30mm or 1"
 

Why would I choose a 30mm over a 1" scope? I do not really understand the difference. Is one stronger than the other? Why do they make both?

Thanks for the help

30mm has more windage and elevation adjustments usually.

They say 30mm is stronger than 1"

Europeans had 30mm all along I believe, and Americans always had 1".

30mm do not let more light through.

Usually for me 30mm or 1" is a side note of the scope I like...

I own both and like both, having more adjustments for windage and elevation is nice though.

Totally false. Anything you can do to open the passage of light in between the objective and ocular lens, helps.

I'm not an expert but have read that the human eye pupil only allows so much light in and anything over that amount does nothing to enhance your low light view. Bottom line is that a 1" scope to that allows the maximum amount of available light thru is just as bright as a 30mm that does the same. Don't know but read from others who do.

It is also said that a high end 1" scope is far and away better than a lower end 30mm, not only for light transmission but overall.

In my hunting and shooting I have not found the need to change from 1" from which I have many, to 30mm from which I have none.

Yea, thats what John Barsness and Spooner (gun writers) say. But what they are not telling you is, thats ideal lenses. In other words, no imperfections. Larger internal lenses allow for more slop. This is fact.

According to cabelas scope buyers guide...

Tube Diameter: The majority of the scopes on the market come with the main tube having a one-inch diameter. Several European models and now a few others also come with a 30mm tube diameter. Contrary to popular belief, the larger tube does not allow more light to reach your eye. The exit pupil mentioned above controls this. However, a larger tube diameter does give added strength and rigidity due to the greater cross sectional area and larger rings and mounts. A larger tube diameter also allows for an increased range of adjustment for windage and elevation.

click on the buyer's guide to read more...if you want.
http://www.cabelas.com/cabelas/en/te...set=ISO-8859-1

Nope, I pretty well will just rely on my education and designs in optics. But hey, you got cabelas. Go for it.

Bigcountry, Sorry, but I will rely on the optical experts from Leupold. This is directly from their website:

The Leupold Answer Guide

Advantages of a 30mm Maintube
Does a 30mm main tube give you more light? The principal advantages of the 30mm tube are added strength and increased adjustment range for windage and elevation. For example, the M8-12X (1" main tube) has a total elevation adjustment of 51 minutes. The Mark-4 M1-10X (30mm main tube) has 90 minutes. The percentage of light passing through a scope is a function of lens coating and optical design, and has nothing to do with tube diameter.

I assume that Leupold does have some valid expertise in scope design.

Go for it man. Have a ball.

Yep, thats straight out of Phyics of Light 101 book I studied 20 years ago in college. Almost word for word. But as usual, experience cannot be bought in this case. There is a lot more to it. With ideal lenses, and a perfect design, this is absolutely correct. Too bad ideal shaped lenses and medium are not cheap.

And you are missing a key component to leupold's answer. Guess what? They don't use 30mm lenses in any of thier 30mm scoped products. 1", just like thier 1" scope. But I guess you knew that. Think there would be any marketing advantage to exploit that 30mm internal lenses are no better than 1" internal? Think 1" lenses are 30% smaller polishing area than 30mm lense. Think there is any price advantage to exploit that 30mm internal lenses are no better than 1" internal?

all I know is I want to upgrade to a Leupold 6.5 X 20 and it looks like I got to buy new 30mm rings to do it.