Hi!
MZ-5 has classic interface and viewscreen with a little larger
maginification than other two cameras... It is 0.8 against 0.7. But I
may be mistaken.
Formally, MZ-5 is considered to be one/half class higher than MZ-30 or
MZ-7. Also, MZ-30 has a crippled mount so should be considered big
no-no.
Indeed, you can point your browser to kmp.bdimitrov.de - the Pentax
"Bible" and see for yourself <g>...
I have MZ-6 but shoot mostly with ME Super...
HTH.
Boris