On Monday, I gave you this mysterious object to identify:
The other side looks like this:
It was correctly pointed out that the base looks like it would fit on a film camera where the flash might go. But still, what is it?
The give-away might be what is on the end of the device, a scale to convert from feet to meters. Why would you need such a thing?
This is an old-fashioned rangefinder. Back in the day, cameras didn’t have autofocus. And not all cameras had through-the-lens focusing, either. You had to set the focus based upon what you already knew to be the distance from the camera to the subject.
In order to know that, you needed a rangefinder. Some cameras had them built in. Or you could buy them separately.
Rangefinders work by taking two views of the subject, via the two window at the front of the rangefinder. Then the user looks through the eyepiece on the back and turns the dial until the two images overlap. When they do, the correct range shows up on the dial.
Then, you simply set the focus on your camera to whatever it needs to be. If you camera’s lens is marked in meters, you can use the converter on the end to get the correct distance in meters.
Then, aim the camera and *click*! You’ve taken a perfect, in-focus picture.