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Technical Objective size question

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 06:01
Mike52 View Drop Down
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Given 3 variable scopes of identical manufacture, glass, coatings, quality etc.  one having a 56mm objective, one having a 50mm objective and one having a 42mm objective all set at 4X the optical calculation for exit pupil says that at that 4X the exit pupil's will be 14 mm, 12.5mm and 10.5mm respectively.  All of which are larger than the maximum 7mm dilation of the normal human eye in the dark. 

If all your hunting is on big game under 100 yards and you never set your scope over 4-5X what if any is the point in a 50 or 56mm objective? 





  
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 06:58
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IMO, no point for the big Hubble-like scopes based on your scenario.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 11:14
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At 4x or 5x, a 32mm or 35mm objective will work as well as anything.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 11:38
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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 11:46
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It has been posted by night time hog hunters that big objectives do help all else being equal.

One particular brand that is talked about is the Trijicon Accupoint 3-9x40 vs the 2.5-10x56.  Those that have both do say the 56 is brighter and more usable at night and in low light.  But most of them prefer the 3-9x40 because it is lighter and smaller.  
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 12:00
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Originally posted by supertool73 supertool73 wrote:

It has been posted by night time hog hunters that big objectives do help all else being equal.

One particular brand that is talked about is the Trijicon Accupoint 3-9x40 vs the 2.5-10x56.  Those that have both do say the 56 is brighter and more usable at night and in low light.  But most of them prefer the 3-9x40 because it is lighter and smaller.  
There is one fellow who reported here that (in his experience,) none of the 1x..-24mm objective scopes are as usable in low light as scopes with larger objective lens.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 12:10
Mike52 View Drop Down
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it is puzzling as some claim the big objectives help (all else being equal) but other's see no difference.  The technical argument says they would not be of much help provided the exit pupil was all that it took to illuminate your eye pupil.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 12:26
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A bigger objective makes a big difference, but not at 4X. A 50mm objective lens lets twice as much light into the scope than a 35mm lens. To take advantage of that light, you have to adjust the magnification so the exit pupil of the scope is equal to the entrance pupil of the eye.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 12:35
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There is no doubt the larger objective allows more light to enter the scope.  Exit pupil size is not the "final arbitor" of "apparent brightness".  Your question is too generic and relative... there are a number of variables that come into play and can't really be addressed based upon your question parameters.  Volumes could be written, and have been, on this type of scenario. 
Based upon your stated requirements, the smaller objective should provide all the "brightness" you need.  That does not translate to other, more complex, scenarios
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 12:51
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Being able to "zoom" in closer on the game will make it appear brighter as well as you will be able to see more detail because of the added magnification.  This is another area where a larger objective will make a difference as you will have a larger exit pupil.

Hopefully Charles "ccoker" will comment on this as he has a lot of in the field experience in low light and night hunting with a large number of scopes high quality scopes. 

Quote it is puzzling as some claim the big objectives help (all else being equal) but other's see no difference.  The technical argument says they would not be of much help provided the exit pupil was all that it took to illuminate your eye pupil.


This is always one of the difficulties with asking these types of questions.  First off we have no real idea if said person has any idea what to look for.  Are they really using comparable scopes.  Was the small objective scope a Swaro and the large objective a Bushnell 4200?  Do they really understand the technical aspects of the question?

I admit my technical knowledge is very limited vs people like Kickboxer, Koshkin, Rifledude, etc. 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 14:18
Mike52 View Drop Down
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I cannot see how my question would be generic? 3 scopes of identical glass and coatings but with different objective sizes? Say 3 Zeiss victory scopes 1-4 x25, 1.5-6 x42, and 2.5-10 x50 all manufactured on the same day at the same time. All set at 4x. Do I know what to look for, yes for an image as the lights go off. I am getting the answer that it is more of a feeling than a hard fact regards this question.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/30/2013 at 14:25
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You might find it informative to run those numbers through the Low-Light Performance Calculator at scopecalc.com.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/01/2013 at 04:47
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Is there a relationship between objective size and FOV ? I ask because I don't know.

I know FOV has a big impact on my 'perception of usefulness' with many scopes.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: October/31/2013 at 21:44
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Here is one easy advantage you can state without a doubt for bigger objectives:
The bigger the objective the greater the ability to resolve detail of the viewed object.

Cheers,

Tye
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