What determines Field of View? (1 Viewer)

[John S.]

The Celestron Ultima DX 8x32, perhaps with a 8.2° FOV. I have a pair. Sharp with some field curvature. Oversized prisms (the design looks like it was meant to have other objective sizes like the SE). Heavy at 1kg. A rather good bird feeder bin.

Actually the original Vixen/Unitron/Celestron 8x32 Ultima binoculars precede the DX series by about 10 years and were made in Japan. They were widely sold in the late 1990's and early 2000's under those three brands at least and possibly more. They have an 8 degree field of view, are multicoated and use BAK4 prism glass. If anything they are quite compact and reasonably light with a good close focus.

 

[Kevin Purcell]

Actually the original Vixen/Unitron/Celestron 8x32 Ultima binoculars precede the DX series by about 10 years and were made in Japan. They were widely sold in the late 1990's and early 2000's under those three brands at least and possibly more. They have an 8 degree field of view, are multicoated and use BAK4 prism glass. If anything they are quite compact and reasonably light with a good close focus.

Thanks for the clarification, John.

Do you have (or know of) any photos? Web searches are bringing up too many recent similarly named bins.

 

[John S.]

Thanks for the clarification, John.

Do you have (or know of) any photos? Web searches are bringing up too many recent similarly named bins.

Here's one in Spanish

http://www.optical-systems.com/vixen-ultima-8x32-prismaticos-p-271.html?language=es&currency=EUR

The original Vixen Ultima series is traditional Zeiss style compact bin with a really comfortable focusing wheel. Vixen made several interesting glasses in that series including 8x56, 9x63, 9.5x44ED, 6.5x44ED, 10x50 and a few others that escape me. I tried the 9x63 and found them to be way too big for the view delivered. Eagle Optics closed out their branded version of the Celestron 9.5x44 ED glasses which I picked up several years ago. Those are knockouts for nighttime observing and do quite well during the day.

 

[birdazzLED]

If you can believe this...why am I sharing this? oh yeah, FOV - I have a Canon 5x17 FC roof prism with 9 degrees and 16mm EF. 5' CF. It has an Aspherical Super Spectra Multi-coated lenses that are surprisingly sharp with good contrast - from edge to edge. It's actually brighter than my Zen Ray 8x43 during the day but I guess that's because of the low power. The strange thing is that there is no diopter adjustment but my eyes don't seem to need it and i'm not sure why because other bins I do.

Here's a 7x35 18-Degree! amazing! must be a record of some sort - or a 65x42 WA II 18-Degree Field!

 

[henry link]

Here's a 7x35 18-Degree! amazing! must be a record of some sort - or a 65x42 WA II 18-Degree Field!

I wouldn't place any trust in those numbers. 10m/10000m would be 3ft/1000yards, which certainly would be a record of some sort. ;-)

 

[John S.]

If you can believe this...why am I sharing this? oh yeah, FOV - I have a Canon 5x17 FC roof prism with 9 degrees and 16mm EF. 5' CF. It has an Aspherical Super Spectra Multi-coated lenses that are surprisingly sharp with good contrast - from edge to edge. It's actually brighter than my Zen Ray 8x43 during the day but I guess that's because of the low power. The strange thing is that there is no diopter adjustment but my eyes don't seem to need it and i'm not sure why because other bins I do.

Here's a 7x35 18-Degree! amazing! must be a record of some sort - or a 65x42 WA II 18-Degree Field!

I like the smaller bins too. your Canon sounds like an interesting binocular. I've got a Nikon 5x15 Titanium roof prism model with a 9 degree field and a close focus of 1.2m. Great for butterflies and it too delivers bright and sharp images.

I'm waiting for someone to jump on that 18 degree (126 AFOV) bin and give it a field test. As with the inexpensive low power Bushnell Ultrawides the image may suffer because the fov was pushed too far.

 

[birdazzLED]

I find it impossible to believe a 65x42 would have an 18-Degree Field. The problem with the Canon is the ER is so great that I have to hold the bin away from my eyes when not using glasses. I just use my finger between my nose and bin. I'm thinking they were designed for people that wear glasses so there is no diopter adjustment.

 

[henry link]

There's no mystery about these unbelievable FOV numbers. They're fictitious, concocted by somebody who didn't know enough to realize that they don't make sense.

A 9 degree true FOV in a 5x binocular is no problem. The apparent FOV is only 45 degrees, pretty narrow and easy to do with a simple eyepiece. An 18 degree FOV in a 65x binocular would have an apparent FOV of almost 1200 degrees. Your head would have to spin around three times to see that.

 

[John S.]

I find it impossible to believe a 65x42 would have an 18-Degree Field. The problem with the Canon is the ER is so great that I have to hold the bin away from my eyes when not using glasses. I just use my finger between my nose and bin. I'm thinking they were designed for people that wear glasses so there is no diopter adjustment.

I hadn't focused on that binocular. The numbers as printed make no sense at all. A 65x42 bin has a pinpoint for an exit pupil. The objectives look about right size, but nothing else is right with that advertisement.

However, check the identically named 65x42 "Mystery" binoculars below that are claimed to have 12x magnification with a 32mm objective and a 2.6 pupil (exit?). Now I'm thinking that 65x42 is a poorly or deceptively chosen model name.

http://mystery.en.alibaba.com/product/243609820-200533258/Mystery_65x42_Binoculars_Telescope_12_Magnification.html