Pentax SMC 5.5 lupe

I just bought this lupe and did a quick view on my Kodak 5x7 and it really picks up the grain of the gg. Is this a bad lupe for this or is my gg too course?

I use this lupe to view medium fortmat and 4x5 films and is very sharp and clear. I'm interested in this as well as I never tried it for GG viewing because of the transparent skirt on it. Great lupe though.