Binocular "Dioptre adjustment"?

[jimmy the one]

I have three decent pairs of binoculars, why is it they only have a dioptre adjustment on ONE eye only?, surely if my eyesight is nonstandard it would affect BOTH eyes equally. P.S. There is no specific category for "bins", cameras are the closest subject!!
koops91, be a good boy and GO AWAY, YOU NUTTER. what on earth has your rantings got to do with my question.

[Michael Steen]

This is because you can adjust the focus for the left eye with the main focus.
What I usually do is cover my right eye and get the best focus I can by using the central focusing bar/wheel. Then I cover my left eye and fine-tune the adjustment using the diopter for the right eye.
Voila! Perfect adjustment!

[Carlos_dfc]

The dioptre adjustment on binoculars is simply there to take up the difference between one eye and the other.

Cap the side with the dioptre adjutment, and focus while looking through the other side - then change the cap to the other side, and focus the dioptre side USING THE DIOPTRE ADJUSTER ONLY.

This will equalise both sides of the bins to match any difference between your eyes..


For example - I know that my own spectacle 'prescription' is +0.25 for my right eye, and +0.75 for my left eye.
A difference of 0.5 dioptre
By setting a pair of binocs to +0.5 for my left eye (or -0.5 if the adjuster is on the right eye), I know that they will be OK for my own personal use.


edit
LOL - beat me to it Michael