One must calculate the power draw of the camera. Without this I cannot answer your question as it may be too much draw from one single point, being that on 802.3af each connection can only handle up to 12.95W after traveling through the cat cable.
Lets say if the camera draws 1mp at 12VDC you are looking at 12 watts of power, adding another one to the mix would be double that and this is calculating it without the IR's operating.