The Canon EOS (Electro-Optical System) and the EF (Electro-Focus) lens mount have been the standard of Canon SLR and DSLR cameras since 1987. This neat video showcases 30 years of evolution in just 90 seconds.
Canon chose the "EOS" name in reference to Ēōs, Titaness and goddess of the dawn, a reference to the dawning of autofocus technology. The beauty of the EOS (and EF) system is the longterm compatibility; I can take any of my EF lenses and drop them on my 1V, a flagship film camera released in 2000 that was the foundation for the current 1D series. As a side note, if you think the 16 fps of the 1D X Mark II is impressive, you should see a 1V shoot 10 fps while physically moving film through the body. When the 1V was a bit too loud for some applications, I bought a used Elan 7 on eBay for $15 and was up and running as soon as I put a battery in it. I personally think it's a rather impressive achievement by camera companies (Nikon as well), as it's almost unheard of in other realms of tech for such a system to be the standard for over three decades. Check out the the evolution of the EOS line in the video above!
[via Canon Rumors]