Hello mgv410,
I own a Zeiss Fl *x32 which has an 8º FOV. As I recall I do not recall seeing this optical artefact. However, as tomorrow is supposed to be overcast, I may try to reproduce it.
Happy bird watching,
Arthur Pinewood
I've seen this effect before on many bins including the ZR. In fact previous readers of my reviews will catch me whining about stray light in all sorts of bins.
I just took my ZR ED1 8x43, Zeiss Victory 8x40, Zeiss FL 8x32 and Zeiss FL 7x42 out to check in the low evening sun (it was overcast earlier) at 5:30pm in Seattle.
Sun is about 40ish degrees above the horizon and looking 40 degrees up at a Douglas Fir (darkish background) at 30 degrees to the sun I can see the stray crescents in all four bins opposite to the sun.
The ZR ED1 has the biggest effect. Then the Zeiss Victory 8x40. Then the Zeiss FL 8x32 and then Zeiss FL 7x42 though the latter two are close. I'm impressed the 8x32 is that good with a small exit pupil. They do have an interesting beveled "objective lens hood" that may help).
The magnitude of this effect seems to have a lot to do with how you align the exit pupil of the bin and the entrance pupil of the eye with bins tipped upwards. THe usual problem is that you tilt you head up somewhat and then you rotate your eyes upwards so they are no longer centered.
I suspect if you have perfect style (i.e. the bins are always 90 degrees to your face and pointing directly at the target so you don't rotate your eyes) and the exit pupils are centered and the IPD is set right you may not see this effect.
The only bins I have that I thought were really immune to this effect are my Nikon SE. But I just went out and tried them in the same test. The 8x32 SE with a 7.5° FOV shows the effect rather too well --- actually worse than the FLs and I think worse than the Victory even after fiddling with the IPD to make it "too big". But the 10x42 SE if you get the IPD right shows the least effect. There's still some there but it's the smallest in this test set.
So as I always point out: all bins are compromises.
Just keep in mind what parameters your trading off for what: stray light is usually the last thing to get down to a minimum.
And one thing I can be sure of is the ZR ED2 won't be a panacea. I hope they'll be good but I suspect the level of expectation amongst some folks is just way too high.