6-7x vs 8x Magnification (1 Viewer)

[mwhogue]

Perception is reality? The image on the left is from a binocular with a 7-degree field of view. The image on the right shows that object—at the same magnification—but with a 9-degree field. Quite often, the observer sees a larger field of view and equates it to more magnification. The difference, in better binoculars, lies in the unsung field stop. :cat:

Just a thought,

Bill

Bill,

Thanks. Your point about a larger FOV affecting the perceived magnification probably explains why the magnification of the 6.5x32 Kowa (actually 6x as measured by GJS) with its 525' FOV *appears* to me to be larger than 6x or even 6.5X and closer to 7x.

Mike

 

[Troubador]

Why 8x is popular

There are certain birds, with certain features you want to see, in certain circumstances, in certain lights and at certain distances when:

The naked eye is enough and you see the features as the bird flies close to you.

6-7x is enough because you got a good view at not too great a distance and you were looking for a moderately visible feature like a wing bar or eye stripe or shape of the bill.

8x is enough despite the bird being somewhat further away

10x is enough despite etc etc

Until even a scope with 100x isn't usable because of the distance or atmospheric disturbances.

But binos aren't only characterised by magnification. As you increase mag you normally find the field of view reduces and larger fields of view help locate birds in a variety of circumstances.

It just so happens that for many people increasing the magnification to 8x but for general purposes not going for a higher magnification is a good balance between mag and fov.

So of course lower magnifications are perfect in certain circumstances and in others 10x or higher is desirable. Not everyone wants or is fortunate to be able to afford multiple binoculars to use in different circumstances so 8x is often chosen as a good balance although in some countries and habitats 10x is the most popular.

Lee

 

[jring]

Granted we (luckily) don't have to read serial numbers on a bird...

Hi,

so those numbers on the plastic rings around the leg are not serial numbers?

Puzzled,

Joachim, who is fine with either 7 or 8x, 10x only when I'm quite sure that I will only watch stuff at high distances

 

[Pinewood]

Hello Lee,

Very well put but there is another limiting factor, handshake, which varies among users and in use. I can hold an 8x very well for targets at the horizon or fairly close to the horizon. At 10x, I have difficulties for a prolonged observation. For bird watching, I am fine with an 8x, most of the time. For astronomy, 7x works for me, even near the zenith. There is good reason that stabilised binocular are available in 8x.

Stay safe,
Arthur :hi:

 

[Troubador]

Hello Lee,

Very well put but there is another limiting factor, handshake, which varies among users and in use. I can hold an 8x very well for targets at the horizon or fairly close to the horizon. At 10x, I have difficulties for a prolonged observation. For bird watching, I am fine with an 8x, most of the time. For astronomy, 7x works for me, even near the zenith. There is good reason that stabilised binocular are available in 8x.

Stay safe,
Arthur :hi:

You are absolutely right Arthur. Handshake is another important factor.

Lee

 

[Chosun Juan]

Lately I have been using my kowa bd II 6.5x32 quite a bit and enjoying its easy eye placement with 5mm exit pupil, great depth of field, bright view and wide field, etc. When ever I compare it to an 8x32, I struggle to see any benefit from the extra magnification ie. I don't find I am able to see that much more detail. Of course, these are only hand held comparisons and not mounted on a tri-pod. A good example was just yesterday when I observed a merlin perched high up on a tree from approximately 150 feet away. If I compare to a 12x binocular then I am able to see more detail, although it becomes more challenging hand holding a 12.

I'm just wondering if anyone else has compared a 6-7x binocular against an 8 and feel the same way? If so, my next question is why do so many people gravitate to an 8 power binocular? Is it simply because there is so much selection out there in this power in the marketplace?

Fotbg -

I started using some 7x porros (which admittedly weren't that great). One of the stated benefits of lower magnifications (their greater depth of field) , I found a bit annoying. I actually wanted less dof for the viewing I was doing so I could lock onto a definite focus. I also wanted a bigger image size.

It just so happens that the 8x roof I have now is steadier to hold, has a larger Fov, a faster focus (which importantly goes the right way - CW to infinity), and lesser dof giving a definite focus point than those 7x.

I actually would appreciate a larger image size still, and have tried various other magnification - 8.5x, 10x, 12x, 15x. These involved various compromises that I ended up not wanting to live with. Dof starts getting real thin at 10x and above, and so does Fov - necessitating the highest quality bins.

The features I value in a bin are:-
* Light weight
* Great ergonomics for a steady hold
* Sharpness - nearly to the edge or more is better
* Great CA handling
* Great glare handling
* Bright, neutral colour rendition
* Sufficient ER ~18mm for my glasses which correct short sightedness
* Fast, Precise, CW to infinity focus
* An Exit Pupil of 5.25mm + ideally
* Decent Fov of 140m@1000m, or an AFov of 70° +

Some of those such as the ER/EP <-> Fov <-> Weight, equation becomes difficult to achieve.

Ideally, I would like over 140m with an 8x. 148m well controlled like with the 42mm SF is good.
Ideally something like 8.5x or 9x 45 with Fov of 150m - 148m and weighing <650grams would be awesome - but that's a unicorn, and nobody does one of those yet ..... :cat:

So at the moment 8x it is .....







Chosun :gh: