KODAK FRONT-CELL FOCUSING LENSES
Lenses in most Kodak folders are front-cell focusing, since these cameras do not have rangefinders and this mounting method is the simplest and cheapest. Understanding their structure makes disassembling and cleaning them easier. If you do not intend to clean the shutter, you can do these operations without removing the shutter from the camera. The diagram shows a four-element lens in three groups. Other Kodak lenses had three elements in two groups; the structure of these is the same, but without the double-threaded sleeve.
 
  • To remove the front cell, unscrew the stop screw, which is either slotted or hex-shaped. Rotate the cell inward until it is stopped by the shutter speed dial/name plate. Note and record the foot reading (focusing scale) on the front cell in its relation to the stop pin. Unscrew the front element slowly lifting slightly, and note the relation of the focus scale to the stop pin as the cell comes free. Record this information also.
 
  • Unscrew the sleeve containing the middle element. This may have slots in the rim to allow you to use a spanner. If no slots, try a rubber stopper. If that doesn't free it, you will need a lens wrench, typically about 1 1/8. If you do not intend to work on the shutter, be careful to keep the knurled speed dial and name plate in place, since these are usually held on by the flange on the threaded sleeve.
  • Remove the rear cell in the same way.
  • Dirt is likely to have mixed with the lubricant used for the front cell so clean all metal surfaces with naphtha and wipe them with a clean paper towel. If you don't do this first, you risk carrying this abrasive mixture to the optical surfaces as you are trying to clean them with Windex.
  • Clean the optical surfaces in the prescribed way.
  • Determine if you need to do internal shutter maintenance, then do it following the prescribed procedure, or:
  • Clean the outside surfaces of the shutter body, speed ring and name plate with naphtha.
  • Reinstall the rear and middle cells until they are snug. Tighten the middle cell with a lens wrench, if you have one, otherwise use a rubber stopper.
  • Place a very thin coating of lithium grease on the front cell threads, keeping it well away from optical surfaces.
  • Placing the front cell in the sleeve with the focus scale in the same relative position it was when it came free, try to start the threads in the sleeve. Continue screwing the front cell into the sleeve until it contacts the speed/name dial. If the scale marking nearest the stop pin in as it was when you removed it, go to the next step. If the scale mark in relation to the stop pin isn't the same, you have not started the threads correctly. Remove the front cell and turn it 90° and start threading. Repeat this adjustment procedure until the scale marking is correct. Having the front cell in the correct position to the rest of the assembly is critical for focusing accuracy.
  • Back the front element out until the Inf position of the scale passes the stop pin, then reinstall the stop screw.
 
  .
 
01/24/2003 19:42