That is a big advantage of the Zeiss SFL. They have a bigger optical box or what you call wider pupil sweet spots, so it makes it much easier for eye placement and avoiding glare.Could be that Swarovski thinks the NL's narrow pupil sweet spot for glare is good enough (it has been good enough for me since I found it, but obviously not everyone does find it.) I've noticed since then that almost all binoculars will show some glare if the eye is positioned too far from the eyepiece, but some have wider pupil sweet spots than others, so they get fewer complaints. Checking about 12 of my binoculars that I remembered as being good against glare just now I found that only one was truly glare free in the test setup I used for any pupil distance from the eyepiece: a Canon 10x32 IS.
"One of the signature features of these Zeiss SFL binoculars is how forgiving the eye box is. By “forgiving” I mean that they give you a fair amount of “cushion” concerning the placement of your face/eyes in relation to the eye cups in order to get a full and complete field of view without having those annoying black spots. In this regard, the Zeiss SFL binoculars offer one of the most forgiving eye boxes on the market today. Because of this, the viewing experience is remarkable because you aren’t in a constant fight trying to avoid black spots as you move across hillsides glassing for animals.
Eye box forgiveness is something not often talked about in terms of binocular features, but when a binocular’s eye box is not forgiving, you notice. A perfect example of this is the Swarovski NL Pure. These are some of the most impressive binoculars we’ve ever tested at Backwoods Pursuit, and are the top performers in our review. Personally, I’ve been using them for a couple of years now, and they are fantastic. However, their eye box is not very forgiving, which can be frustrating at times when they move slightly out of the “sweet spot” in the eye box making you fight black spots in the field of view."
Zeiss SFL Review | 10x30 & 10x40 | Insanely Good | Best In Class Ultralight Binoculars - Backwoods Pursuit
When we first considered putting together this Zeiss SFL review, we didn't really know what to expect. Zeiss Optics has made top notch binoculars, spotting