"I want to get fundamental knowledge about the way consumers choose and use products in a market"
If your product is used socially, you're going to get a very artificial view of its role in people's lives if you ask them questions among a group of strangers surrounded by cameras and one-way mirrors. You'll get a much better answer and an instinctive grasp of consumers' lives, if you use...
As the name suggests, this is where you hang out with a group of consumers who’d be hanging out anyway. If your product is a soft drink, arrange to meet them somewhere they’d be consuming it anyway. Put away your notebook and join in. Observe with all your senses. What does the place look like, smell like? What are the textures you’re feeling? What are the rituals of serving, assessing, consuming?
This is the essence of one-eyed research: getting in amongst your consumers and seeing, hearing and experiencing what they do. After the hangalong, you’ll want to sit down with a few of the group and probe the reasons they did or said certain things. But now you’ll be doing that with a real sense of purpose.