From B&H Photo
B&H Photo has posted a nice article about the coming of the original Canon EOS 5D camera body. At the time, it was the first full frame camera that was “affordable”.
A snippet from the article
“Most photographers in the mid 2000's had developed their eye using 35mm film cameras. When they attached a 50mm lens and looked through the viewfinder, they expected to see a 50mm focal range. However, nearly all the DSLR cameras available at the time were using APS-C-sized sensors, which introduce a significant amount of crop factor. The classic nifty fifty is cropped to 80mm. This compromise threw many people off, and proved to be a persistent nuisance.”
The original Canon EOS 5D was the first full frame camera I ever used. I borrowed it a lot from the photo store I worked at, I just couldn't go back to my EOS 40D, which was a great camera in its own right. I didn't actually own a full frame camera until late into the life of the 5D Mark II, as I was using APS-H for a long time with the 1D3 and 1D4.