additional information:
The swaros have the best resolution (not noticeable at the center, more near the edge). However the "field flattening" it uses to accomplish this comes at the cost of 'depth of field'. The swaros also have a very light (little resistance) focus knob, with aggressive adjustments. The end result with the swaros, is that I keep fiddling with the focus to look at the thing I want to look at. The razors are more pleasant to use - the most "invisible" binoculars I have used.
Last edited by Grady8541; 11/07/19.