OK, I can mostly agree with this and is the sort of answer I was driving toward getting with regard to my last post.
However, once the elements from the first quoted paragraph are specified, it is still a Scmidt-Pechan, an Abbe Koening, or a porro. So is specifying the elements actually design, or is it just specifying the elements in the established design? Seems there is (or at least could be) a difference to me. If specifying the elements is the generally accepted criteria for design, that is more than OK with me.
I agree that my dream house may well seem ill specified to some and it got botched with poor design and QC. An analogy is never perfect.
The prism type...and coatings... are part of the design, just like the lenses.
There isn't actually an established design for this prism and that power
and objective. There aren't fixed sets of 'accepted criteria' because
there are tradeoffs and customer preferences vary.
The design of the eyepiece and/or flattener/focuser lens
is of greater importance than the prisms, usually. That controls the field
properties. And the mechanical smoothness and precision are connected
tightly to keeping left-right sharpness, and thus 3D and contrast
improvement in the cortex. The design is practically everything need to
do the whole optical job. Even the baffling and blackening along the
path is important. You can see examples in the 70s-80s of the exact same
collection of lenses and prisms with either stainless precision focusers
and lamp-black tunnels or short tunnels, wobbly plastic focuser arms,
and semi-gloss interiors instead of flat black. Just those things make
for a hazier, less vivid view with poor 3D. The design is anything that counts.
You could decorate the outside weirdly or in camo, but the optical path
is what matters.
