Confusion about officer's field uniforms...

[Synthesis]

Something I've always been confused about, and am hoping someone can shed some light on.

Unlike Service and Parade uniforms, field uniforms don't seem to be very commonly portrayed in photographs, and seem to have lot of odd variations.

I'm not talking about combat uniforms/camouflage that would obviously vary depending on where you are. I'm talking about the garrison-style drab olive tunics, similar to what enlisted men would wear with their pilotka, rather than visor caps.

From what I've gathered, officer's would wear olive-drab colored visor caps (rather than the normal service caps) with these uniforms. What I don't get is the details--the olive drab uniforms might have either gold service-style buttons, or olive-colored buttons (like the cap), branch-color collar insignia, olive-colored insignia tabs, or just a simple olive-colored pin through the collars.

I'm pretty sure the shoulder boards are brown, with colored stripes and olive stars. Black high-boots were worn too, I think, rather than combat boots.

Could someone more knowledgeable set the record straight, especially with any pictures?