I hooked up my new audio technica atr55 to the mic port and shot some footage. Came out mono on playback. Rehooked up mic and noticed only left channel. What's going on?

Also went into settings on my GL2 and couldn't do anything to remedy.

Most mics, including the ATR55 (http://audiotechnica.com/guide/line/atr/ATR55.html) are single-channel (mono). It's operating correctly.

Will there be anything I can do later to make the audio a stereo sound in editing?

Yes. Most editors enable you to pan one channel to the other.

Remember that the purpose of a shotgun mic is to record a narrower sound field and tone-down other sounds. If you just want to record ambient sound just use your built-in stereo mic (which is really 2 mics).

I really appreciate that info. I have read many posts about the built in mic being a bit distorted. Do you use a shotgun mic for voice when shooting scenes, say on a boom like in film production?

Generally yes, a boomed shotgun (if you have sound assistance) is fairly standard. Depending on the situation, lavelier mics are also common.

Wander over to our Now Hear This section to chat and research sound.

Sorry to bother you but now I'm having this problem when recording footage to dvd. Anything shot using my shotgun mic plays on my win media player but not on my home dvd player. The footage using the built in mic plays just fine on the home dvd player. What is going on?!!!

Jay,
I don't think anyone will be able to offer you much help; you've not provided nearly enough information. I suggest that you provide more details of how the footage was edited, how the dvd was created, etc. in the other thread that you started (http://www.dvinfo.net/conf/showthread.php?s=&threadid=38929). It is unlikely that the problem has anything to do with your camera or mic.

Figured it out. My dvd player is an older model like I was told. It chooses one or the other left or right channel exclusively and chose the blank one. Remedied. Thanks for everyone's input.

Jason