Some SLRs come with built-in dioptric adjustment in their viewfinders, e.g. -2.5 to +0.5 diopter. I first thought they are used to help people with myopia or astigmatism (I have both) to focus without their eyeglasses, but of course it was not meant to be used like that.
Can anyone kindly explain what is dioptric adjustment and what is it used for? Thanks!
Can anyone kindly explain what is dioptric adjustment and what is it used for? Thanks!