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Field of view in SCOPES
adisonrain
Member Posts: 35 ✭✭
OK, maybe from the getgo back in the early 80's I was spoiled with Redfeild wide angle scopes. My best friends Dad (the man who taught me how to hunt) had a 2-7 Redfeild Low Profile scope. The field of view and clarity were awesome. So, in the past year I have been on a search for a similar scope with the same features. Let me tell you it amazes me when there is so little to choose from in todays market and frankly, I don't get it. I thought I was really moving up when I bought a Bushnell Elite 2-7x32. When I looked through it the first time it was like looking through a straw! It was a big dissapiontment to have such fine optics but no wide FOV. I promtly sent it back. Oh, the FOV on 2x at 100 yards was 43 ft. So I started looking and the 2 SCOPES I found out of every single manufacture was the Busnell Legend 2-7x32 (go figure) which had a FOV at 2x (100 yds) of 55 ft. and the Swift 2-7x40 was at 60 Ft. (2x @ 100 yds.) Thats it. No one even came close to that. I will go with Swift since it has a bigger objective and have read good things about them. I do have an older Bushnell Trophy 2-7x32 (made in japan) which is off the charts wide FOV so I don't get Busnell with there narrow FOV in the Elite, took the Trophy 2-7x32 off the market and used a wider FOV on the Legend series. So the question woud be , whats up with all of this? Why would anyone buy a 2x scope only to have a narrow FOV and why are the manufactures making them this way?
Comments
Google turns up a number of references, like the following one
quote:Field of View
In addition to magnification the field of view of an eyepiece is important. The field of view is a function of the optics of the eyepiece itself and its magnification which is a function of the telescope focal length. Typical eyepieces have field of view ranging from 40? to 65? or more. The intrinsic eyepiece FOV must then be divided by the magnification to get the effective field of view at the telescope. A 25 mm eyepiece on a 1 meter focal length telescope has a magnification of x40. This will yield a 1? field of view if the eyepiece has a 40? intrinsic field of view
Another one http://www.astrobuysell.com/paul/fov.htm
Optically there is a Magnification Ratio that can't be fudged. Most common are 3:1 (1.5-4X, 2-7X, 3-9X, 4-12X, 6-18X), and 4:1 (1.5-6, 2-8X, 3.5-10, 3-12X, 4-16X, 5-20). 3:1 are easy to do, 4:1 harder but optically accurate, then the 5:1& 6:1 are very, very hard and very expensive. Swarowski, and Schmidt & Bender are the ones
Widefield FOV was very good, but wasn't overly great.
Back then people 'complained' that is was almost as long as the 2-8.
Redfield smartly did get a patent, simply 'cutting off' the top & bottom of the occular lens it's perspective balance made it look great.
Tail Gunner is also on target. Most every 2-7X are shorter scopes, and usually limited to 32mm so FOV has to be limited. A few 35mm-38mm's exist....and you will pay more to see more....better.
Because our eye automatically searches for the center, and 99.9% of shooting occurs in that area, companies have been advertising 'oversized' FOV's. They're simply fudging, and when comparing USEABLE (sharp & clear) FOV from edge to edge you'll see the sight picture degrade. Diffrerence is easily seen using optical charts designed for that.
2-7 are opticaly that great. Check out 1.5-6 in regular scopes, and some 3-9 im Short Mag-Compact. the split the difference and offer more.
I had one of those Redfield Widefields. That thing looked great, it looked so wide, it reminded me of a tv set. I killed a lot of deer with that scope.
So it actually was no wider than a regular scope, they just cut off the top and bottom? Well, that was a pretty good trick, fooled me.