Can anyone offer an explanation as to why there are different rifle scope tube sizes? I have noticed that there are predominantly two sizes offered, 1" and 30mm. Are there other common/uncommon size scope tubes and why/what is there a difference between the sizes. Just curious as i often see a scope that may be of interest but the tube size is 30mm and all my rings are 1". Thanks for any information offered, Ken Watts.
different scope tube sizes
- Thread starter op-dog
- Start date
- Location
- Winnipeg,Man.
Metric system and also sales . 30 mm size requires new rings...more sales
Nope, 30mm tubes don't effect light transfer, field of view, or exit pupil. They MIGHT offer more internal adjustment if they are set up that way, allow room to put a side paralax adjustment, and will give considerably more strength for supporting large bells that are just begging to bend tubes. And they look cool.
Nope, 30mm tubes don't effect light transfer, field of view, or exit pupil. They MIGHT offer more internal adjustment if they are set up that way, allow room to put a side paralax adjustment, and will give considerably more strength for supporting large bells that are just begging to bend tubes. And they look cool.
All things being equal dimension wise... they do!
No, you should read a book or something.
Larger tube = larger lenses = more light = larger field of view = better exit pupil (Dimensional equivalence as a percentage of size 30mm vs 25mm the surface area on the lenses is greater)
Burris Technology
Burris uses lenses with a greater diameter than the competition
• “Signature Select” scopes lenses are 40% larger than the competition in 1” tubes
Exit pupil = Objective lens divided by magnification. period
Field-of-view is a function of magnification and the focal lengths of the objective and eyepiece lenses.Mostly magnification.
If it was that simple the values (specs) would be constant between all manufacturers models of 1-4 scopes, (all things being equal dimension wise) a 30mm tube allows for a larger lens, a larger lens within this constriction provides ... (see grade 1 science experiment below)
Grade 1 science experiment.
Poke a 1mm hole in a piece of cardboard
Poke a 2mm hole in a piece of cardboard
Take the 1mm piece, hold 3 inches away from your eye, look thru hole at object 200 yards away.
What can you see?
Repeat steps using 2mm piece of cardboard.
Is the sight picture any different?
Repeat 15 minutes after the sun sets.
What are your observations?
Lmao..I don't have time to wait til sunset, but can tell you that area = pi R squared so in practical terms means that the area of a 2mm hole is 4 times that of a 1mm hole. Both have zero to do with the size of the pipe. What else ya got?
Hey I just figured out where the wheels fell off your wagon. If you are looking at straight tubed 1-4 and similar variables, then the size of the tube also determines the size of the Objective lens. A straight tubed 30mm scope has a bigger objective lens than a straight tubed 1" scope, and hence will have a larger exit pupil. The larger EP is a product of the larger lens, and as you are fond of saying, all is no longer equal.
Shall we move on to field of view?
If you are looking at straight tubed 1-4 and similar variables, then the size of the tube also determines the size of the Objective lens. A straight tubed 30mm scope has a bigger objective lens than a straight tubed 1" scope, and hence will have a larger exit pupil. The larger EP is a product of the larger lens, and as you are fond of saying, all is no longer equal.Shall we move on to field of view?
I thought exit pupil was only a function of objective/ocular? If so then the extra dia of the tube has little to do with light transmission. I thought the major benefit of the 30mm tube was it allowed for more elevation/windage adjustment and perhaps a slightly stronger tube. Some of Leupolds 30mm tubes have 70-90MOA adjustment.
If the lenses inside the 30mm tube are the same diameter as the ones in the 1" tubes, then there is little advantage in efficiency of light transmission to be gained. So, you guys are right, 30mm isn't necessarily brighter.
