Pentax K-7 Operating Manual page 57

Adjust the viewfinder to suit your eyesight.
If it is difficult to see the viewfinder image clearly, slide the diopter
adjustment lever sideways.
You can adjust the diopter from approximately-2.5 to +1.5 m-1.
I
Look through the viewfinder and
slide the diopter adjustment lever
left or right.
Adjust the lever until the AF frame in the
viewfinder appears sharply focused.
Point the camera at a white wall or other
bright and consistent surface.
AF frame
• The Eyecup FR is attached to the viewfinder portion when the camera leaves
the factory. Diopter adjustment is available with the Eyecup FR attached.
However. adjustment is easier with the eyecup removed
• To remove the Eyecup FR, press n one
side and pull it out in the direction of the
arrow.
-o attach the Eyecup FR, align it with the
groove on the viewfinder eyepiece and
push it into position.
• If it is difficult to see the viewfinder image
clearly even if you set the diopter
adjustment lever, use an cptionai diopter
correction lens adapter M. However. the
Eyecup FR must be removed to use this
adapter. (p.302)