Use a scope? Please read

Mandi · November 7, 2017, 02:14 PM

Hello,

I am researching scopes and thought this would be the best place for information I am seeking.

What are the common diameter sizes for eye pieces? Does the dimension pertain to inner diameter (glass) or outer diameter (housing)?

The amazon link from UTG shows multiple sizes but are these correct?

https://www.amazon.com/dp/B00WQSMGC4..._svFaAb8B3EE8A

Sincerely,
Jonathan

Dufus · November 7, 2017, 03:30 PM

When a scope specifications are 3-9x50, the 50 refers to the diameter of the glass (50mm in this instance).

You would need to go to the manufacturers website to see the specifications on the eye piece.

Here is an example for a Leupold scope. Look at the "Dimensions" tab for an outline drawing.

https://www.leupold.com/scopes/compa...5x56mm-cds-zl2

lefteye · November 7, 2017, 03:40 PM

The last number is the diameter of the objective lens, i.e., the lens at the front end of the scope. If the scope is variable power, the objective lens diameter will be the third number in the description of the scope specifications. Leupold's website seems to indicate the eye-piece diameter is the outside diameter of the scope at the eye-piece.

OzeanJaeger · November 7, 2017, 04:26 PM

...which is kind of irrelevant. The ocular lens just puts the objective and focal image together for your eye. It’s size doesn’t matter as long as it creates a comfortable eye relief. There is a “right” size for the ocular lens and larger or smaller would make it worse. You rarely see any specs for them because they’ve generally gotten that part right.
It’s the objective lens that increases the scopes ability to gather light. The bigger the objective the brighter the scope in low light conditions and the less light you loose under extreme zoom.

The best way to experience this is with a large (80mm) spotting scope with a high zoom at dusk. As you zoom in you can really tell the immage gets darker as you narrow the field of view.

November 7, 2017, 02:14 PM	#1
Mandi Junior Member Join Date: November 7, 2017 Location: Phoenix Posts: 1	Use a scope? Please read Hello, I am researching scopes and thought this would be the best place for information I am seeking. What are the common diameter sizes for eye pieces? Does the dimension pertain to inner diameter (glass) or outer diameter (housing)? The amazon link from UTG shows multiple sizes but are these correct? https://www.amazon.com/dp/B00WQSMGC4..._svFaAb8B3EE8A Sincerely, Jonathan

November 7, 2017, 03:40 PM	#3
lefteye Senior Member Join Date: January 30, 2006 Posts: 1,433	The last number is the diameter of the objective lens, i.e., the lens at the front end of the scope. If the scope is variable power, the objective lens diameter will be the third number in the description of the scope specifications. Leupold's website seems to indicate the eye-piece diameter is the outside diameter of the scope at the eye-piece. __________________ Vietnam Veteran ('69-'70) NRA Life Member RMEF Life Member Last edited by lefteye; November 7, 2017 at 03:59 PM.

November 7, 2017, 03:30 PM	#2
Dufus Senior Member Join Date: December 10, 2014 Posts: 1,965	When a scope specifications are 3-9x50, the 50 refers to the diameter of the glass (50mm in this instance). You would need to go to the manufacturers website to see the specifications on the eye piece. Here is an example for a Leupold scope. Look at the "Dimensions" tab for an outline drawing. https://www.leupold.com/scopes/compa...5x56mm-cds-zl2

November 7, 2017, 04:26 PM	#4
OzeanJaeger Senior Member Join Date: September 8, 2014 Posts: 301	...which is kind of irrelevant. The ocular lens just puts the objective and focal image together for your eye. It’s size doesn’t matter as long as it creates a comfortable eye relief. There is a “right” size for the ocular lens and larger or smaller would make it worse. You rarely see any specs for them because they’ve generally gotten that part right. It’s the objective lens that increases the scopes ability to gather light. The bigger the objective the brighter the scope in low light conditions and the less light you loose under extreme zoom. The best way to experience this is with a large (80mm) spotting scope with a high zoom at dusk. As you zoom in you can really tell the immage gets darker as you narrow the field of view.