I’m looking at two scopes. One is a 2-7x33 and the other is a 3-9x40. The field of view in both scopes at 100 yards is in the specs. I know little to nothing about scopes. Will there be a visible difference in the amount of light one sees thru the scope between a 33mm and a 40mm objective?
The manufacture and line within the manufactures scopes is the same. This will not go on an AR, rather a bolt gun, and will be used from 25 yards out to 300 yards.
The simple answer is… A larger objective lens will gather more light than a smaller one. The problem is everything isn’t that simple! A well designed 33mm may out perform a poorly built 50. Glass quality, lens coatings and design all contribute to the scopes performance.
I understand that, but would one even notice the difference between 33mm and 40mm given same manufacture, same line of scopes?
Objective lens size determines your exit pupil. To see the exit pupil of any optic, hold a white piece of paper behind the eyepiece at the proper eye relief distance and you’ll see a little circle of light. If your eye is outside that circle you can’t see through the scope. Thus a smaller exit pupil means a smaller eyebox and makes it more difficult to use.
Exit pupil diameter = objective lens clear aperture / magnification. The 2-7 should have a 4.7mm exit pupil and the 3-9 should have a 4.4mm exit pupil. Doubtful you’ll be able to tell the difference.
As far as the brightness of the image or light transmission, that is largely dependent on the number of lens surfaces (opportunities for light to reflect) inside the scope. Quality of coatings and the overal prescription can help or hurt but if both scopes are from the same manufacturer and the same model then likely they are equivalent. With a larger objective lens sometimes they’ll stick an extra piece of glass in there which means two more surfaces that will hurt light transmission but not at a level your eye can likely discern.
You may or may not notice a difference. Just because a manufacturer makes a XXX line with a 33 and 40 in it really means nothing because they are both built with different recipes. If the manufacturer is reputable you should see a difference in low light performance but we are probably only talking about an extra 5 minutes before dawn or after dusk. At high noon in an open field I doubt you could see a difference between a 33 and a 40 if both were the same quality. Hochitz sounds like the resident expert here. He can probably explain it better than me.
You would probably notice the difference early in the morning or later in the evening, justification enough to go with the larger objective lens. I had a Leupold 2.5 X 8 Vari X 3 years ago and my Leupold 3 X 9 AO ran rings around it with the larger objective bell.
When a manufacturer offers a line of scopes at different magnification ranges, all with the same zoom ratio of 3:1, 4:1 or 6:1, that usually indicates the erector systems use the same internals. There’s no reason to use a different eyepiece so in practice the scope is identical from the front focal plane back. If you (the mfr) already have a 1-6 you can simply put a bigger objective on it and get a 2-12, 3-18, 4-24 etc. Alternatively if your competitor is offering a 3-18 you can bump your objective slightly and get a 3.5-21 which sounds just a little bit better to the customer. The higher mag objective by definition has a longer focal length making the scope longer and bigger in diameter to keep your exit pupil large enough to use. The only other difference is the adjustment screw pitch which has to get coarser to compensate for the larger image. When the magnification gets really high the image inside the scope gets so large that the 30mm tube you started with doesn’t allow enough travel requring a change to a 34mm tube, all with the same internals as the lower mag scope.
In short, the glass is most likely identical in the rear 2/3rd of the optic with a different objective lens plus one or two elements behind it. If the objective of one is designed poorly then it could look worse than the other but generally it’s the same person designing all of them to the same standard of quality and cost for that line.
I’m thinking I may only notice a difference if I have the two scopes side by side in the area I do most of my shooting, but I just had to ask.
The two scopes are the Redfield Revolution 2-7x33 and the Redfield Revolution 3-9x40.
The gun the scope will go on will be the CZ 527 in 7.62x39. It is a bolt action carbine that comes with iron sights that I intend to use. The scope will be installed with the ["]Warne Quick Release Rings](http://www.amazon.com/Warne-Scope-Mounts-Detach-1-Inch/dp/B0029M43Y6/ref=sr_1_2/189-5456016-9964232?ie=UTF8&qid=1418757180&sr=8-2&keywords=warne+quick+detach+rings[/url).
The 2-7x33 is probably the scope I will go with because of the bell size. The 40mm objective size will mean removing the rear sight, but I want to be able to use the gun with iron sights and to be able to remove the scope at will. All the videos I’ve seen on the Warne Rings allow the scope to be removed and reinstalled often without losing zero.
The answer is the objective diameter does not necessarily correlate with increased brightness
This is a seemingly simple question with a pretty difficult answer
Say we just scaled up the diameter of all lenses in a riflescope, including the objective, but kept everything else constant. We now have greater flux but at the exit pupil this doesn’t necessarily mean the image looks brighter because the exit pupil diameter has just increased as well (greater power but not greater power per unit area aka irradiance because the area of the exit pupil has increased).
On the other hand, if you change the design you can get increased throughput and you can actually make the image appear brighter.
Ok, I’ve decided that the Redfield Revolution 2-7x33is the scope I will go with. Now, I just have to wait for the gun to come back into stock somewhere. Thanks for all the answers.
Scopes done gather light, they transmit. The objective size, along with magnification, leads to exit pupil. Generally, you want as large an exit pupil as you can get, up until the point of the anatomical limits the human eye can perceive.
What matters more about a scope being “bright” is the lens quality and coating.
More important than the quality of the image, is the functionality and durability of a scope. Rarely does one miss a shot because of image quality. I usually consider good knobs and a durable scope that holds zero through abuse better than pretty images. I broke a couple of beautiful Conquests and Leupolds that rendered the gun non-functional. That will ruin your shoot/hunt faster than anything.
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just so that you know, you cannot use the Warne rings that are made for Weaver bases. you have to use the ones made for 16mm CZ bases. the Amazon link is to Weaver style ones.
Also, because of the weird bolt handle on the CZ527, you have to have high enough rings to clear the power ring and eye bell of the scope. I am assuming that is why you picked the high Warne ones, but thought that I would mention it.
My 527 came with CZ rings in the box, but not all do apparently.
I love the CZ527. I have been shooting it for 3-4 years now and its light and handy for walking around.
I believe the 527 Americans come with them, but Varmints do not.
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How can you tell the link to the Warne Rings will not work on a CZ? I can’t find any info that says they can’t, but I know nothing about base rings. I hear the term “Weaver Rings” tossed about a lot, but I really know nothing yet. This is till quite confusing to me.
I picked the high rings so that the bell of the scope will clear the rear sight.
I do believe all CZ 527’s come with scope rings, but I want quick release rings.
It is my understanding that CZ makes a redesigned bolt handle that will work with scopes and is available on their web site. I’ve also heard that the redesigned bolt hands come with new 527’s now, but that is unconfirmed.
CZ has an integral dove tail that won’t work with weaver.
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Does Warne make a quick release ring that does work with the CZ mounts? If so, where does one find them?
Are you set on warne for some reason? If so you could maybe find a weaver rail that will attach to the dovetail. I’ve not personally seen any Warne to fit CZ. Just CZ brand, Leupold, Millett, etc.
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I’m new at this, and Warne is the only quick release rings I’m aware of so far. Warne seems to make a nice product, but if there is something comparable out there, I’d certainly like to know. If I can’t find quick release rings for the 527, I may have to pass on this rifle.
Can the CZ ring mounts be removed and replaced with Weaver style mounts?
You can find a few adapters to adapt the CZs. You can’t take off he CZ dovetail, as its integral to the receiver.
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http://kinneysshootingsupply.com/16mmpicatinny-piece-adapter-19007-p-1232.html
Here’s what the first Google hit was for me. Besides Warne, I know Leupold makes QD rings, and ARMS, LaRue, etc.
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