More Progress on Camera

The above section shows where I am terminating the model.  

I outlined the back on the camera to model the curve in section. 

I then used this outline and lofted two sections of the back together.  

I created a surface out of curved planes to cap the edge of the camera.

I began to model the front curve of the lens.  I now need to figure out a way to tim the rest of the beginning of the lens.  I attempted the 'trim' tool but it will not allow to me to cut a lofted plane.  Any suggestions?