Idioms and Phrases with far afield
Wide-ranging, at a distance, as in I started out identifying wild mushrooms, but since then I've gone far afield in other branches of botany. [c. 1400]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.