Denki-gai no Honya-san
What can I say about her? She has a certain depth that isn't there with regular shy or antisocial characters. She seems like she's just not all there. I wish I could sum this up more nicely, but she simply acts like she'd rather just not get personal, not out of shyness but out of a lack of will to. I share those feelings, so I understand her.
Of course, I'm just looking into this way too much, but hey, it's my headcanon.
She doesn't like talking, she doesn't like getting into situations, she handles customers like she would products on a conveyor belt. But she's not shy, she's not outright trying to not be there, in fact she loves being there. But not directly in the situation, rather a simple observer, there to watch but not play. Her camera is more than a tool to preserve moments, it's a security blanket, something to say "Hey, I'm here to watch, leave me alone". Again, it has to be stressed she isn't shy. She can talk to people just fine. But there's something she's hiding, past scars that made her learn it's better to be quiet and be thought a fool than shout and prove it. As much as she'd like to join in with everyone and get in as many fiascos as her friends, she just stands back and reminds herself of this.
Kameko's a lot more complex than she puts on, and she doesn't want to put more on than she needs to, because that leads to unnecessary attention. Ultimately all she wants to do is hide behind her camera and just watch the world go by, watching it from a distance like watching a car crash. And I feel her.