M42 Lens to Canon EOS AF-confirm adapter

This adapter allows the use of M42 (Pentax Screw Mount) lenses on any Canon EOS camera body. Such lenses are made by Praktica and Zenit and are also easily found on the used lens market from such manufacturers as Pentax. Although all M42 lenses are manual focus, this adapter retains the operation of the camera's electronic "in-focus" indicators - a green circle appearing in the viewfinder and an audible "beep" - to confirm best focus. If the shutter is 1/2 depressed and the lens manually focused, the camera will indicate when best focus has been achieved. Simpler M42 adapters lacking electronic contacts do not allow the camera to provide any electronic focus confirmation and focus can only be judged by observing the image on the viewfinder screen. This can be quite difficult, especially with slow and/or wideangle lenses.

Since M42 mount lenses have a manually operated aperture, camera modes which control exposure by automatically adjusting aperture are not available. However full autoexposure operation is available in Aperture Priority mode and the camera can also be operated in manual exposure mode using in-camera metering. In manual mode the shutter speed is set on the camera, while the aperture is set on the lens. In Aperture priority mode the aperture is set on the lens and the camera will automatically set the shutter speed to provide the correct exposure. M42 lenses mounted on EOS bodies via this adapter do not interfere with camera operation and allow the use of mirror lockup.

Written by Bob Atkins "How to use" by Bob Atkins

COMPATIBILITY:

NOT compatible with EOS 30, 30V, 33V, 650D, 5D MkIII