To have a list of rangefinder cameras, see the Category: Rangefinder.
Rangefinder cameras are those that focus using some sort of coincident-viewing distance-determination mechanism, called a rangefinder. The most common form, as used in cameras like the Leica and other classic small 35mm cameras, is to use a prism and mirror arrangement between two viewing windows. Small adjustments in the angles of the prisms will align two superimposed images -- when the images are aligned the distance can be determined accurately by a simple mechanical cam. With a large enough rangefinder base, this type of rangefinder can offer extremely accurate focusing. Such rangefinders have been used in 35mm cameras, such as those made by Leica, Canon, Nikon, and others for many years, and also in larger-format cameras such as medium format folding cameras or rigid cameras like the Mamiya 7, and even some early Polaroid cameras.
Other styles of rangefinder do exist, such as the electronic variety found in the Contax G1 and G2 cameras. In general, "rangefinder" focusing is often used to describe any focusing mechanism that doesn't view directly through the taking lens (or an identical copy of that lens, as in Twin Lens Reflex cameras).
- Very accurate focusing.
- Easy to focus in low light.
- No mirror slap.
- Relatively quiet operation.
- Short shutter lag.
- No viewfinder blackout.
- Use of filters does not affect picture taking process (compare with IR filters on SLRs, for example).
- Parallax problems with nearby subjects (though higher-end rangefinders usually have parallax correction built in).
- Accessory viewfinders are required for wide, ultra-wide or tele focal lengths (depending on the camera).
- Rudimentary depth of field control if any.
- Nearly impossible to use a polarizer.