That was during the Great Reign of the Porro when roofs were inferior because of their out of phase prisms, slightly fuzzy images, and dimmer views.
The story goes, someone posted this anecdote, that it was the ladies of the birding clubs with whom roofs caught on, with their dainty, upper crust in-breed hands (sometimes webbed so they couldn't spread their fingers wide enough to wrap around a porro
I can see the advantages of roofs, the more robust build quality (or at least potentially if made right), the superior WP with internal focus (though that also brings with it liabilities as both Henry and Holger have pointed out), closer focus, smoother focus in the winter than external focusers, and more compact design (though not necessarily an advantage for the Big Handed Birder with non-webbed fingers).
But the fact that most porros are relegated to the low end today while birders have to pay through the proboscis to get the same quality as a premium porro tells the story of how their respective evolutions diverged.
It's been a "punctuated equilibrium" for roofs, because the whole Roof Revolution started only a little over two decades ago with the Zeiss 7x42 B/GA and Leica Trinovids. Although Swarovski had been offering its SLCs, they were the darlings of hunters, not birders. Swaro didn't jump on board the Peace Train until the EL.
Nikon burst on the scene with its LX/HG and gave the Top Three a run for the money. Meanwhile, manufacturing moved to China and the Pacific Rim, and a plethora of Chinbin companies arose with more models than you can shake a stick at.
Technology such a phase-coatings, prism coatings - aluminum, silver and dielectric, twist-up eyecups, internal focus, on-the-focus-rod diopters, etc., etc. trickled down to mid-priced and even entry priced levels.
Then the "clone" was born, where different companies re-badged basically the same bin in new "clothing". They started turning them out in the Chinese factories like Chevys during GM's heyday.
Funny though, how Zeiss and Leica still don't make their top bins with high ER like Nikon and Swaro and even some mid-tier roofs.
If I had the gumption, youth and wherewithal to start a company, I'd revive the porro and advance the model. While the dog legged prisms will always make the German-style porro less robust than a roof, an internal focuser done right (i.e., one that doesn't add CA or cause each side to focus differently), perhaps using Porro II prisms to keep the design slim for birders from the Daughters of the American (Roof) Revolution.
It would still be a hard sell due to the saturated roof prism market, but if even Dennis can be turned around, there's hope for other birders to rediscover the benefits of the porro design if porros were designed with birders and hunters in mind. I think hunters in particular would find porro's better depth perception and 3-D effect very helpful in separating prey from background if the porro could be designed tough enough to withstand "the mud, the blood and the beer." As we've seen from the truck tire runover with Steiner porros, it can be down with IF EP porros, and it should be possible with internal focus porros as well.
But alas, I have not the gumption, youth nor wherewithal to initiate the porro rival so the roof revolution will continue until the digi-bin revolution takes over.
Ignazio
