[ㅔ] and [ㅐ] are being merged into [ㅔ] in modern standard Korean(Seoul Korean) and are completely undifferentiated in southern dialects. Some people say we don't differentiate the two, but some people do differentiate. Elderly people(over 50's) in Seoul pronounce/differentiate the two in general. I'm not sure if they all do though. http://www.korean.go.kr/hangeul/cpron/02_vowels/02_learn_07.htm Click [에] or [애] on the left side. You can listen to the pronunciation with seeing their lip shapes.

Aa a native Korean speaker, I can't tell the difference between ㅔ and ㅐ. Yeah, it doesn't really matter.