Home Forums Hunting & Shooting Ask The Gunwriters Why has everyone gone ape over larger, i.e. 50mm, objective lens on scopes?

Actually "Gathering Light" is exactly what any telescope including riflescopes does. Read into a few serious references to Astronomical riflescopes and Birding binoculars and "Light Gathering" will be specifically mentioned.
Someone in the firearms business incorrectly put the word out that scopes don't "Gather Light", simply put they were wrong, the term is commonly used my several other optical disciplines.....................................DJ

....... Rifle scopes do "gather" light, just as telescopes do. The light photons entering the objective lens are transmitted through various lens, which magnify and ultimately condense them into the exit pupil diameter that is available to the users eye. This process of collecting light from a larger objective lens and magnifying the received image while concentrating it as a beam of light has long been referred to as "gathering" light, a better description of this optical process has yet to be found.

Rifle scopes, binoculars and spotters do not gather light in the technical sense of the term. They transmit whatever amount of incident light that falls onto their objective lenses. This term, "gathers light" has been misused in the sporting optics industry and advertising. Even night vision optics only magnify the amount of incident light available. Rifle scopes, binos and spotters are passive instruments.

As RD, stated so eloquently scopes do not gather light and that is a fact..

You are correct... One can gather fruit, nuts, etc. but a scope only passes the light that enters into it's objective, the scope does not go out and gather more. The larger the objective the more light that is able to pass through the scope

You guys need to do a little more research. You are dead wrong.

From the Encyclopedia Britannica:

Optical telescopes � Light gathering and resolution
The most important of all the powers of an optical telescope is its light-gathering power. This capacity is strictly a function of the diameter of the clear objective�that is, the aperture�of the telescope. Comparisons of different-sized apertures for their light-gathering power are calculated by the ratio of their diameters squared; for example, a 25-centimetre objective will collect four times the light of a 12.5-centimetre objective [(25 � 25) � (12.5 � 12.5)] = 4. The advantage of collecting more light with a larger-aperture telescope is that one can observe fainter stars, nebulas, and very distant galaxies


From: http://www.telescopes-astronomy.com.au/telescopes012.htm

The larger a telescopes aperture (size) the more light gathering power and better resolution it has.


From Cornell University's Ornithology Lab:

To a birder, binoculars' light-gathering capacity is nearly as important as image sharpness. Only a bright image reveals subtle field marks and the full beauty of bird colors.


etc. etc. etc.


It's simply RifleScopes are telescopes, they "gather light" just like any other telescope or binocular. If you claim they don't you are simply WRONG. The slightest bit of study in any optic field will prove this beyond any shadow of doubt, claiming otherwise is just being stubborn and ignorant.............................DJ

Then I guess ILya Koshkin is stubborn and ignorant on this topic

So you are saying that the scope gathers a bit of light, continues on down the trail to gather more? I think not.


Main Entry: 1gath�er
Pronunciation: \ˈga-thər also ˈge-\
Function: verb
Inflected Form(s): gath�ered; gath�er�ing \ˈgath-riŋ, ˈga-thə-\
Etymology: Middle English gaderen, from Old English gaderian; akin to Middle High German gadern to unite � more at good
Date: before 12th century
transitive verb
1: to bring together : collect <tried to gather a crowd> <gathered firewood>
2 a: pick , harvest <gather flowers> b: to pick up or amass as if by harvesting <gathering ideas for the project> c: to scoop up or take up from a resting place <gathered the child up in his arms>
3: to serve as an attraction for : accumulate <books gathering dust>
4: to effect the collection of <gather contributions>
5 a: to summon up <gathered his courage> b: to gain by gradual increase <gather speed> c: to prepare (as oneself) by mustering strength d: to gain or regain control of <gathered his wits>
6: to reach a conclusion often intuitively from hints or through inferences <I gather that you want to leave>
7 a: to pull (fabric) along a line of stitching so as to draw into puckers b: to draw about or close to something <gathering her cloak about her> c: to bring together the parts of <gathered her hair into a ponytail> d: to assemble (the signatures of a book) in sequence for binding e: to haul in <the sailors gathered the sails>
intransitive verb
1 a: to come together in a body b: to cluster around a focus of attraction
2 a: to swell and fill with pus b: grow , increase <the gathering crisis>
� gath�er�er \-th&#601;r-&#601;r\ noun
synonyms gather , collect , assemble , congregate mean to come or bring together into a group, mass, or unit. gather is the most general term for bringing or coming together from a spread-out or scattered state <a crowd quickly gathered>. collect often implies careful selection or orderly arrangement <collected books on gardening>. assemble implies an ordered union or organization of persons or things often for a definite purpose <experts assembled for a conference>. congregate implies a spontaneous flocking together into a crowd or huddle <congregating under a shelter>.
synonyms see in addition infer

http://www.merriam-webster.com/dictionary/gather

DJ is correct.

-Bob F.

Keep trying. Try reading articles about other types of optics and you'll see that the term is in quite common use. Just Google "light Gathering" and read the non-religious threads and you'll see it over and over again. It's a standard term and not hard to find if you'll just take a few seconds to look........................................DJ

One more time:


"The ability of a telescope to collect a lot more light than the human eye, its light-gathering power, is probably its most important feature. The telescope acts as a "light bucket", collecting all of the photons that come down on it from a far away object. Just as a bigger bucket catches more rain water, a bigger objective collects more light in a given time interval. This makes faint images brighter. This is why the pupils of your eyes enlarge at night so that more light reaches the retinas."
http://www.astronomynotes.com/telescop/s6.htm
http://users.zoominternet.net/~matto/M.C.A.S/powers%20of%20a%20telescope.htm#Powers%20of%20a%20Telescope


-Bob F.

Just because you can "google" a term does not mean it is being used correctly. If a riflescope or binocular could gather light, could it then transmit more light than what is available?

It could if it could gather.. Many appear to support the misuse of the word..

A 10x50 scope transmits a 5mm shaft of light. Was there only a 5mm shaft of light available at the front of the scope?.................Dj

No, that is the function of the optic. If there were 100 lumens of light available in front of the objective lense, could the objective "gather" a 120 lumens of light to increase the percentage of incident light available?

Exactly. It gathers the 50mm shaft of light into a 5mm shaft of light. It doesn't create something out of nothing, nor does any definition of gathering include something that isn't there!..........................................DJ

I think perhaps we are just confusing the terms "gather" and "transmit" then.

IIRC the confusion started with Leupold in one of their "Scope Fact" sheets. They are the first ones that I recall claiming that scopes "transmit" rather than "gather" light. I guess it's really nothing more than a pedantic arguement but the term "Gathering Light" has been used for quite a while in describing the operation of Telescopes and other optics in General. I think that the "transmitting" arguement was pretty much an advertising ploy to emphasize the % of light transmission figures of a certain brand of scopes, whether or not it was against the normal usage of the term.
Again I realize it takes a while to sink in and it's hard to change something that you've been told for a while. But I really do think if you'll read some of the articles from extremely solid sources (Encylopedia Britannica, etc.) easily found by using Google, Yahoo, Ask or other search engine, you'll begin to see that "Light Gathering" is a standard term used in referring to Telescopes and binoculars.................................DJ

Kinda like the term "eyebox".......................grin

I guess it must be a regional thing because I have noticed the reverse even on here, more and more are shying away from the larger OBJ scopes.

Most of the shops won't even stock the 50mm scopes because they just can't sell them.

I would bet that in the classifieds if you had a 3-9X40 and 3-9X50 of the same make and model at the same price that the 40 would sell faster more often than not...