FAL
Good question. I don't know... I can one guess.
Seeing that the IR illuminator is on the side of the scope and only about, what, .5" in diameter it is too small to illuminate the entire field of view of the scope.
That coupled with it being a 1st Generation scope, meaning that due to the optics/design, there is distortion at the edge of the field of view. Look through the scope during the day (with the pin hole cover on!!! and you will see the distortion I'm talking about. The view is almost like a semi-fish-eye lens. That is one of the "faults" with 1st generation. But one I can live with.
Also, I've used my Surefire 6Z with an IR lens cap while looking through the scope. That lit up the world! It illuminated the entire scope field of view.
Keep in mind that this is a NV Scope... and one of the things is that you want to use NV so you can see but not be seen. Even that little bitty IR Illuminator can be seen from I know 200 yards... we check that specific point out.
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Schmit, GySgt, USMC(Ret)
NRA Life, Lodge 1201-UOSSS
"Si vis Pacem Para Bellum"