Zeiss ikonta 520/2

[stefan lehkyj]

• I'm just in the process of starting to use this again, Ikonta 520/2.
  After cleaning, and screwing the front lens back on, I'm not sure if the lens is in the right position. First time it went back on fully the 10ft mark was at the top, second time the 3ft mark is at the top.
  Which is correct or should it be another number? How do I set it correctly?
  
  Thanks in advance
• 

 

[Donald Qualls]

Many if not most front cell focusing lenses from this period had multiple thread starts. This accommodated being able to orient the focus scale without the very costly synchronized threads that would guarantee that orientation. It also allowed a fast pitch thread, to get from infinity to closest focus in less than one turn without an expensive and mechanically weak skip thread. Since focus is determined by the depth dimension between the front element and the second one (for triplets like this one and Tessar types, at least), as long as that front element goes to the correct depth the focus will be right.

If the element stops at the wrong point (it should normally reach the infinity mark when all the way in) unscrew it and keep turning counter-clockwise until you hear/feel a click, then screw back in -- this will switch you to the next thread start. If still not right, repeat this process until the scale marker is on the infinity mark with the element fully in.

Then verify the focus (aperture wide open) with a loupe, frosted glass or plastic sheet at the film plane and the lens locked open on B (with a locking cable release). Infinity should be critically sharp for objects at least half a kilometer away.

 

[stefan lehkyj]

Donald
Thanks for the reply, thats great info and I have just sorted the lens. It is now fully screwed in and stopped at infinity.

Further to this, I have read that there is an all round shooting setting combination, other models of ikonta have red dots on f/stop and focus ring to determine this, do you know what the settings are for this model?

 

[Donald Qualls]

I don't know offhand, but the red dots (usually one on the aperture scale and one on the focusing scale) were to indicate best hyperfocal setting -- usually it was close to f/11 and for a 105mm lens the focus ought to be set close to 4 meters (12-13 feet) to give focus from about 2 meters to infinity (you may find a set of "brackets" by the aperture scale that will give this information). This is not "best all around" setting, this is a "treat your adjustable folder like a box camera" setting. Google will find you a complete depth of field chart that will be more useful (should be the same for any lens of the correct focal length on the same film format) -- among other things, it will include hyperfocal distance settings for other apertures than f/11.