There is a difference between porros and roofs that is never mentioned, and is the reason i am sticking with porros. You get far better 3D vision with them
as the objectives are more or less twice as far apart. As magnifying flattens 3D effect you want the objectives as far apart as poss to compensate. Looking at trees and shrubs while spotting birds in them IMHO is more realistic
after all that is why we have two eyes. That said looking long distance or at flat surfaces (buildings eg) there will be no difference but that isn't birdwatching. It will be noticed up to say 100 metres. Not all porros however improve 3D, pocket or reverse porros make matters worse as the objectives are nearer than your eyes to be compact so its sort of a double whammy. I once looked through a pair of Pentax 16x24 reverse porros and there was hardly any 3D effect unless you where looking just feet away as the magnification was 16! naturally they were not very bright either.
Not sure why this is in the opticron forum but anyway here are my thoughts.
The 3D aspect has been mentioned before but I wonder if the effect isn't counter to what nature intended. By this I mean if your ipd is increased with porros your brain is working harder to pull the image together coherently especially at close distances. So a binocular that mimics the ipd of your eye at the objective end will be more comfortable and natural.
Comparing roof to porro of same spec and brand the porro image looks smaller. I wonder if this is an illusion or the roof image looking bigger is an illusion.
Nev
[QUOTE=dipped;934403]Comparing roof to porro of same spec and brand the porro image looks smaller. I wonder if this is an illusion or the roof image looking bigger is an illusion.[/QUOTE]
This might well be an effect of field of view which will tend to be wider in porros than roofs. A wider FOV often gives the illusion of lower power. I tested this by setting up two scopes with 30x eyepeices, one had a narrow FOV and appeared to give a much higher mag than the one with the wide FOV.