Here are some images of a simple adaptation I made to my dioptrx to fit my 45 degree prism.  Click on the link above to jump to the full post!

Table of Corrective Diopters available for pop up magnifiers in the TLR Waist Level Finder

Rolleiflex TLR  2.8FX   4.0 FW and 4.0 FT    (will also fit 2.8 GX, F, 3.5 F and other models with removable WLF)

Follow the bump to see the table.....

One of the reasons I initially started shooting with the Rolleiflex was for the wonderful viewfinders with are big and bright.....

Corrective diopters are available but I have astigmatism...    But there is a solution!  Click on the post to read how....