Hunting Washington Forum

Equipment & Gear => Scopes and Optics => Topic started by: Gobble Gobble on July 22, 2015, 07:22:56 PM

Title: Help me under stand Bino FOV
Post by: Gobble Gobble on July 22, 2015, 07:22:56 PM: I'm in the market for a new set of binos. Please help me understand the Field of View. Both linear and degree. Using an old set of binos as an example they are 7x35 (power/magnification x objective lens in mm) got it, 420 yds. @ 1,000 yds. (not quite understanding this) and 8 degree FOV (how is this calculated). Is the 420 yds. @ 1,000 yds. the distance away the object appears with the 7x magnification or is it @ 1,000 yds. I can see a left/right linear distance of 420 yds.? I know with a higher magnification the X yds. @ 1,000 yds. decreases which leads me to believe it's LFOV . I want a bino with a wide FOV, looking at 8x or 8.5x range, with a 42mm or 50mm objective. If my math is correct the 8x42=5.2mm exit pupil and the 8.5x50=5.9mm which is good for low light use but that is another topic altogether.

So ? 1) 420 yds. @ 1000 yds. is the distance object an appears with said 7x magnification or is it linear FOV left/right @ 1000 yds.?
? 2) How is the degree FOV calculated?

Thanks for helping :tup:
Title: Re: Help me under stand Bino FOV
Post by: elkaholic123 on July 22, 2015, 07:53:32 PM: Try this
Title: Re: Help me under stand Bino FOV
Post by: elkaholic123 on July 22, 2015, 07:56:16 PM: Add
Title: Re: Help me under stand Bino FOV
Post by: Gobble Gobble on July 22, 2015, 08:11:34 PM: Thanks. Thus the reason they make you take calculus before trig. :bash:

At say 1,000 yds with naked eye is there a formula to know what distance an object appears to be at with say 8x, 8.5x, and 10x?
Title: Re: Help me under stand Bino FOV
Post by: bobcat on July 22, 2015, 08:15:07 PM: With a 10x bino, something at 1000 yards would look like 100 yards. Just divide the distance (1000 yards) by the power of the binocular (10).

For the field of view, in your example, it would be 420 FEET, not yards. And that's the width of the area you're seeing at 1000 yards.
Title: Re: Help me under stand Bino FOV
Post by: Gobble Gobble on July 22, 2015, 08:24:46 PM: That simple math I can do its the trig required to calculate the linear and angular FOV that is a challenge.
Title: Re: Help me under stand Bino FOV
Post by: bobcat on July 22, 2015, 08:28:30 PM: I've never had a need to calculate any of that stuff. Just look at the field of view numbers for 1000 yards that are given for all binoculars.
Title: Re: Help me under stand Bino FOV
Post by: Gobble Gobble on July 23, 2015, 08:05:14 AM: What it you don't have the binos to look at... then what? I like math.
Title: Re: Help me under stand Bino FOV
Post by: thinkingman on July 23, 2015, 10:02:03 AM: Quote from: bobcat on July 22, 2015, 08:15:07 PM
With a 10x bino, something at 1000 yards would look like 100 yards. Just divide the distance (1000 yards) by the power of the binocular (10).

For the field of view, in your example, it would be 420 FEET, not yards. And that's the width of the area you're seeing at 1000 yards.
Yes.
420 YARDS would be like more than 180 degree vision.
OP, congrats on focusing(baddumPah!) on a truly important feature of optics.
Once you've had a really wide FOV, you can't go back.
That's why it's so hard for me to consider anything but my Nikon Premier LX 8x32...7.8 degree angular FOV.
409' @1K.
Like a picture window.
Title: Re: Help me under stand Bino FOV
Post by: Fl0und3rz on July 23, 2015, 10:15:58 AM: Probably more than you ever want to know about hunting/shooting optics.

http://www.swarovskioptik.com/hunting/blog/ontarget_01

Filed of view discussed in part two.

This covers conversion between angular and linear as a rough approximation.

http://www.eagleoptics.com/articles/technical-guide/field-of-view

1) linear FOV left/right @ 1000 yds. This is a 7x, because the binos are not variable.
2) How is the degree FOV calculated? Linear(ft.) /52.5 = Angular(degrees)
Title: Re: Help me under stand Bino FOV
Post by: Jonathan_S on July 23, 2015, 10:24:45 AM: Quote from: Gobble Gobble on July 23, 2015, 08:05:14 AM
I like math.

Prayers sent
Title: Re: Help me under stand Bino FOV
Post by: Fl0und3rz on July 23, 2015, 10:29:50 AM: Quote from: Jonathan_S on July 23, 2015, 10:24:45 AM
Quote from: Gobble Gobble on July 23, 2015, 08:05:14 AM
I like math.

Prayers sent

:chuckle:
Title: Re: Help me under stand Bino FOV
Post by: Bob33 on July 23, 2015, 10:39:14 AM: Quote from: Fl0und3rz on July 23, 2015, 10:29:50 AM
Quote from: Jonathan_S on July 23, 2015, 10:24:45 AM
Quote from: Gobble Gobble on July 23, 2015, 08:05:14 AM
I like math.

Prayers sent

:chuckle:
Just remember...
Title: Re: Help me under stand Bino FOV
Post by: Fl0und3rz on July 23, 2015, 10:39:52 AM: pi are not square. pi are round.
Title: Re: Help me under stand Bino FOV
Post by: CAMPMEAT on July 23, 2015, 10:59:14 AM: C'mon guys. I only graduated from high school and skipped all math classes............................ :tup:
Title: Re: Help me under stand Bino FOV
Post by: Curly on July 23, 2015, 11:15:44 AM: Quote from: Fl0und3rz on July 23, 2015, 10:39:52 AM
pi are not square. pi are round.

I don't know.......that pi does appear to be square. Didn't even notice the pi symbol in the crust at first. :chuckle: (Now I'm craving apple pie). :EAT: