Looking at APM binoculars. 90 degree.
Considering both 100mm and 120mm.
I am asking what difference in perform is seen between the Semi APO and the SD APO.
Within the Semi APO is there a gain in moving up from the 100mm to the 120mm, both being the Semi apo.
Or is it best to go with the 100mm SD APO.
Truly asking comparison of Semi apo to the more costly SDapo in the 100mm series.