Thanks for your comment! Actually this is done in Designer as well, I like Designer very much and seldem use Photo. As for me, I think Photo can't replace PS for now.
The digital camera is metal so it's simple to draw. Compared with plastic, wood or something else, flection on metal is clear and with high contrast, so just use Gradient tool, it can make matel look very realistic, you can add some noise to add details. I think Gradient tool in Ad is much better than that in Ai, I really enjoy it.
Metal wiredrawing effet is a texture, after I finish the gradient, then add a texture layer in multiply type,add a mask then.
Lens flection layer choose Screen type.
Hope this can help.
I will try to add a better background later, Thanks for your suggestions again.