Unless you are using a very old Pi Model A or B, you can use the I2C Bus 1 (GPIO 2 & 3, physical pins 3 & 5) normally with the RPi Camera attached and working, just enable the I2C in '/boot/config.txt' as normal.
I2C Bus 0 is used on some Pi models to control on board functions such as power supply voltages, etc, and is normally controlled by the GPU, as far as I know. It is also used for "Hats", add on boards for the Pi that connect to the GPIO pins such as the Sense Hat
through physical pins 27 & 28.
It also controls the Pi Camera through it's own connector.
Hope this helps,