henry link
Well-known member
Just curious if anyone knows at what distance the 3D effect of porros actually diminishes to the point where it's not noticeable?
I think it's a surprisingly long distance.
I just did some observing of overlapping fence posts through some neighbors' backyards with a tripod mounted Porro 8x and a roof 8x. I found that a fence post at a distance of 300' very obviously changed position relative to an overlapping fence post at a distance of 250' between the left and right sides of both the Porro and the roof. Those were the longest distances I had available, but given how obvious the parallax shift was even in the roof I expect it wouldn't disappear in the Porro until distances are well beyond 1000', perhaps even 2000' (for objects with the same 20% difference in distance). Maybe somebody with easy access to longer distances could make the same observations.
Henry