Casual Friday. What a concept. It's almost outdated, as many offices are casual every day. Do photographers get to have a Casual Friday?
I don't have clients, so I don't have that pressure on me when I shoot. Some of my friends are wedding photographers. Although they claim to enjoy it, I wouldn't care to put on a suit & tie during the weekend to photograph an event. Seems like those clothes would just get in the way.
On another extreme, my friend Alan Hess is a concert photographer. His office is in front of a bunch of people who paid good money to see a show. When he goes to work, he wears black to try not to draw attention to himself and stay out of the way of the show. He's also tall, so there's potential for quite a bit of ducking. Probably helps to have comfortable clothing.
Even though I don't have clients, I've found that my appearance still matters to some extent. If you want to get access to a place, it helps if you're not wearing your death metal t-shirt or some inappropriately stained shorts. People like to judge you. One of the easiest and most obvious things to use when sizing up a person is their appearance.
If you like traveling out into the wilderness for your photography, you're in luck. Animals are not as judgmental as humans. Otherwise, you need to dress for the level of judgment that you're likely to encounter. For wedding and concert photography, you're trying to blend so you aren't noticed. It's the event that's important. When you need to gain someone's trust, your choices may vary. Doesn't mean that you can't be comfortable, or even casual. It just means that you need to be presentable for the circumstances.
Even on Casual Friday, there's still a dress code. Probably best to avoid anything plaid.
Casual Friday in the Studio
You know, I can't tell a lie. This is actually the most she wore during the whole shoot.