Objective Bell Size and Optics

[Whitey66]

Been doing some thinking lately about scopes with making a purchase and crossed this thought. It is concerning scope brightness and clarity. Many people say that the bigger the objective bell, the more light the scope will gather. Others say its not so much the bell size as it is a good optic scope with great clarity. I think it is both myself but wondering to which degree you can gain the most light from or shall I say perceived light(scope clarity)? I see many people with higher end scopes but with less power and bell size. Like alot with fixed power or variable x32mm scopes. Then some with cheap, low end scopes with huge 50mm bells on the end to try and acheive the same thing. Which is most critical to get you where we all want to be? Size or Quality?

[Graybeard]

No optical instrument ever invented to date GATHERS light. All the do is TRANSMIT light.

How effectively and efficiently they do this depends on a lot of factors the least of which is the size of the objective lens. Rifles mounted with scopes with HUGE objectives are a sure sign of an uneducated shooter/hunter or a magazine writer using what the sponsors want pitched at the time.

The concept of the over one inch scope tube and larger than 40-42mm objective originated in Europe. For them it has a purpose. They have no set hunting hours. As long as it's light enough for them to see the game they can hunt it even at night. So a scope that has a huge tube and enormous objective allows them to jack up the magnification and bring game in closer while still not losing the image to a too small exit pupil.

So now lets talk the next important thing and that's exit pupil. The normal human eye on a young person can expand to at most 7mm and on us older types we're lucky if it goes 5 mm. So we see less light and think we need more. But in reality an exit pupil over 5mm is wasted on the normal hunter as far as how bright it makes the image appear. It does have other beneficial aspects such as allowing more lattitude for eye movement side to side and up and down before you lose the image as it blacks out on you. I think but am not sure that is what some folks have come to call an "eye box" a term that never existed in Optical Theory until recently when either some magazine writer or scope maker coined it.

So what you want is a scope with extremely high quality optical glass properly matched to each other with multi coating on all those lens. But it still goes way beyond that. It's how the thing is made and put together as the mechanical aspects are just as important as are the optical aspects. Otherwise it will never hold zero.

Get a scope with solid mechanical reliability and that passes 90% or more of the light with an objective lens large enough so that at the maximum power range you plan to use in low light you have an exit pupil of 5mm or more and you have all the scope you need. And for big game hunting anything over 9X is wasted and again more a sign of an uneducated hunter than anything else. Save the 12X and over magnifications for the varmints and target range.