What kind of camera do they use?

I use a HP digital

It's not the camera that matters . It's the tecnique : for advertisment , street adds mostly , they use slides instead of films . But then again with digital photo and everything , any SLR shold work , provide it has at least 6 mp's and a wide angle lens .

It is high time you knew business tricks!

any digital good as* camera.

Usually for print, the company will use a high quality camera to capture the product. Besides the camera, there are also many other factors such as lighting, the background, the angle of the shot, accessories that goes with getting a good picture. It all depends on the marketing message that the company wishes to convey. If you are referring the sample pictures that the company claims were taken by the camera for sale, then it all depends on the campany. Some companies just take the pictures from Stock Libraries and others may go to the extent of using actual photos taken by the cameras. At the end of the day, you should have your radar on high alert when you see any ads because basically, most are selling you a "dream" or an "ideal". Some companies have disclaimers stating that the photos are for illustration purposes only. Turn on your reality check and get back to ground zero.

They generally use large format cameras because the purpose is to show you the camera, not what it does, and large format cameras produce the best definition. Now, those cameras are often used with a digital back, but some still use slide film for the hard copy it produces.