Scopes -- Okay, I'm confused again!!
I was just about to order a scope for my slug gun when I read some information on it that really has me confused. The scope is the new Bushnell Banner Cantilever Slug Gun Scope:
http://bushnell.com/products/riflescopes/banner.html
I like this scope because it has extra eye relief (6 inches) and is low-powered, which I understood was supposed to allow for a wide Field of View. I am confused, however, because the Bushnell web site lists the FOV as 35'@1.75x 16'@4x (at 100 yds). If this is correct then the FOV is only about half as wide as all other scopes with similar magnification. Also, if the stats are correct then it actually has a smaller FOV than the 3-9X40 model that has 6" ER. That just seems to make no sense at all.
I called Bushnell about it, but of course the customer service person didn't know anything. Said she'd check and call me back next week. Bass Pro's listing for the scope show's the FOV to be 73'/30', which mucks up the matter even more.
Anyhow, if someone can help me out with this I'd really appreciate it. I sure wouldn't want to order a 1.75-4 power scope that has a FOV smaller than a 3-9X40 (whats the point?)
http://bushnell.com/products/riflescopes/banner.html
I like this scope because it has extra eye relief (6 inches) and is low-powered, which I understood was supposed to allow for a wide Field of View. I am confused, however, because the Bushnell web site lists the FOV as 35'@1.75x 16'@4x (at 100 yds). If this is correct then the FOV is only about half as wide as all other scopes with similar magnification. Also, if the stats are correct then it actually has a smaller FOV than the 3-9X40 model that has 6" ER. That just seems to make no sense at all.
I called Bushnell about it, but of course the customer service person didn't know anything. Said she'd check and call me back next week. Bass Pro's listing for the scope show's the FOV to be 73'/30', which mucks up the matter even more.
Anyhow, if someone can help me out with this I'd really appreciate it. I sure wouldn't want to order a 1.75-4 power scope that has a FOV smaller than a 3-9X40 (whats the point?)
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When the engineers design a scope, they can design it to have a wide field of view, or long eye relief, but usually not both. In other words, you can have one, but not the other. This is another reason why shot gun scopes with long eye relief should be in the lower magnification ranges.
From my experience with scopes from various manufacturers, they must not all determine their specifications in the same way. It's either that, or I think they're fudging their numbers, because their data doesn't always work out as published for me. I'm not picking Bushnell out for criticism because I have several of their scopes, and I like them, but this seems to apply to many of the manufacturers.
I have both a Bushnell Trophy 1.75-5x32mm and a Leupold VX-II 2-7x32mm shotgun scope. They both work out fine for me in hunting wooded and brushy areas.0 -
quote:Originally posted by Raoul
When the engineers design a scope, they can design it to have a wide field of view, or long eye relief, but usually not both. In other words, you can have one, but not the other.
If that is the reason, then what explains why the 3-9x40 with 6" Eye Relief has a greater F.O.V. than the 1.75-4x32 with 6" Eye Relief?0 -
I guess I'll answer your question with a question: Does the 3-9x really have a wider field of view than the 1.75-4x and still have 6" of eye relief, or is it what's called "puffing", like in other forms of advertising? As an example, I have a Bushnell Elite 3200 2-6x32mm handgun scope, which is supposed to have a consant 20" of eye relief throughout its entire magnification range. On one handgun I have where the Bushnell is mounted on the barrel shroud, it works fine for me from 2x to 4x. At 5x it starts to black out. At 6x it blacks out completely. I don't think I'd call that "constant eye relief" throughout its magnification range.
Even at that, the Bushnell has 4" to 6" more eye relief than a Burris 1.5-4x handgun scope I have mounted on another handgun where the rear sight was. The Burris is supposed to have 14" to 18" of eye relief, but starts to black out even at 1.5x. The Burris does have a much wider field of view, but the eye relief makes it almost unuseable.
What I would suggest is to go to a stocking dealer, and try out the scopes you're interested in, and not just rely on the advertised specifications. They're not always the same. IMHO.0 -
You make a good point, Raoul, and I appreciate you responding. Bushnell's website makes a big point over the "Extended Extra Eye Relief" for both the Banner 1.75-4x32 and the new Banner 3-9x40. It also does show the 3-9x40 as having a wider F.O.V. Could this be "puffing?" Perhaps. If so then it would be false advertising on Bushnell's part, and I wouldn't want to give them my business anyway. But I guess it could also be a typo in Bushnell's information (I noticed some others on the website too ). That's why I am trying to get more information.
You're right about getting a first-hand look at it. I have been trying to get ahold of one, but nobody seems to have them except by order (not even Bass Pro had it).0 -
Bushnell specs on the Model 71-1426 1.75-4X32 IS correct, and w/out any misrepresentation.
This scope was designed for Intermediate Range (IR) style firearms, and is a smart setup.
The laws of Physics are the same for all makers, and I'll help clarify what you're reading, and may be seeing.
Please note on the scope specs two main things that are different, and will affect the end results:
1. Objective size 32mm vs 40mm.
2. Over All Length. 10.8" vs 12.0
Take #1 first; Amount/size of entering light vs Exit Pupils.
At 3X for each scope Exit Pupil for each WILL be;
1.75-4X32 is 10.6 mm.
3-9 X 40 is 13.0 mm.
Because there is a larger amount of light AVAILABLE the internal lenses maybe(note...maybe) designed to focus at longer distances INSIDE, and out of of the scope.
But this requires.....some changes, one which leads us to #2.
#2. In order to give a longer Eye Relief (6")on this new type Intermediate Eye Relief LONG GUN scope (for Scout/Shotgun/Muzzle Loader), at higher magnification the OAL must be longer for a clear edge to edge FOV, and a good quality sight picture.
Since the light waves have to be bent to be focused, a longer tube (sometimes the eye piece also is done) allows for a more correct and precise positioning of the internal lens assembly in to provide a quality sight, a longer eye relief, AND a larger FOV.
A couple 'optical rules of thumb.
To keep an optically correct, and resolute (sharp) picture:
1. As power(magnification) is increased the FOV will be reduced. Vice versa for decreasing power.
2. Focal Point(s) which can also be described as Eye Relief points are the exact distance(s) you will see a correctly focused picture behind the occular eyepiece and will NOT vary with magnigfication changes if the optics are made right, AND adjusted correctly by the user.
True eye relief measurement is done from the lens to the eye, not the scope end.
3. Focal points may be set at different distances to meet the application. Ie, Rifle scope vs Intermediate Range (shotgun/muzzle loader/scout style) vs Handgun all have different Focal Points or Eye Relief spots.
4. Objective size will affect the Exit Pupil, which can affect the FOV. So....generally larger Objectives can mean an increase of FOV. Not always. A major influence of FOV is in the Occular Eye Piece. They can look the same, but internals will be different.
FOV for both scopes @ 3X WILL be:
1.75-4X32 about 26 feet.
3-9X40 about 40 feet.
Remember if measuring the 6" Eye Relief(Intermediate Eye Relief) that's desighed to be mounted ahead of the receiver against a 3"-4" tya's designed for a receiver mount.....things must change.
PS: Note a few spelling errors. Those are my "Bushies" in honor of "W". President George Bush.
There may be a few slips of the tongue-finger here and there, but the heart of the content is true and correct.
Happy Bullet Holes!0 -
call the contact at the mfg during the week and let their expert help you - it is worth the call 0
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