Here, I cut out the camera and the tripod, laying them on the road background. I changed the perspective of the tripod screw to make it fit the camera better, then fixed up the edges of the camera and the red-color reflections from its previous background. I also added a grey gradient strip to the bottom of the camera to give it a better perspective.
After setting the camera on the tripod, I copied the outline of the entire thing and filled it with grey on a seperate layer. I used distortion, guassian blur, and opacity change to make it look like the camera and tripod's shadow. I also used the pen tool to lengthen the shadow's legs to make it more realistic.