WriterCJ
Well-known member
Calvin,
I suppose I was remiss in not stating that the rim of the eye cup should be in the rotated down position.
Still not very scientific... but shining a light source through the objective, and moving a piece of plain white card back and forth at the eyepiece until the circle of light on the card is at its smallest and brightest gives a very crude measurement (bendy plastic coated wire and a ruler) of between 14-15mm to the edge of the fully retracted eye-cup. There is perhaps 1.5mm (again very crudely measured) between the ocular surface and the rim of the fully retracted eye-cup.
If (big if) I'm on the right track here that would put the physical eye relief of the binocular somewhere between 15.5 and 16.5mm (which kind of tallies with the result of my earlier, ass-backward approach of measuring the distance between the ocular and the rim of the fully extended eye-cup), and a useable eye-relief somewhere between 14-15mm.
Again, let me qualify, these measurements are a) very crude and b) I'm not even sure the approach is valid for eye-relief measurement. The actual figures could be significantly different -- although it looks like the 19mm quoted on the box is perhaps a bit of a stretch.
Are there any 10x42 bins out there with 19mm eye relief?
Anyway... I hope all that is in some way useful.
Cheers,
Calvin!