Got a list of FOV by model? & Actual minimum IPD? & close focus distance? (1 Viewer)

[Charlie Yardbird]

I'll start.
For min IPD, I measure from one inner edge to the other, trying to look straight down
with one eye to line it up, then straight down on the other side. Not sure how much
individual variation there is on the hinges touching. No need to try to visualize the
innermost "ring" because they are all the same thickness, so whatever ring is easy
to see.

Audobon Mark II (Type 2b) 8.5x44, 445 ft Extra Wide Field so 8.49 deg, min IPD ~53mm
Holiday Mark II 7x35, 578 ft Extra Wide Field so 11.03 deg, min IPD ~54mm

Commodore 7x50, FOV unstated, min IPD ~56mm
Triton 7x35, 367 ft so 7.00 deg, min IPD ~48mm
Oceanic 6x30, 593 ft so 11.32 deg, min IPD ~49-50mm

 

[Binastro]

HR/5 8.5x44 8.26 degrees measured.

The 445ft version from memory is 8.35 degrees measured by star separations.

I suppose the list is meant for Swift binoculars but,

Minolta Standard MK 7x35 11.05 degrees measured.
8x40 version 9.4 degrees measured.
10x50 version 7.65 easy field, up to quoted 7.8 degrees with difficulty.
Canon 18x50 IS 3.85 degrees.
Zeiss 10x42 HD Conquest 6.65 degrees.
Komz 12x45 5.4 degrees.
VisionKing 5x25 14.8 to 15.4 degrees measured 15.8 degrees claimed.
Foton 5x25 12.2 degrees.
Amplivid 6x24 12.2 degrees.
Komz 6x24 12.2 degrees.
Dowling and Rowe/Libra 4x22 16.5 degrees.
Bushnell Xtrawide 4x21 18.5 degrees.

All by star measures.

The stated fields and magnifications on binoculars are often wrong, although some makers are accurate in what they quote, although their websites may be wrong.

Regards,
B.

 

[elkcub]

I was about to use this on a different thread, but I'll post it here too. The chart comes from Dr. Henry Paul's 1964 book "Binoculars and All-Purpose Telescopes", Pg. 68. This should provide historical perspective. Make sure to read the asterisk notes at the bottom for definitions.

Ed

 

[Charlie Yardbird]

Very nice. Anyone have an app that can rescan it & turn it into actual text that can be put into a spreadsheet?

 

[Binastro]

The problem with manufacturers specifications is that they are often not true.

Forget the scams like 60x60 binoculars that are 8x21.

Bushnell in particular overstate magnifications on some models.
The 4x21 is 3.5x21 or 3.4x21 according to another contributor here.
5x25 is about 4.4x.
They do this to overstate AFOV.

A Celestron 8x30 was about 6.7x27.

There are numerous 50mm binoculars that are around 46mm.

60mm ones that are around 52mm.

15x70 about 15x63.

Optolyth 12x50 about 12x42.

As to field sizes the only way is to actually measure them.
But great care has to be taken, as hand held fields are wider than tripod mounted fields because of hand movement and image memory.
If the binocular is slightly out of alignment or the IPD not really accurate fields are wrong.

At best measured field sizes are in my experience accurate to 2%.
If measured casually, maybe 10%.

AFOV is very difficult to judge by eye and needs to be measured.

Regards,
B.

 

[Binastro]

The Leitz Trinovid 10x40 had different versions with different field sizes.

B.