with the option to choose between 1 inch or 30mm why would i want a smaller tube? given the same zoom with a larger tube you would get better light transfer and fov?
if that is so why is there so many 1 inch model scopes? is it just to be compliant to the current norm?
thanks greg

The tube diameter has zilch to do with field of view (largely determined by magnification and construction of ocular).

It is somewhat doubtful whether the tube diameter has much to with light transmission either. Admittedly, the scope manufacturers like to list this feature as a great advantage in terms of light transmission - but I'm somewhat doubtful if this is much more than a marketing ploy. What really matters in terms of light transmission are the number of glass-air surfaces (i.e. the number of lenses) the scope contains, and the coatings used on these surfaces.

What 30 mm tubes do give you is a higer ratio between the lowest and the highest magnification you can get from the variable magnification. 1" tubes will typically give you a ratio of 3 (3-9 or 4-12 etc.), whereas a 30 mm tube will give a ratio of 4 (2.5-10, 3-12 etc.) Some 1" scopes are labelled as having a magification ratio of 4, but I have the feeling this is a question of creative marketing. Most US and Asian manufactured scopes don't list exact magnifications - e.g. a 2.5-8 might in reality be a 2.6-7.8. If you take that game far enough, I guess you approach a 4x zoom with a 1" tube...

In my scope buying career, I don't believe I have ever bought a scope just to get a 30 mm center tube. But I have bought 30 mm scopes to get the larger zoom factor. Also, because most European scopes are made with 30 mm tubes (for whatever reason?), and because European scopes are what to get if you are interested in low light shooting (both in terms of reticles and coatings), I have ended up with 30 mm scopes when I wanted a scope to cover this application.

One advantage of 1" scopes is lower weight. Often, 1" scopes are also cheaper - possibly because smaller lenses are fitted??

- mike

I'm largely in agreement with Mike. Despite the intuitive appearance that a larger pipe would "let more light through", it is the size of the lens on the objective that determines how much light there is to work with, and transmission from the objective to the ocular is not enhanced in any way by having a pipe that is any larger than necessary.

However, I slightly differ with Mike in that I doubt that a wider zoom range is a realistic benefit of tube size. Zoom is limited by other factors and any diameter scope could zoom all the way down to 1X (or less, I suppose). It is more limited by the LENGTH of the scope than by the diameter of the tube. Keeping the eye relief and eye placement window within a desirable range is also a problem as you increase the variability of magnification, which is largely the reason most scopes limit their zoom to about 3:1. Leupolds are actually more like 2.65:1.

At any rate, the only actual benefit to a larger tube is a greater range of reticle adjustment, as there is simply more room inside the tube to move the reticle up and down and side to side. Curiously, Leupold's line of 30mm tube scopes does NOT show, according to their specs, an increased range of reticle adjustment.

Otherwise, the 30mm is simply heavier and bulkier, so if you have a gun that needs holding down, a 30mm scope might be a good choice.

Oh, wait, there is one more benefit to the 30mm tube: Manufacturers can ususally get by with charging more for them.

To get a somewhat "apples to apples" comparison of 1" to 30mm tubes you probably want to comepare similar magnification scopes from the same manufacturer. I own both 1" and 30mm tube Swaro's so in comparing the two:

The 1" tubes:
- are lighter
- cost less
- more compact

The 30mm tubes:
- Cost a good bit more
- Have more features: i.e. telescoping occulars to prevent bloody eyebrows, Lighted reticles available, rail mounts available etc.
- greater adjustment range
- have a sturdier coil spring erector system
- are superior optically
- The tubes are stronger, especially the rail mounts


Supposedly it's easier to make a 30mm lens sharper than a 1" lens since it doesn't have to bend the light as much or whatever. They may have the same glass, coatings or whatever but to my eyes there is a noticable quality difference optically in favor of the 30mm's - maybe they do use slightly better glass.
Some of the Swaro 30mm's are not nearly as heavy as you would think. A 30mm tube 2.5-10x42 Swaro is lighter than a Bushnell 4200 2.5-10x42 1" tube and quite a few others. It pays to check how much a scope really weighs before assuming that a 30mm tube is heavier.

In my book there is definately a place for both 1" and 30mm tube scopes. I think a lightweight rifle should have a lightweight scope. To me a tiny compact 3-9 would look silly on a long barreled beanfield gun. Fit the scope to the rifle and it's purpose and it will probably look right too......................DJ

Here's another reason, I recently decided to put Swarovski Scopes on my 4 main hunting rifles. I purchased two scopes to start one with 30 mm and one with 1". The 30 mm has almost 1/2" less eye relief and I had to move my head when I mounted my rifles. The 1" was perfect when I mounted the rifles.

Also on a Remington Action that I had customized had a Sako Extractor and when you cycled the gun fast the shell would hit the scope and fall back down into the magazine. With the 1" scope it ejected fine.

On top of that the 1" looks better and is lighter. Obviously the eye relief is an issue with the 30mm Swarovski because there new PV2 has the same eye relief as the 1" models.

By the way I purchased the 30 mm Swarovski a couple years ago before the big price increases and actully traded it for the same money I paid.

Good information, DJ & Tradewinds. But I think that it is not an apples-to-apples comparison of the 25.4mm vs. 30mm tubes. Just because a manufacturer chooses to build a better scope on a 30mm tube does not mean that the 30mm tube is inherently superior. As I said earlier, it will allow for a greater range of reticle adjustments, but beyond that it has no optical advantages.

quote:

Originally posted by Stonecreek:
As I said earlier, it will allow for a greater range of reticle adjustments, but beyond that it has no optical advantages.

Sorry Stonecreek but that's simply wrong. The larger a lens the easier it is to manufacture to a certain resolution. Not a big difference between 25.4 and 30mm but it is there...............DJ

In wide-ratio variable scopes with large objectives, 30mm tubes allow more of the widest field of view to be fully illuminated by the objective, yielding an image that is brighter all the way to the edge at the lowest power. This is even more important when you're not using the center of the optics because of the adjustments needed to zero the reticle on POI.

As mentioned earlier, larger lenses are easier to make accurate over the same usable aperture than smaller lenses, because the figure of the surface is hard to maintain the closer you get to the edge. Thus a 30mm diameter lense of the same overall quality has a better central 25mm region than a 25 mm lense.

For the same weight of aluminum, a 30mm tube is more rigid than a 25mm tube. The extra rigidity is not indicative of resistance to denting, which is more of a function of thickness of the aluminum. For the same wall thickness (and therefore similar resistance to denting), the 30mm tube is ~20% heavier, but much more rigid.

millimeters do matter in optics. I sell optics for surgern and a 5mm scope does not reslove quite as well as a 10mm scope but the difference is certainly not enough to prevent surgeons from using 5mm scopes. Their is also a light issue with 5mm scopes not quesite as bright as 10mm scopes but this is because of other reasons. Point is, the larger a group of lenses are, usually you will have better image period.

Sounds like soon we will see an inch and a half scope to counter the 30mm ones.

The first scope I looked thru was a cheap local hazy .22 scope, and it was so much better than open sights I've never complained about lense quality since. Give me good strong and consistant adjustments, and if I can't see when it gets dark I'll just go home.

What about straight tube scopes? Say a comparision between a 1" and a 30mm - 1.5-4x scope.

As long as the guts of the scope are true 30mm, wouldn't the 30mm have a advantage.

Rich

Not always the case, but 30mm scopes are 1st focal plane and 1" scopes are second focal plane if they are variable scopes. I prefer 1st focal plane so much so, I won't buy any other unless it is a fixed scope.

Hi

Sorry but I think a lot of you have missed the point here.

The main reason for 30mm scopes is four times magnification like the 3-12, 1,5-6 or 4-16 while american 1" scopes normally only have 3 times magnification like 3-9, 4-12 etc.

There will not come more light trough a 30mm than a 1", the light passage trough the scope is by the way normally less than 10 mm.

30 mm gives more room for elevation as well and it's probably therefor a lot of the sniperscopes today is 34mm.

1" scopes as well as 30mm and 34mm scopes comes both with first and second plane reticles.

30mm scopes does not have a bigger field of view because they are 30 mm but because they have shorter eye relif.
The field of view and the eye relif is closely connected and if you want to have big eye relif it means that your field of view will be poor.

Personnally I have been using Kahles and SuB scopes on my .358 Norma Magnum and I have never had any problem with eye relif, so for the small caliber that mostly of us uses, i cant see any good at all with long eye relif.

Zeiss 8x56 is one of the best night scopes ever and it comes with a 1" tube and so does also mostly other manufacureres fixed scope does.

Regards Sten Gun

I won't debate which is the better optically, but one good reason for 1" tubes instead of 30m/m tubes is handiness and balance of the rifle with the scope mounted. Even if both scopes are the same weight, I have found that my rifles with 30 m/m scopes on them are less handy to grab, swing, carry, stack, store, you name it. So, now I don't use anything with a larger tube than 26 m/m.

Plus...I like scopes that "look" properly proportioned to the rifle. I know that is "in the eye of the beholder", but I prefer small scopes on smaller light rifles. The only rifles I still have 30 m/m scopes on are those intended to be shot mainly from a rest of some sort, and only a few of those.

I find if I pay enough money I can get plenty good enough optical quality for even Benchrest shooting or night hunting with either diameter.

I'm with you Albert almost completely except for that I think that a 2-7x32 Lightweight looks just as silly on a 26" beanfield gun as a 4-16x50 looks on a Svelt Mountain rifle.................DJ

And I agree with you also, DJ....I too think a compact scope looks ridiculous on a large heavy gun. I was just trying to make the point that an appropriate sized scope for balance, handling, and appearance is important to me, so long as the optics are "good enough" for the specific use to which the gun is put.

Why do the Germans build their scopes in the main, on 30mm tubes

quote:

Originally posted by StenGun:
Hi

Sorry but I think a lot of you have missed the point here.

The main reason for 30mm scopes is four times magnification like the 3-12, 1,5-6 or 4-16 while american 1" scopes normally only have 3 times magnification like 3-9, 4-12 etc.

There will not come more light trough a 30mm than a 1", the light passage trough the scope is by the way normally less than 10 mm.

30 mm gives more room for elevation as well and it's probably therefor a lot of the sniperscopes today is 34mm.

1" scopes as well as 30mm and 34mm scopes comes both with first and second plane reticles.

30mm scopes does not have a bigger field of view because they are 30 mm but because they have shorter eye relif.
The field of view and the eye relif is closely connected and if you want to have big eye relif it means that your field of view will be poor.

Personnally I have been using Kahles and SuB scopes on my .358 Norma Magnum and I have never had any problem with eye relif, so for the small caliber that mostly of us uses, i cant see any good at all with long eye relif.

Zeiss 8x56 is one of the best night scopes ever and it comes with a 1" tube and so does also mostly other manufacureres fixed scope does.

Regards Sten Gun

The 8x56 Zeiss is a bloody beauty!

quote:

Originally posted by Blair D Calvin:
Why do the Germans build their scopes in the main, on 30mm tubes

Becuase they do normally build scopes with 4 times magnification changer like 1,5-6 or 3-12.
while American or asian scopes are often 3 times like 3-9 and then is the 1" tuube enogh.

Regards StenGun

quote:

Originally posted by Blair D Calvin:
Why do the Germans build their scopes in the main, on 30mm tubes

Because they hunt at night...

quote:

The main reason for 30mm scopes is four times magnification like the 3-12, 1,5-6 or 4-16 while american 1" scopes normally only have 3 times magnification like 3-9, 4-12 etc.

Really? Would someone like to explain the mechanics of this phenomenon? And does a 7/8" tube or a 3/4" tube reduce the power range further?

quote:

Originally posted by Stonecreek:

quote:

The main reason for 30mm scopes is four times magnification like the 3-12, 1,5-6 or 4-16 while american 1" scopes normally only have 3 times magnification like 3-9, 4-12 etc.

Really?

Not Really. The the quoted statement is simply incorrect. The new Redfeilds for example have a 5x magnification i.e. a 1" 3-15x52 and a 1" 5-25x52.

http://www.riflescopes.com/departments/314/rifle_scopes...eld_rifle_scopes.htm

It doesn't have anything to do with being 1" or 30mm........................DJ

European manufacturers never build 4times magnifications changers on 1" scopes and does very rarely build fixed power scopes on 30mm.

They do probably consider the space inside a 1" tube to small to get in pieces that is strong enough.

Regards StenGun

Thanks, DJ.

It seems as if the body of mythology surrounding optics often exceeds that surrounding Bigfoot or Nessie.

There are two, and only two advantages in a 30mm vs a 25.4mm tube: The larger tube can obviously be made stiffer (as if that were an issue), and the larger tube allows for a greater ranger of reticle adjustment.

YOU CANNOT "GET MORE LIGHT" THROUGH THE LARGER TUBE, NOR DOES IT HAVE ANY RELATIONSHIP TO THE RANGE OF MAGNIFICATION VARIABILITY.

Now, if someone decided to build a roof prism scope (which to my knowledge has never been done), then the physical space within the tube would certainly come into play.

Stonecreek and Dj

It's absolutely possible that you both are rigth, but what you are saying is just opposite to what Zeiss are saying.
Personally I know who I choses to belive.

And it's at least that way they are building their scopes, so there must be something in the idea about using 30mm for 4X magnification changers.


Regards StenGun

Sten, Your original statement is one of those that's usually true but not always. Most of the time the 4x's are in the 30mm tubes and probably for the reasons you mentioned later:

quote:

Originally posted by StenGun:

They do probably consider the space inside a 1" tube to small to get in pieces that is strong enough.

Regards StenGun

Next year they will probably come out with several fixed power 30mm tubes just to spite us!
The optics manufacturer that I spent some time talking to convinced me that designing optics is as much of an art as a science. IMO Zeiss, S&B, Swaro are better at the art than most............DJ