It would be helpfull i guess if you mentioned what you want to do with the camera?

Well i made my camera with the basics of cos and sin, i believe theres some other way but here it goes:

With a circle of radius 1 and origin 0,0, Cos(angle) and sin(angle) will give you the (x,y) coordinates to any point of the circunferance of that circle correspondingly (so cos for x and sin for y).
So now for a moving origin and a radius that's not 1 you have, origin(x,y) - ( radius_of_the_circle * cos/sin(angle) )
You also have to add the angle difference to the pan of the camera to keep focus on the target if you want it to.

With that formula you can pan or tilt around the desired target, for zooming in and out you can make the radius a variable and adjust that correspondingly, i believe it is unnecessary to say that you need to do all that within a infinite loop.

Hope that helps and it's not too confusing, i'm not an expert at math by any means aswell but that worked pretty darn well for me, cheers.