reason behind lower cost of porro prisms?

As I understand it, good roof prisms are more expensive to make than porro prisms, and if phase coating is added to the roof prisms (which is unnecessary in porro prisms), that drives the cost up even more.

Still, the gap between the cost of good porro prism binoculars and good roof prism binoculars seems huge. With the possible exception of Steiner, I can't think of any porro binos that are anywhere near the cost of higher end roof binos. Is this because good roof binos are really that much more expensive to make, or is it because their isn't the same demand for high-end porro binos?

Hi

It is more than just the optics. It is also a matter of securing the prism, since prism alignment is far more crtitical in a roof prism. Cheap porro prisms are just cemented in place and even better prros sometimes just use clips. A roof prism, though, requires a sohisticated cage addembly to secure it and adjust it. That leads to different body construction and focusing systems as well. The end result, though, for a roof is internal focusing, more durability. smoother focusing and, generally, a longer lifespan. It is those features, much more than the pahse-correction, that lead to the greater expense.