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Advantages of Large Objective Scopes

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cj_86

cj_86

Member
Jul 3, 2015
311
40
Illinois, United States
What are the advantages of having large objective scopes with 30 mm tubes on an air rifle? I'm looking at Hawke Sidewinder scopes and they offer some with 56 mm objectives! My brother in law has a 50 mm Bushnell Elite on his Remington 700 and that thing seems huge. Largest scope objective scope I own is a 44 mm and I'm quite happy with the performance of it. 

What are advantages of having a high magnification? For example, 32x

From what I know, which isn't much, 30mm scope tubes have more adjustment (clicks) for longer range shooting and maybe enables more light into the scope for brighter picture? So what would be advantage of having so much adjustment on an air rifle? Most of my shots are under 60 yards (rifle zeroed 30 yards) and If I do need to make poa/poi adjustments I just hold over using the mil dots on my reticle and not make adjustments to my elevation knob.

Anyways, whats everyones thoughts on this?


CJ
 
If you aren't going to be doing large turret adjustments then the benefit of bigger objective lens and tube is mostly the ability to gather light like you said. In my experience 30mm tube scopes have a brighter and clearer picture on average. For magnification the higher the mag the easier it is to dissect the bullseye of the target and get a finer aim point. However higher magnification is at the cost of field of view so as a hunter I prefer right around 10x for a good balance. The image quality at very high magnification can also be blurry especially on less than expensive scopes. I have a sidewinder 4-16 x 50 and like it a lot but it might as well be a fixed power because I never take it off 10x. 
 
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Light. Light. And more light. I have a 56mm primary objective (and 30mm tube) and as the sun sets (still very light) the shadows under the bushes start playing with your naked eyes. But you look through the scope and BOOM! It is like night vision and that possible squirrel is just another branch / leaf / etc. I've had experience with 80mm binoculars and the light they gather so I made a deliberate choice and am happy even with the weight increase because of all that glass.
 
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Matt,

I also have a 4-16 power scope and it is always on 10x when hunting. I took a shot at a starling at 50 yards and the pellet went right over its head because I forgot the mag setting was at 16x...so since then it never leaves 10x. I guess that is where a FFP scope comes in handy.

JR_Explorer,

Like I mentioned before my brother in law has a 50mm scope and you are absolutely right that it let's more light in and really brightens things up when light conditions aren't as ideal. I've been looking into getting a MTC Viper in 50mm and you guys aren't helping my wallet. Haha

Anyways thanks for the input.

CJ
 
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Smaller lenses are easier to manufacture without distortions, but poorer at light gathering. Scopes are lighter and more compact.
Larger lenses are harder to manufacture without distortions, but better at light gathering. Scopes are heavier and bulkier.

Small, very high quality objective lens are relitavely cheap.
Very large, very high quality objective lens are breathtakingly expensive.

Luckily, very high quality large objectives are not needed at 100 yds and in. You can get by with second tier glass just fine at short ranges.
 
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"Jr_Explorer"I love the reticle of the MTC Viper. But if you are budget minded look at the UTG (Leapers) 4-16X56. Etched glass reticle and goes for $200 vs $379. I have the UTG in 6-24X56 and love it. I think it's one of the best values in scopes out there.
Click to expand...

I have a UTG/Leapers 4-16x44 and really like it too. If I hunted more, I would probably have chosen the 56.
 
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"Jr_Explorer"Light. Light. And more light. I have a 56mm primary objective (and 30mm tube) and as the sun sets (still very light) the shadows under the bushes start playing with your naked eyes. But you look through the scope and BOOM! It is like night vision and that possible squirrel is just another branch / leaf / etc. I've had experience with 80mm binoculars and the light they gather so I made a deliberate choice and am happy even with the weight increase because of all that glass.
Click to expand...
You've got it backwards. The tube has absolutely zero impact on the light gathering. It is 100% adjustment range.
The things that impact image brightness and clarity is the objective size and coatings.
A scope will never. I mean NEVER EVER give you more light than what you see with your naked eye. It will ALWAYS be darker unless you have an artificial light amplification, such as NVD. The scope may appear brighter because you're filtering light noise away from your eye and focusing only on a specific spot (think of putting your hand up to block the sun to see someone walking towards you).

The key to a great scope is to use it where it works for you best. Shooting in darker areas? Get a bigger objective lens or pay for the better glass and coatings. I've held a Leapers Bugbuster (~$80) next to a Vortex Razer HD (~$1300) and the difference was jaw dropping. You get what you pay for in the optics world.
 
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"Valerike"
"Jr_Explorer"Light. Light. And more light. I have a 56mm primary objective (and 30mm tube) and as the sun sets (still very light) the shadows under the bushes start playing with your naked eyes. But you look through the scope and BOOM! It is like night vision and that possible squirrel is just another branch / leaf / etc. I've had experience with 80mm binoculars and the light they gather so I made a deliberate choice and am happy even with the weight increase because of all that glass.
Click to expand...
A scope will never. I mean NEVER EVER give you more light than what you see with your naked eye. It will ALWAYS be darker unless you have an artificial light amplification, such as NVD. The scope may appear brighter because you're filtering light noise away from your eye and focusing only on a specific spot (think of putting your hand up to block the sun to see someone walking towards you).
Click to expand...
You sir have never looked through a pair of binoculars with 80mm or 100mm primary objective lens at dusk / night... Or a 12" telescope for that matter. Why do you think the Navy and Coast Guard use those huge, heavy binoculars?
 
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Interesting information Valerike. I've always thought scopes gathered light and made the image in the scope brighter then normal. I guess I thought this because of all the marketing that scope makers put out there about light gathering.

When a scope advertises specs... what is, for example, 95% light transmission mean? I tried to google it ,but wasn't able to find the answer I was looking for. 
 
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"JR_Explorer,Like I mentioned before my brother in law has a 50mm scope and you are absolutely right that it let's more light in and really brightens things up when light conditions aren't as ideal. I've been looking into getting a MTC Viper in 50mm and you guys aren't helping my wallet. HahaAnyways thanks for the input."
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CJ
I have a 4-16x44 Mamba Lite and absolutely love it. It's only got a 1" tube and very light in weight. You should like the Viper. I have a MTC 5-20X50 Genesis and can't stand the reticle on it. I put it on my Shinsung Dragon Slayer since I don't shoot it very much.My little Mamba and big ol ' 8-32X56 Hawke are my two favorite scopes. And I've got a cheap 6-24X44 BSA on my FX that's excellent for what it is. It's my third favorite scope.I've been contemplating the SWFA SS 3-15X42 http://swfa.com/SWFA-SS-3-15x42-Tactical-Rifle-Scope-P62238.aspx
 
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"30cal"Valerike is correct. There is no possible way a conventional optic can be brighter than the existing light! It only appears brighter for the same reason that things look bigger though it. It magnifies the image which allows you to see more detail.
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Large lenses do indeed gather and amplify light. Lenses focus light on a smaller area, thus amplifying light. Theoretically, any lens larger than your retina can brighten the view.

A couple of examples are a plain magnifying glass and an astronomical telescope. Take a magnifying glass and focus it on a sunlit object. The sunlit object is bright, but the focused beam of the magnifier is up to several times brighter. Without large magnifying mirrors in astronomical telescopes, very dim stars would never have been detected.

I have an indoor range with several lights. When all lights are on, both my 16X scopes are plenty bright. When a certain light is not turned on, my 30mm tube 44mm scope is fine, but my 1" tube 40mm scope is too dim.
 
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"Jr_Explorer"
"Valerike"
"Jr_Explorer"Light. Light. And more light. I have a 56mm primary objective (and 30mm tube) and as the sun sets (still very light) the shadows under the bushes start playing with your naked eyes. But you look through the scope and BOOM! It is like night vision and that possible squirrel is just another branch / leaf / etc. I've had experience with 80mm binoculars and the light they gather so I made a deliberate choice and am happy even with the weight increase because of all that glass.
Click to expand...
A scope will never. I mean NEVER EVER give you more light than what you see with your naked eye. It will ALWAYS be darker unless you have an artificial light amplification, such as NVD. The scope may appear brighter because you're filtering light noise away from your eye and focusing only on a specific spot (think of putting your hand up to block the sun to see someone walking towards you).
Click to expand...
You sir have never looked through a pair of binoculars with 80mm or 100mm primary objective lens at dusk / night... Or a 12" telescope for that matter. Why do you think the Navy and Coast Guard use those huge, heavy binoculars?
Click to expand...
Larger objectives increase the amount of light that can be gathered from where you are looking, but it is never "brighter" than the light being sent to your eye naturally. The glass and lenses will reduce the light. Hence why a statement of "95% light transmission" means that 95% of the light that hits the outer edge of the objective lens will reach your eye. The reason for larger objective lenses is not because they amplify the light, but that they allow more light to reach your eyeball.

When you are standing outside and you grab a toilet paper roll, you can put it to your face and you can see better when looking towards the sun since you're filtering away light noise or glare. Larger objectives are absolutely more effective during low light conditions. Either way, you're running into semantics when discussing if it actually does increase the light. It does appear brighter than smaller objectives, but so does the quality of glass and coatings. A $800 pair of 20mm Swarovski's will be brighter than 40mm Barska's
 
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I have a background in telescope optics and can help with some clarification.

The pupil of the eye can dilate to 5-7mm (younger = bigger), which determines the amount of light entering the eye. Light entry is a function of the area of this circle. When you look through a telescope, the objective ("field lens") gathers light far in excess of the naked eye because the area of the objective is many times greater than the pupil.

In essence the objective collects light and concentrates it into the eye's entrance pupil.

The light coming out of the eyepiece of a telescope is called the exit pupil. The diameter of the exit pupil is the objective diameter / magnification.

For example 7 X 50 binoculars (two telescopes) have objectives that are 50mm diameter, and magnification is 7X. So the exit pupil is about 7mm.

Now an important point: A 7mm exit pupil is stopped down to a smaller diameter by the eye's entrance pupil if the eye's entrance pupil is anything less than 7mm. That is, when using 7X50 binoculars in bright daylight when your pupils are constricted, much of the diameter of the objective is not being used. Think of putting washers over each lens to stop them down. If, on the other hand, you are dark-adapted (and young) and using 7X50 binoculars in the dead of night, you can use all 7mm of the exit pupil and therefore all the light-gathering power of the full 50mm objectives.

All this of course is true of riflescopes. Divide the objective diameter by the power used to get the exit pupil (varies in variable mag scopes). If you're using a combination that results in >5mm exit pupil, the extra light gathering is wasted in daylight. This won't hurt anything, but the utility of large diameter objectives is low-light conditions.
 
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