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Mounting / Un-mounting Zeiss Contax or Nikon Rangefinder Lenses

It is easier if you understand the focusing helical for INTERNAL BAYONET MOUNT 50mm lenses is mounted IN the camera body.  This design allows for smaller and lighter 50mm lenses, as well as right hand finger index focusing on the focusing wheel (located on the right front top of the cameras).  Conversely, the focusing mount for the various EXTERNAL BAYONET MOUNT wides and teles (and a few large 50's) is in the lens, like most lenses. 

To mount an INTERNAL MOUNT 50  lens, 1st lock the camera's focusing helical to infinity by rotating it towards the advance knob, until it stops and locks.    Line up the index lug on the lens with the index point on the lens mount and / or camera body (at the 2 o'clock position facing the camera).  Insert the lens, and rotate it towards the advance knob or lever, until it locks.   To focus, push down on the locking pin behind the focusing wheel, rotating either the focusing wheel or the lens barrel, as you prefer.  To un-mount the internal mount 50, 1st push down on the spring located on the focusing helical near the infinity mark.  Rotate the lens towards the rewind knob until it stops, then lift out the lens. 

To mount an EXTERNAL BAYONET wide angle, tele, or large 50 lens, first turn the lens helical to infinity.  Now  lock the camera's focusing helical to infinity by rotating it towards the advance knob, until it stops and locks.   Take the lens in your hand so that one finder is depressing the lens lock on the lens.  Next line up the index mark on the lens mount (located in line with the infinity mark) with the next mark on the lens mount and / or camera body (at the 2 o'clock position facing the camera).  Insert the lens, and rotate it towards the advance knob or lever, until it lock.   Keep in mind this is an EXTERNAL BAYONET MOUNT lens, so the lens mount will go OVER the bayonet mount on the body, not INSIDE the mount like the smaller 50's.   To focus, just turn the lens helical.   To REMOVE, turn the lens to infinity, push down on the lens lock release, and rotate the lens towards the rewind knob or lever. 

Wide angle EXTERNAL MOUNT lenses shorter than 50mm may be focused by the lens barrel OR the index focusing wheel, whichever the photog finds preferable. 

DO NOT focus an EXTERNAL MOUNT 50, 85, 105, 135, or 180 lenses with the index finger focusing wheel -- the strain of it may damage the focusing mechanism.  


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Revised: November 26, 2003 Copyright  2002  Stephen Gandy. All rights reserved.    This means you may NOT copy and re-use the text or the pictures in ANY other internet or printed publication of ANY kind.  Information in this document is subject to change without notice.  Other products and companies referred to herein are trademarks or registered trademarks of their respective companies or mark holders.