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F.O.V. question

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/10/2008 at 19:42
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Why do these two scopes made by the same company and being the same power have different a field of view?

Burris 1.5-6x40 Signature Select
Field of View @ 100yds (ft): 71 - 20
Burris 1.5-6x40 Euro Diamond
Field of View @ 100yds (ft): 60 - 20
 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/10/2008 at 19:56
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 Optical Triangle.  If those specs are accurate, then the Euro-Diamond has more eye-relief than the other.
 
 Eye-Relief.  Magnification.  Field of View.
 
 Within an optical device of a given size, when one of those factors is increased, one or both of the others must decrease proportionately.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/10/2008 at 19:58
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The old optics compromise.

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/10/2008 at 20:30
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That's the problem, when I looked at the specs the eye relief for both is 3.5-4". The SS is a shorter scope, though.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/10/2008 at 20:38
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Here are the specs that swfa gives for them.  The eye relief is the same.  The only difference I can see is the length.  I can't understand why the exit pupil would be different either. 
 
Burris 1.5-6x40 Signature Select
Length (in): 11.3
Eye Relief (in): 4 - 3.5
Exit Pupil (mm): 15 - 4.5
Burris 1.5-6x40 Euro Diamond
Length (in): 12.6
Eye Relief (in): 4 - 3.5
Exit Pupil (mm): 26 - 7
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/10/2008 at 20:41
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SWFA probably uses information supplied by the manufacturers. I've been using Burris scopes for years and their published data has been wrong a bunch.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/10/2008 at 22:18
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 Yeah, the specifications seem to be approximations. I think this is typical for all manufacturers.  Think about it.  If, for example, a certain scope had an eye relief of 3.777654 inches the ad agency would just say "3.5-4 inch eye relief"...
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/11/2008 at 00:39
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I do not know if the specs are correct, but there is nothing particularly off if they are.  They are likely to have two different optical systems.  Most scopes have some exit pupil vignetting at lower magnifications, and Euro Diamond's optical system, presumably has less of it.  Same goes for field of view: while eye relief has loose inverse dependence on field of view, a system can be intentionally designed for lower field of view with the same eye relief with a resultant improvement in resolution, for example.

Then again, the specs could be simply wrong.

ILya
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/11/2008 at 09:38
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Koshkin,
  I'm not sure I understand what you said, but are you saying the Euro diamond would be better at lower magnification?  Thanks, Ben
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/11/2008 at 12:38
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Originally posted by catt_tracker catt_tracker wrote:

Koshkin,
  I'm not sure I understand what you said, but are you saying the Euro diamond would be better at lower magnification?  Thanks, Ben


The gist of what I said is that since the two scopes are likely to have different optical design, we can not make any bold predictions without comparing them.  I would expect Euro Diamond to be a bit better, but I have not compared the two side by side.

ILya
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/11/2008 at 20:46
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Originally posted by koshkin koshkin wrote:

I do not know if the specs are correct, but there is nothing particularly off if they are.  They are likely to have two different optical systems.  Most scopes have some exit pupil vignetting at lower magnifications, and Euro Diamond's optical system, presumably has less of it.  Same goes for field of view: while eye relief has loose inverse dependence on field of view, a system can be intentionally designed for lower field of view with the same eye relief with a resultant improvement in resolution, for example.

Then again, the specs could be simply wrong.

ILya
 
  You stated that most scope have some exit pupil vignetting at lower magnifications.  Is there such a thing as a scope that is to low of a power?  I am putting the scope on a new light weight rifle that will be used in heavy timber for quick snap shots.  I don't have the option of using open sights as the rifle doesn't have any.  What scope would you recommend?   I won't be using this rifle for anything over 200 yards and most likely 100 yards or less on running game.  Thanks, Ben
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/11/2008 at 23:41
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I am not aware of a scope with too low of a power, if I understand your question correctly.  For what you need, I think some sort of a low range variable will work fine, and in truth there is a large number of these scopes from many manufacturers that all work well.

For quick target acquisition on game that is not too far away, you have to look very carefully at the reticles.  I have been playing with four low magnification scopes lately: Millett DMS-1 1-4x24 with Illuminated Donut-Dot reticle, Bushnell Elite 4200 1.25-4x24 with #4 reticle with illluminated dot, Kahles C 1.1-4x24 with #4 reticle in FFP and Kahles CSX 1.1-4x24 with Cirdcle-Dot reticle in SFP.

In my hands, reticles with a dot or crosshair inside a fairly large circle are just plain faster than the #4, while #4 allows for more precise aiming.  Also, for faster shots illumination is not a bad thing especially if the light is poor.

Depending on how much money you want to spend I would recommend Millett DMS-1 on the low price end and Kahles CSX with Circle-Dot on the high price end (check the samplelist if you decide to go with the Kahles they have some very good prices).

All in all, some sort of a 1-4x24 or 1.75-5x32 with a thick and visible reticle would work nicely.  With a low magnification scope you do not really need a large objective lens.

Some options in roughly ascending price order, capping off at about $1000 with samplelist pricing:
Millet DMS-1 1-4x24 with Donut Dot
Bushnell Elite 4200 1.25-4x24 with #4
Burris Signature Safari 1.75-5x32 with #4 or taper plex
Leupold VX-3 with #4 or circle-dot
Burris Euro Diamond 1-4x24 with #4
Trijicon Accupoint 1.25-4x24
Zeiss COnquest 1.8-5.5x38 with #4 reticle (this a little larger that I like)
IOR 1.1-4x24 Hunting with #4a
Meopta Meostar 1-4x24 with K-Dot
Kahles CSX 1.1-4x24 with Circle-Dot
Swarovski PH 1.1-4x24 with Circle-Dot

ILya
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/12/2008 at 12:48
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Koshkin,
  Thanks for the help I will give them a look.  Ben
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/12/2008 at 13:41
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  Where is the Millett DMS scope made?  Do you have any pictures of the reticle?  I looked at the scope picture on SWFA, but it didn't show the reticle. 
  Where did you find the Bushnell Elite 4200 1.25-4x24 at?   I can't seem to find one anywhere.  Is it smaller than their 1.5-6?  Thanks, Ben
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/12/2008 at 23:47
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Millett DMS-1 is made in China.  For a look at the reticle, check Millett's site: www.millettsights.com

I bought my Elite 4200 through a friend who got it directly from Bushnell.  I have seen a couple of dealers have it a while back.  Pehaps you should give SWFA a call and see if they can get their hands on one.  In this picture, ELite 4200 is on the left and DMS-1 is on the right:





Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/13/2008 at 10:27
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I looked on SWFA's website,but they don't sell the Bushnell.  I will call them tomorrow and see if they can order one.  I like the looks of the scope mounted on your AR.  How do you like yours so far?  Optically and general quality? Thanks, Ben

 
 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/14/2008 at 00:28
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Originally posted by catt_tracker catt_tracker wrote:

I looked on SWFA's website,but they don't sell the Bushnell.  I will call them tomorrow and see if they can order one.  I like the looks of the scope mounted on your AR.  How do you like yours so far?  Optically and general quality? Thanks, Ben

 
 


I like mine quite a bit.  I am comfortable with modest magnification, so this scope fits me well.  So far it has been exemplary both optically and mechanically.  The reticle is thick and visible (#4) and the illumination is properly designed to work well in low light.

ILya
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