i adjectives - Is anything implied, but not written, in this nominalization "遠くを見つめる"?

(1) 遠い所を見つめた。

I think means:
"He was looking at some distinct location in the distance."

(2) 遠くまで見つめた。
(3) 遠くを見つめた。

I think both mean:
"He was looking off into the distance and looking for anything unusual."

So, what is the grammar of #3?

(3) 遠くを見つめた。

Doesn't "を" require an object?
Has "遠く" been nominalized somehow?

btw:
I heard #3 in an 男っぽい dialogue.
Maybe the words that are needed to create proper grammar are not spoken?

Answer

デジタル大辞泉 says 遠く is a noun which means 遠いところ. So yes, it was somehow nominalized and lexicalized in this form long ago. At least we can say 遠くから来る, 遠くに行く, 遠くへ行く, 遠くを見つめる, 遠くで音がする, 遠くの国, 遠くがよく見える, and so on. 近く works in the same way.

The list of similar expressions is very small, according to this article. Here's the list:

• 古く (old time), 早く (early time), 遅く (late time)


• 近く (nearby place), 遠く (distant place), 深く (deep part), 高く, 広く


• 多く (much), 詳しく (detail), 正しく (right thing)

Note that many of these are related to time or distance. Also note that many of these are only used in certain fixed expressions, or are acceptable only when used with certain adverbs (See the article). It seems that 多く, 近く and 遠く are exceptionally less restricted.

遠くまで見つめた is different from 遠くを見つめた, in that the observer looked at both 近く and 遠く in the former sentence.