Chinon 35F-MA
While the Chinon 35F-MA may not be the only camera to use an infrared beam for focusing it is likely the most prominent of implementations. On either side of the viewfinder sit a giant IR transmitter or receiver. When the shutter is half pressed the camera sends out a narrow beam of infrared light that bounces off anything in its immediate path to be recorded by the receiver. Using the delay of the pulse the camera determines which way the lens focus needs to move to match. Once the pulses and the focus setting match the IR no longer transmits. In the bottom of the viewfinder is a needle that points to icons that represent the rough distance that the autofocus system has determined. If no pulse returns to the receiver it will set the focus to infinity so if you point the camera at something that causes the beam to not return such as glass or a black hole it will default to infinity. Fortunately you can see that this is happening with the needle indicator and perhaps use the method of focusing on an object a similar distance away with a half press of the shutter and then recompose. The focusing has a particular sound like an assembly line robot but is quite fast and accurate and because it is active it works in complete darkness which would make this camera fun to use with flash in the dark…SURPRISE! Once again I feel like a broken record but I have used expired Kodak Max 400 its not as if I’m going to throw film away.
I love that the camera uses two ubiquitous AA batteries. Interestingly the camera also has a 3V power input port although I haven’t seen the need to try and find a way to use it, I think the idea was that you could use an external power pack for faster flash recycling or to shove it somewhere warm in cold weather.
