Which has more influence on collecting light in low light conditions (dawn and dusk), the size of the scope (40mm or 50mm) or the size of the tube, 30mm vs 1 in tube. Will a 40 mm w a 30 mm tube collect as much light as a 50 mm with a 1 inch tube. Just pondering the question.
Quick scope question
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MudRunner2005
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Both... The bigger objective gathers more ambient light, and the bigger tube has larger lenses in it, which transfers more light. So the bigger the tube and the bigger the objective, usually the brighter and clearer the image will appear, because the image you see in your scope, is nothing more than reflected light.
Another advantage to a larger tube, is more reticle adjustment, so that is also something to consider when purchasing a scope. If you plan on dialing and shooting long range, a 30mm tube is usually the starting point.
Another advantage to a larger tube, is more reticle adjustment, so that is also something to consider when purchasing a scope. If you plan on dialing and shooting long range, a 30mm tube is usually the starting point.
Wedgy
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Mudd, I've read countless times the tube has no bearing on amount of light transmission, just windage & elevation. Correct or not I don't know, but I have read it again and again.
The bigger the objective(front lens nearest the muzzle) the more light collected. How much light making it to your eye depends on the power magnification of the scope(and the glass quality, assuming the same for comparison purposes).
The amount of light coming out of the scope is "exit pupil"
EP = objective divided by magnification power
50mm objective at 10x = 5.0mm exit pupil
40mm objective at 10x = 4.0mm exit pupil
A 50mm objective will give 25% more light than a 40mm, given all else equal in the scopes. That's my understanding anyway.
The bigger the objective(front lens nearest the muzzle) the more light collected. How much light making it to your eye depends on the power magnification of the scope(and the glass quality, assuming the same for comparison purposes).
The amount of light coming out of the scope is "exit pupil"
EP = objective divided by magnification power
50mm objective at 10x = 5.0mm exit pupil
40mm objective at 10x = 4.0mm exit pupil
A 50mm objective will give 25% more light than a 40mm, given all else equal in the scopes. That's my understanding anyway.
Capt RB
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Obj lense size of the same quality bigger will transmit more light and provide better res because of that extra amount of transmission.
Obviously a top end 40mm will have better color fidelity contrast edge to edge sharpness etc etc than a entry level glass.
Obviously a top end 40mm will have better color fidelity contrast edge to edge sharpness etc etc than a entry level glass.
WildRose
Well-Known Member
The objective diameter is what limits light gathering. The tube diameter limits vertical and horizontal adjustment.
Nearly all high quality scopes are going to have close to 99% light transmission so in low light it's all about the objective diameter and coatings.
WildRose
Well-Known Member
Light is at it's brightest when focused tightly. Think about when you were a kid playing with a magnifying glass in the sun.
MudRunner2005
Well-Known Member
Different grinds on the lenses can direct the light, too, regardless of lens diameter.
WildRose
Well-Known Member
Grinding won't increase the surface are by any significant amount. The grinding has more to do with clarity and focus.
A given diameter objective can only collect and transmit so much light even if you had glass capable of 100% light transmission (which of course doesn't exist).
MudRunner2005
Well-Known Member
If you grind in a deep convex (central thickness), then yes, it will increase surface area, but like you said, not by an significant amount. And polishing has to do with clarity and focus.
WildRose
Well-Known Member
Concave and Convex both increase surface area by only a very small percentage.If you grind in a deep convex (central thickness), then yes, it will increase surface area, but like you said, not by an significant amount. And polishing has to do with clarity and focus.
Polishing is part of the grinding process. You polish by using ever finer abrasives.
SansSouci
Well-Known Member
WildRose
Well-Known Member
No, that is incorrect.
On Riflescopes
The 4 Best Low Light Scopes
Rifle Scopes Reviews By Expert Hunters - 2015
http://www.shootingtimes.com/optics/optics_leaupoldvx_l_040706/
The objective gathers, concentrates, and transmits light.
The diameter of the objective limits how much light can be gathered and concentrated.
The quality of the glass, grinding, and coatings determine how much of that light will be transmitted.
This is true whether you are talking about a rifle scope, spotting scope, telescope, or magnifying glass.
A scope is not like a window. A window does one thing, it transmits light.
