Is there any source that says that in order to make a bracha for seeing e.g., a sage of Israel, a sage of the nations, or an unusual animal, one must be within four amos of the person/thing? I found that the Aruch Hashulchan (Orach Chaim 234:8) says that when making a bracha on a Jewish graveyard, one should do so within four amos, but that if one is unable, he can make the bracha as long as he can see. Does the preference for four amos apply to all such blessings? And is there a source for this ruling?
I found the following teshuvah by R. Betzalel Stern, BeTzel HaChochmah 2:16:
Regarding someone who travels by airplane from Australia to Israel, and on the way flies over mountains and deserts...In my humble opinion, it seems obvious that as long as he has a clear view, even though he only sees them from a plane flying miles above, he is obligated to make the appropriate blessing.
He brings a number of proofs for this: in the laws of Purim, one who can see the city is considered part of the city, even from a distance; the prohibition to recite holy matters in the presence of an ervah exists as long as one can see the ervah, despite the distance; and the halachah regarding Mishkan Shiloh that one can eat kodshim as far as one can see it.
The ruling of the Aruch Hashulchan about Jewish graves seems to be based on the following: Although the Talmud Bavli says that this blessing is made by one who "sees" the graves, the Yerushalmi (Brachos 9:2) does not mention seeing but instead says "one who passes through" a graveyard. If so, it isn't seeing that obligates one to make a bracha, but actually passing through. The Aruch Hashulchan translates this into an ideal requirement of proximity of within four amos.