

If you're really interested in a scope that'll take care of your low/bad light situations then take a look at the Schmidt & Bender 2.5-10x56 listed in the thread I linked. It's a fantastic bargain at that price, that scope is the cat's azz for what you're describing:

https://www.24hourcampfire.com/ubbt...le-your-choice-only-1295-00#Post12324054

A different, but related matter is whether or not you can see the reticle. Just came in from testing my 6x42 SS at official sunset. In my yard, in the shadows, I couldn't make out the reticle center on darkish objects. The posts don't come close enough to the center to make aiming certain, except very close up. Our legal shooting time runs a half-hour later than that. This was a worst-case test, as it's been very gray all day.

Don't know how much field time this rifle will see in the coming season, but unless I mount another scope, it won't be in the evening, exept possibly if there's snow on the ground.

Super chickens are daytime dialing scopes... good for that but for the price, you are sacrificing coatings on the glass... they have always been middle of the road in that department, for the pirice point not bad, but as all thigns it is a compromise and it depends on your field situation/ needs.

Crow Hunter-

You hit the nail on the head about requiring more magnification in low light than in strong daylight. When people ask about low-light performance, I see many replies recommending "a good 2x or 3x." While that may be OK for very short distances, it would not have worked for any of the moonlight shots I have made in the past couple of years. Rarely do I use anything as low as 8x, and most times, it's 10x or more.

Thanks for the replys. I'm getting that about 10x plus the bigger objective's brightness starts to be a noticeable improvement. Related question: what magnification range works best?

Is there any usefulness in having a top mag range above 12x? 15x higher?i mean for picking up a target in bad lighting

One thing I've noticed is that the two 50mm scopes I've had seem to have a more easy to get behind view at all powers than same model in 40mm. Not sure it looked brighter but eye positioning was easier.

I missed the Jim in Idaho Africa Hunt what scope did he use?

He used a 1-6X. He couldn't see the animals until he turned it up to 6X.

For very low light, say at or past 30 minutes after sunset, an exit pupil (EP) of 5mm works pretty well for me, generally speaking. The assumption here is that your own eye's pupil will open up that far. So a good 50mm riflescope scope at 10x or 10x56 binocular fit the bill for my low light use. Or for that matter a 42mm riflescope at 8x will get the job done--it will show more detail at 8x than 6x--somewhat dimmer, granted...). An excellent 42mm will do all you need it to in most low light hunting, but a larger objective in the same quality glass will do it a little better and you will find advantages with a 50mm or a 56mm--like Crow & Bobby said.

Power is an asset to the "mature" hunter. Greater power requires more objective size to keep a given EP, and at some point there is a limit to what you want on your rifle or willing to carry. The less light you have also puts a practical cap on the range. For me, some field of view around the critter is helpful, and 10x at 200 yards works pretty well in that regard.

If you look through enough scopes 30 minutes past sunset or under moonlight, you see there are differences--some are subtle and some aren't. Some are better earlier in twilight and some are better later. Sometimes the eyebox gets fussy when the light wanes. You have to compare them side by side or take copious notes under controlled lighting. A lab would help... For me, I compare side by side for the best performance in view--what the glass will show me in small differences over its brethren--the one picked may not necessarily be the brightest. And the rub is, a lot of it may be subjective to the viewer.

Overall the differences are small and when guys reports that a certain glass adds 15 minutes of time to their hunt, they were either selling a product or did the comparison at different times under different light conditions.

Swaro, S&B and Zeiss have been making scopes for shooting porkers in the dark for a long time...and to make sure all your cash is spent, personally I put far more emphasis on the quality and low light view of the binocular over the riflescope for results.

fwiw...

You might want to take a look at the first plane reticle 30mm European scopes because the crosshair covers the same amount on the target as you increase the power on a variable and at the upper power settings those reticles really stand out. I've got nothing larger than a 42mm objective because I like lower mounted scopes for a better cheek weld. Those Europeans get to hunt way later into the evening than we do, so a higher end Euro scope with the first plane reticle and better lens coatings would serve you well in low light hunting here.

Assuming equal quality scopes 50mm objectives offers better usable light transmission over a 40mm scope only between 8X and 10X magnification. Anything over 10X and there is no difference. Anything below 8X and the human eye can't use the extra light.

Assuming equal quality a scope with a 50mm objective will cost $100-$200 more than the same quality 40mm scope. At the same price point a scope with a 50mm objective is a lower quality scope. I've found that moving up and paying $100-$200 more for a better quality scope with a 40mm objective gives better results than spending the same money on a scope with a 50mm objective

To be clear: I could see what I was aiming at, but not what I was aiming with. A similar reticle with a dimly lit aiming point would have made all the difference as would posts that came closer to the center. This is where the long-range dialers fall short as hunting scopes, at least in the woods. I realize that many use them with good success in open country where it's easier to see, even early and late, and where there may be time to bracket the target, but up close in the gloom on a moving target like a traveling or feeding deer, those reticles put you at a considerable disadvantage.

At my next opportunity, I'll do the same test with the TPlex in my Tract, also a 42mm, set at 6x. Since the posts come much closer to the center, I expect it to do better. Also in the pipe is a humble Weaver K6 with a simple duplex. That one, if it passes the test, can go in the spare low rings I have on my Ruger for the season.

As a younger person I thought those big 50mm scopes were ugly and unnecessary. These days I'm using a Zeiss HD5 in 3-15x50 as my go to hunting scope and can't imagine going back to a 40mm given a choice. I still shoot targets and varmints with down to 32mm scopes but for hunting bigger seems better now.

I like the 50mm VXIII’s by Leupold.

Perhaps this is most people's experience. I compared Swarvoski z5 5-25X52, Leupold VX-6 4-24X52, Bushnell 6500 4 1/2-30X50 side by side on deer antlers at 131 yards. They all went down at the same minute. Then on another day I compared the 6500 with the new Leupold VX-5 3-15X56. The VX-5 lasted six minutes longer than the 6500.

On another evening I compared a Swarovski z8i 2.3-18X56, Swarovski z6 5-30X50 and a Bushnell 6500 4 1/2-30X50 side by side. The z6 went down at 7:13PM, the 6500 went down at 7:24PM and the z8i lasted until 7:44PM. That means the z6 went down eleven minutes before the 6500 and the z8i lasted an additional twenty minutes. The owner of the two Swarovskis told me, "I knew that z6 wasn't very good."

The z6 and the first three z5's I bought proves beyond a doubt one doesn't get what one pays for.

A large objective diameter has two useful effects:

a) it increases the size of the exit pupil of the riflescpe
b) it increases the theoretical resolution of the riflescope

The effect (a) in turn does two things:

(a1) It gives you a larger more comfortable "eye box" behind the scope so precise eye position becomes less critical.
(a2) It provides a brighter image at dawn or dusk if your eye pupils enlarge enough to be able to use the wider exit beam.

To me, the effect (a1) is the most desirable for hunting. It makes it very easy to look through the riflescope and acquire the target. Effects (a2) and (b) are good to have too. If you have a high-power scope (say more than 10X), then you do want to have a large 50 or 56 mm objective so that the image resolution is sufficient. With power more than 20X, the air turbulence effects become so noticeable that adding more power or more objective diameter doesn't add much to image quality. Also, hand shake becomes very distracting.

In the good old days, the diameter of the exit pupil of a riflescope was it objective diameter divided by its magnification. With the advent of large zoom-ratio scopes such as Swarovski Z6 and Z8, this is no longer true. At low power, the internal apertures limit the light beam diameter passing through the scope so, for example the Swaovski Z8i 2-16X50, has an effective aperture of only16.3mm at 2X so it is actually a 2X16 scope at its low power!! As a result, it only provides an 8mm exit pupil at 2X. For comparison, a 2.5-10X50 Zeiss Varipoint riflescope provides a 15mm exit pupil at its lowest power, making it it a much "faster" scope for shooting at running game at low power.

While the extra zoom ratio is loudly advertised, the limitation of the internal apertures is not.

-Omid

Omid,

In my last post you will notice the z8i lasted twenty minutes longer than three good scopes; and 31 minutes longer than a Swarovski z6. What do you think allowed this. By the way, both the owner and I agreed when the scopes went down.

I have been able to shoot deer using a Zeiss Victory HT 2.5-10x50 that I would not have been able to shoot using my VX6 2-12x42. The 50mm is worth it to me. In fact, as I am getting older I am considering going to a 3-12x56 for hunting out of blinds or when still hunting.

IMHO the two go hand in hand. You need to be able to safely and properly pick out the "right" target when looking through the rifle's scope. This is important in very low light when transitioning from binoculars to scope when there are more than one animals in close proximity to each other.

I’m curious. Do you think that having an illuminated Firedot reticle would negate the need for a 50mm objective over a 40mm objective? Wouldn’t almost any quality optics of say a 36-40mm be able to resolve the animal enough in low light to make the shot unless we are talking a fairly long range shot?

Hi Rigman,

My comments above don't contradict your observation. The Z8i's exit pupil is sufficiently large for low-light observations at low powers (8mm is still larger than max dilation of human eye pupil) and at high power it will act like any other scope and its brightness will depend on the "actual" objective size. The Z8 scope you tested had a 56mm objective lens compared to 50mm in others. A 56mm objective collects 25% more light than a 50mm objective (lens area is 25% larger) so it will look brighter at medium/high power. What power did you use for your observation? Did you compare all three scopes at same power, say 10X?

-Omid

Ringman, did the owner of that Z6 talk to Swaro customer service about it?

I don't remember what they advertised as light transmission data for that scope, but the current Z6i says 90% and that is comparable to most of their stuff. Interesting that the Z8i is 3% higher.

tomk,

I don't know. He's owned that z6 for several months so I doubt it.




Omid,

As much as is possible all the optics I play with are set on the same magnification setting. I called Swarovski, Leupold, and Bushnell about the accuracy of their magnification ring settings. All were adamant the numbers are accurate.

The owner of the two Swarovskis was a little late arriving. Since the z6 was the poorest performer we used it on the lowest setting on which we could clearly make out the 13” wide deer antlers 131 yards away. That was 15X. The z6 and the 6500 both have 50mm objectives. And yet the z6 (costing about 2 ½ times more) got beat by eleven minutes.

In my comparing I discovered exit pupil when looking for good low light performance is a joke. Along those same lines I compared my Minox 13X56 (two 56 mm objectives) with my Bushnell 6500 4 ½-30X50 (one 50mm objective). I set the 6500 on 13X. It lasted two minutes longer than the Minox. I traded the 13X56 for a Minox 15X58 (two 58mm objectives). It was so much better I thought it might be as good as the z8i. Not so; although it did beat the 6500 set on 15X by nine minutes. But the z8i (one 56mm objective) lasted eleven minutes longer than the Minox 15X.

No,

I'd trade my Minox i 20 x 56 for a good 40 mm. Don't get me wrong, it performs well. But it's too damned big.

How does tube diameter affect the objective. I like the 30mm tube with a 40mm objective on my Leupold 4.5x14.

Gentlemen:

For the record, as I wasn't clear about this, the comparisons I was referring to were at the same aperture, i.e. the same exit pupil. I get good results in low light down to 5mm area.

IMHO, no, and yes. As mentioned earlier in this thread, using my SWFA 6x42, I could see my "targets" (various darkish objects in the shadows of my yard) but not the reticle. I think that the two problems are separate issues. If anything, a lighted aiming point will make it harder to see the target under very dim light because it will cause your pupil to close a bit. Possibly the larger objective would help overcome that.

The deer I shot moments before legal shooting time ended last year was quite visible at 20 yards or so through the Mark AR Mod 1 1.5-4x20 on my .308 and the green dot, set very low, stood out very well. After the shot, she ran off with the others and stopped about 80 or 90 yards away. At that point, I could see the others well enough that I thought briefly about dropping another one. With my naked eye, the only way I could tell when she flopped over seconds later was by the flash of her white parts. If a 20mm scope let me see that well, I feel pretty certain a 40 would have been even better.

One of the things I often do while waiting for legal shooting time in the morning is checking to make sure I can see my sights. I've always been able to make out my ordinary duplexes in 2-7x33, 4xwhatevers, and 3-9x40s before it was legal to shoot. Until last year, I usually left the woods a bit before the end of legal shooting time for safety's sake, but last year, hunting on private land, I stayed late several times. Again, checking through my scope, I could see well enough to shoot until the final gun, at least in the open field I was watching. A little more light wouldn't have hurt though. If a larger objective helps YOU, go for it.

when does a 50mm obj become needed for hunting? unless its some sort of specialty hunting I am going to say hardly ever. I have been using a 2.5-10x32 NXS compact on my calling rifle the last couple years. seeing a coyote in sage brush is hard even with excellent light, seeing one in bad light well that is really tuff. With the distances you should be shooting at or should I say NOT shooting at. 5 or 6x is all you need your scope at, even with the small 32mm objective its still plenty bright at that power. 5 or 6x with my little 32mm obj I can make a shot on a coyote out to at least 250 yards until its not legal light to shoot anymore.

The one that surprised me the most was my 1.5-5x20 Leupold with the Heavy Duplex. I put it against my 30 mm tube Zeiss & Swarovski 42 mm objective Euro scopes and that Leupold Heavy Duplex stood out well past legal light. The standard Duplex reticle in the Leupold 2.5-8x36 disappears in low light much faster.

And THAT my friends is key. Our own JJ Hack pointed this out to me years ago and a HD really helps to close the gap of superior glass. For example, my Z6's incredible glass, but thin crosshairs, when compared to one of my Leupolds VX3s both set to the same magnification and similar objective lenses (42mm V 40), the heavier X hairs on the Leupold allowed that scope to hang in there and in some cases surpass the Z6, all due to the heavier reticle. The down side to this is of course target fidelity, but it is a tradeoff.

I can't afford alpha optics so getting them with their excellent glass and coatings won't happen for me.

I do have a Bushnell Elite 4200 in 2.5-10x50 that I use on my 270 WSM. I use this where the shots are often 200 yds plus and often shots are closer to dusk than any other time. It has served me very well.

For my eyes, I find that this scope does stay slightly brighter than other scopes of the same price point with smaller objective diameters.

Dan

I wouldn't sweat not buying alphas, as we are talking low light hunting here, not shooting at 1000yds. A great low light reticle in a good scope ought to do. If you are having trouble with the seeing the target as the OP stated, you can pick up performance with some more magnification and an applicable objective to brighten things up without breaking the bank.

George has hit the nail on the head,for low light hunting,one is often limited more by the thin design of many reticles than by the optical brightness of the scope.

But it is possible to have your cake and eat it too. You can use a scope with really good optics,a large diameter objective lens,and a really bold reticle. European variables with first focal plane reticles naturally look bigger and bolder to the eye as you increase magnifciation so they are perfectly suited to the really low light game.

The same European scope with a thin second focal plane reticle will enable you to see the critter but the reticle is no longer visible. That is why many of the Euro scopes with second focal plane reticles are offered in illuminated versions.

My favorite scopes for low light hunting are Euro Variables with 50 or 56 millimeter objectives coupled with bold first focal plane reticles or good illuminated reticles. Such scopes allow me to kill hogs at night under star light without difficulty on most any clear night with any moon light at all. They actually work better than the Generation One night vision systems that I have tried,if that doesn't tell you something I don't know what will.

After quite a few years and quite a few scopes, my 1.5-5 x 20 continues to impress. It's the last scope I'd get rid of.

similar, I just tried one of the 1-4's this saturday at sunset plus 20 min the image was mush, could not make out an anthill at 100 yards on 4X, the reticle lighting is so so but works, still not a usable device in low light.

In talking with Leupold Techs, never.

They sell 50 mm scopes because of demand and a perceived gain.

As to 50mm being needed: All I can say is those who have been down the road and have the experience fully know the answer, and THAT is why the 50 and 56mms sell. Sure, some buy "just because." But if your shot opportunities are few and far between -- and if, like me, you are not mobile and can't stalk closer -- that 36mm objective on a 2.5-8x VX-3 will prove utterly useless on a 175 yard hog in weak moonlight. Some will talk about exit pupil, but you HAVE to have magnification under those circumstances (not to mention a visible aiming point). Trust me. Been there. Done that. I've tried all sorts of scopes that would be up to the task for this sort of usage, and not a single 40mm objective cracks the top 25 in my experience.

There are a precious few scopes which boast both the resolution and contrast to even allow 6x to be a viable option at 100+ yards (in moonlight/very low daylight). 8x usually works fine, but if you can get 10x or more, then all the better. You can crank a 40mm objective all the way down to 3 or 4x and have an impressively-bright image, but I assure you making a humane shot at extended ranges will be out of the realm of possibility. You simply won't be able to discern enough detail. Hunting under moonlight or very low light is a completely different ballgame than shots taken in decent daylight.

Bobby what about a green or red light for the hogs? I am getting close to buying a 28mm objective scope but I plan to use it with a green Wicked light.

Red almost never spooks them; green does on occasion, but they don't seem to be in a hurry to vacate the area and still allow time for a shot. For me, dark hogs are harder to see in a red beam than a green, but everyone's vision is different. If you slowly lower the light onto them rather than blasting it on directly at them, they are less likely to spook -- even when a pure white light is being used.

Have found this advice to be spot on...I like the green light, mainly because its what Ive used most, but did kill a hog the other night with white light. Kudos on the slowly lowering the green light on them.

As for 50 mm scopes....No.More marketing than anything else thats practical.

Bobby I have a red/green VLR-1 I bought from Selph Arms fellow named Brad I think, its a good light and has two LED's red and green. The wicked light I bought is heavier but has more beam power in my opinion but I just use the smaller one more often due to weight. I agree at low power the image in a 50mm scope seems easier to find, but I have not hunted with a new 50mm objective with newer coatings after dark, my experience there is limited.

At sunset plus 30 the little 1-4 SWFA craps out tested this saturday, I don't think the coatings are that good on the 1-4's and someone else has alluded to the fact they are daylight dialing scopes.,,, makes me wonder about their HD line if they are any better regards lower light??

Yes Leupold does suck immeasurably with their mechanics however the older VX6 1-6 24 mm objective and heavier reticle is awful close at 4X to a Zeiss victory with a number 60 in it 1.5-6 x 42 random testing by peering off my deck near dark and hunting with both until sunset plus 30. It almost makes it worthwhile in the $1000 Leupold to put up with the adjustment BS if only on a hunting rifle you use locally.

When its after 30 minutes from sunset, I have a mounted and hand held light! so I am probably dumbassidly considering a Trijicon FFP 1-8 x 28 for a new night hunting rifle I am putting together, this plus a red/green light and I for the life of me cannot understand why this would be a handicap over a Zeiss, or SB, or Swarovski with a 50 mm objective considering I am using the light.

With auxiliary lighting as you plan to use, virtually any scope with a decently-heavy reticle will suffice. While I do not use lights very often anymore, one of my favorite scopes for this is the B&L 3000 3-9x40 with duplex reticle or the later Bushnell 3200. In fact, I'm probably going to list my B&L soon since I just don't get a chance to use it anymore.