LensRentals.com short, very basic article on shutter speed

Interesting how the simple two-way Aperture/Shutter-speed see-saw has now become a triangle, with ISO playing gooseberry in the middle.

I remember a time when you fitted a film in the camera and were stuck with one ISO for 12 or 36 exposures. Choosing an aperture or shutter speed seemed like a much easier decision in those days. All you had to do was count clicks on the speed selector and a corresponding number of clicks in the opposite direction on the aperture ring. Or vice-versa.