Diopter compensation

In optical devices, diopter compensation describes the possibility of compensating for ametropia in the eye when using eyepieces by correcting the refractive power .

description

The correction of the refractive power is usually achieved by mechanically adjusting the image sharpness on the eyepiece.

The strength of the correction, like the refractive power, is usually given in the unit of measurement diopters and is usually between −3 and +3 diopters. A diopter compensation of zero means that a human eye with normal refractive power will see a sharp image. Positive diopter numbers increase the refractive power for the farsighted , and negative diopter numbers decrease the refractive power for the nearsighted .

Applications

Binoculars

Ring with scale for setting the diopter compensation on the left eyepiece of a binocular

A typical problem arises with binoculars , such as binoculars or stereoscopes , when the two eyes have different refractive powers. Here an eyepiece is often provided with a diopter compensation so that the difference for the corresponding blurred eye can be compensated for if the other eye has been focused .

Monocular

Wheel for setting the diopter compensation to the left of the eyepiece of a system camera

Eyepieces with diopter compensation are also used with some monoculars , for example with higher quality viewfinder cameras , if the optical imaging of the lens cannot be adjusted for the observing eye, but for a photographic film or an image sensor . With SLR cameras , the photographer looks through the eyepiece, for example via a pentaprism, at a permanently installed focusing screen . Depending on the refractive power of the eye, the diopter compensation can be used to focus the viewfinder image for the respective photographer on the eyepiece without having to adjust the lens or the focusing screen.

In devices with an electronic viewfinder , such as mirrorless system cameras , the image of the lens is not imaged through an optical beam path in the viewfinder, but only comes indirectly from a small electronic screen . In this case, the viewfinder image can be focused, for example, by varying the distance between the screen and the eyepiece.

Additional advantages

By using the diopter compensation, it is also possible for many people who wear glasses to use an eyepiece without glasses and without any loss of image sharpness or the visible angle of view .

With optical devices with a high-resolution electronic viewfinder , the many advantages of live view or, for example, operating settings can also be achieved without glasses using the viewfinder.

Web links

• What does: Diopter adjustment , Stiftung Warentest (test, June 2008)

Individual evidence

1. ↑ Eyepiece - diopter adjustment , microscopy, basics, University of Vienna (online)
2. ↑ Technical information on monoculars - diopter compensation , monoculars, www.monocular.info (online)
3. ↑ Diopter adjustment ( Memento of the original from April 21, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Intercon Spacetec (online) 
4. ↑ The diopter adjustment for binoculars (PDF; 1.4 MB), MINOX, interesting facts about binoculars, guide, page 23 (online)
5. ↑ Photo tip: Diopter adjustment , www.prophoto-online.de (November 10, 2006, online)
6. ↑ What means: diopter adjustment , Stiftung Warentest (test, June 2008)