Re: [Paddlewise] binocs vs monocular

On 24 Mar 2005 at 8:00, Keith Wrage wrote:

> Here are 3 diverse choices:
> http://www.kayakacademy.com/catalog/BMonoc.html (6x30 monocular with
> neoprene float, $135)
> 
> http://www.binoculars.com/products_v7/Bushnell_8x25_H2O_FRP_Compact_56
> 40.html (compact 8x25 cheapie binocs, $40)
> 
> http://www.binoculars.com/products_v7/Nikon_8x25_Mountaineer_II_ATB_16
> 5.html (compact 8x25 quality binocs, $185)
> 
> Recognizing that price dictates quality in some regards - how bad
> would the $40 pair be?)  Disposable?

While these will in no way compare to the high-end binocs, they might 
be reasonable for someone that only wants occasional use with a price 
that won't hurt if they are lost or damaged.  I have a relatively 
cheap pair of Bushnells quite similar to these and they are 
surprisingly sharp and clear.

> The field of
> view for the above are (at 1,000 ft):  340, 370, 330 feet
> 
> So...can someone explain why the 6x30 would be better than the others
> in a moving craft?  It would seem that they all view the same amount
> of area - so it isn't as though one is incredibly more powerful than
> the others.

They show roughly the same field of view, but at different 
magnifications.  Comparing the monocular to the Nikon means that 
you'll see a smaller image (3/4 the size) of the same view with the 
monocular.  The widest field will seem more like you're there rather 
than looking at a little picture.

If you wear glasses, eye relief is important.  Eye relief is the 
distance between the eyepiece and the focal plane of the binoculars.  
If that distance is short, your glasses will prevent your eye from 
getting close enough to see the whole image.  If long enough, you 
will see the full image.  For that reason, it is important to try the 
binocs/monocs before you buy.

The exit pupil size of these will be different.  The 8x25 have an 
exit pupil of 3mm (25 divided by 8) and the monocular has an exit 
pupil of 5mm (30 divided by 6).  That means that the monocular will 
be easier to see thru most of the time - you are peeking thru a 
bigger hole.  This can be a factor in usability.

Mike
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