An older camera has a lens with a focal length of \(50 \mathrm{~mm}\) and uses 36-mm-wide film to record its images. Using this camera, a photographer takes a picture of the Golden Gate Bridge that completely spans the width of the film. Now he wants to take a picture of the bridge using his digital camera with its \(12-\mathrm{mm}-\) wide CCD detector. What focal length should this camera's lens have for the image of the bridge to cover the entire detector?