I am concerned about the pickpocketers in Barcelona.?

I am an experienced traveler, aware of how to dress, etc. How serious is the pickpocketing (which I will only be carrying is my small video camera in Barcelona?

Been to Barcelona twice, never saw a pickpocket, but that doesn't mean you shouldn't be careful. One thing I'd like to clear up. Someone said keep your wallet in a front pocket, not a good choice, that is the first place they go for. I wouldn't carry a wallet at all. If you take the money and credit card you need for the day and keep it in a zippered, velcro or buttoned pocket in a shirt or inside coat pocket you will be fine. If you want to take more money use a money belt or a leg wallet, assuming you are wearing long pants of course. The best time to travel is in Spring or Fall as the pickpockets are much less active at these times. More good advice can be found below.
By the way, don't miss the trip out to the monastery of Montserrat, it is fantastic!

they do have problems with it over there, but in my experience there, i have not really found it that much more excessive than other big cities. you just need to be very careful with your things. i wouldn't worry too much.

if taking a bag, perhaps an over the shoulder one, that you can keep one hand on whilst you wear it. and if you have things in your pocket, make sure they can be zipped up etc.

My friends had their passports and wallets stolen in Barcelona, even though they were being extremely careful! Another of my friends caught a pickpocketer in the process of theft and scared him off. There ARE a lot of pickpocketers in Spain (and elsewhere in Europe, notably in the large cities), don't let anyone tell you otherwise!

My advice is to not keep ANYTHING in your pockets--front OR back. Pickpockets want you to keep things in your pockets because they are trained to pick your pockets! Use a money belt that you wear under your shirt, or carry a purse/sack/bag of some sort with you that you keep zipped at all times. I would even recommend buying a small padlock to make sure your zippers stay zipped.

If young children come up to you and ask if you need help with directions, say no and walk away quickly.

Carry your wallet in your front pocket, or just carry cash.

I visited Barcelona about a year ago, full of worries like you mention. But I had not a single encounter with any criminal activity, day or night. I was even on the public beach after midnight. Everyone was just cool and laid back.
So just be sensible, keep wallets/purses/cameras out of sight like in any big city, and you - hopefully - will have a pain-free visit like I did.