I really need some help...please

[woollyback]

Hi folks,

I am more bird photography than watcher although recently I have been looking for a pair of bins that would do watching as well as general purpose walking around.

I am trying to understand binocular nomenclature and what I need from a pair as there is so much info I just want to try and simplify it for me.

So lets take make A X by Y

X relates to magnification ie in photography terms a 10 times A would equate to image seen by 500mm lens

Y relates to objective diameter and thus feild of view.

Is this correct or am I missing something and have got wrong end of stick.

Thanks for any info to help.

Cheers

Rob

[ThoLa]

X relates to magnification ie in photography terms a 10 times A would equate to image seen by 500mm lens

Y relates to objective diameter and thus feild of view.

Is this correct or am I missing something and have got wrong end of stick.

Rob


X relates to magnification ie in photography terms a 10 times A would equate to image seen by 500mm lens.

CORRECT.



Y relates to objective diameter


CORRECT.


and thus feild of view.

NO.

Y gives the light-gathering power, i.e. it is similar to 5.6/500 or 8/800.


The field of view is more complicated and cannot be infered from the magnification. There is no easy correlation of magnification and the aperture angle as in photography.

I am afraid the fov must be looked up fo each individual model under consideration. But even top brands are sometimes quite "generous" with respect to the numbers they publish. It is more like a "rule of thumb" indication of what might expect to see.

Maybe this helps a litte.
Tom

[Tero]

In addition to those factors, the eye pieces and eye cups vary a lot in binoculars. The way you hold your eye to a SLR camera is pretty much all the same in all models. The number we use here is eye relief. It has to do with the useability wearing glasses and also how much time you need to get the binoculars set to view something.
see
http://www.astronomics.com/main/definition.asp/catalog_name/Astronomics/category_name/tsb8e1qgp29729n75kc/Page/1