Eyepiece Correction Lens for Dynax 4



Can anyone help me to select the correct eyepiece correction lens for my Dynax 4? As I understand it the viewfinder is set at -1 diopter, and I cannot quite focus on the apterure/focus/shutter speed info, being slightly shortsighted. Now, if I added a -1 diopter correction lens, would this adjust the viewfinder to -2 diopters, which I would hopefully be able to focus on, or do I need to buy a -2 diopter correction lens to get this setting?