Think again that if your parts could be manufactured from plastics If you want to produce camera parts . I think you can draw your part with cad cam program and you can get small quantity rapid prototyping parts from plastic for example epoxy. Or you can order a rapid prototyping mold for to produce your parts with carbon graphite powder and epoxy blend.
Rapid prototyping is fast and cheap.

Best ,

Mustafa Umut Sarac