Auxiliary lenses, Rolleflex

My father, Ira Harrison taught commer. & color at NY School of Photog in the '50s...(REAL studios and such then..) HAD to be his darkroom assist. from age 12 to 18...Left his equipment to me incl a set of SUN Aux Wide & Tele lenses... for his, now our, Rolleflex. Anyone know the exposure factor(s)??? Thanks, Bill

I have the Yashica branded aux. lenses and these are probably similar to the "Sun" lenses.

Yashica has the following recommendations:

WIDE ANGLE:
75% increase in view
Makes lens a 58mm
Values on the focusing scale are halved
Yashica recommended "best" apertures f5.6-f11

TELEPHOTO:
50% decrease in view
Makes lens a 113mm
Values on the focusing scale are doubled
Yashica recommended "best" apertures f5.6-f11

NB: no exposure correction needed for either lens

AUX ROLLE LENSES

Racer, Thanks for the help.....I'll post results, Bill

When I use my WA adapter the 'wide open' pictures give kind of a "HOLGA" look without the shortcomings of a plastic camera. When stopped down past f11 the image gets better at the edges but you get the characteristic Diane Arbus vignetting which does not bother me. Have fun.