Servicing notes for Kodak DKL Xenon 50/1.9

Background :

“The lens ‘focus’ was right on my Kodak IIIS finder, but the image never gets right on the film. And when I use it on my Retina Reflex IV , the infinity image is formed before infinity mark. What happened? My lens has been serviced… ”

Kodak Retina IIIS and Reflex series (S, III, IV) have shared the same DKL lenses in use, thanks for the coupling mechanics added on it. The IIIS Range Finder coupling is done by changing the brass slope next to the rear element of the lens during focusing ; while on the Retina Reflexes user just focus as usual.

But later when IIIS, Retina Reflexes, and Compur shutter design were no longer popular, Kodak has shifted DKL lenses to use them on this Instamatic Reflex (using obsoleted 126 film). They have changed the lens design into a straight tube. You won’t find the old RF coupling brass slope at the back (I have seen this happen on late Xenon and late Tele Xenar). And this is why one can not simply use a “modified” non-Kodak DKL lens on Retina IIIS, because they are lacking the RF coupling function.



When service this lens (or other Kodak DKL lenes) , one should make sure the infinity on the lens AND the coupling mech are right. This, one should have at least a Retia IIIS to do this job, or having Retina IIIS and Retina Reflex (S/III/IV) at the same time.

Debugging procedure:

• Retina IIIS RF focus right but the image on film is not = the lens focus infinity adjustment is wrong.
• The lens forms clear image on film, but not coupling right on Retina IIIS RF at infinity = the Infinity Stop Set Screw is off
• The image and RF coupling are right, but the Infinity Mark is off from the pointer = The scale plate is off

Opening the lens simple ,

-Unscrew the center of the holding ring ( aka the inner sliver ring)

-Lift up the outer Name Plate Right

Then you can see the design is almost same as the modern standard: 3 slotted screws with washer underneath to hold the main lens body.


Slightly loosen these 3 screws and turn the slotted brass to make the lens reach the correct infinity with distant object. You can work out this with a Kodak Retina Reflex (S/III/IV) or put a focusing screen at the back of IIIS with Shutter open at B (Bulb ) .

This is the solution for (1) .

When these 3 screws/washers have been removed, you can take out the WHOLE brass lens unit from the focusing ring.

You will see a metal coupling bar that connects the focusing ring to the brass slope ring below.

When focused at infinity, the coupling bar will be stopped by a tall screw. This is the Infinity Stop Screw. You will find this screw can’t be takeout but rotated in an offset way.



Put this focusing unit back on IIIS camera, and set it at infinity, and turn this Infinity Stop Set Screw slowly until the RF image is right at infinity. This is the solution for (2) .

Reinstall the brass lens unit. Make sure the Focusing Guard Bar and the Aperture Bar have put into right place on the brass unit.

Reaffirm the image is sharp at infinity by checking with Retina Reflex (S/III/IV), or put a focusing screen at the back of the IIIS with opening the shutter at B using the method as mentioned for (1).

For (3) ,

When the focusing are right an infinity, slightly loosen the 2 slotted screws that hold the distant scale. It is just a metal plate. You can slight shifting it back to right place and retighten the screw.

The thin and thick version of Xenon 50/1.9 . They are optically identical in glass design and arrangement.




The thin version is actually for the Kodak Instamatic camera that uses 126 film . At that time Kodak has decided to let their DKL lens last stand on their instamatic reflex only. This camera , the Instamatic Reflex could be with 45/2.8 or Xenon 50/1.9. The 45/2.8 is another story, which focused by moving the front group of glass for focusing.

As you can see from the here, this thin version has the mechanical DoF replaced by the marks on the mount. There is also an index for (now obsoleted) bulb flash below it :



On the mounting side, the thin version has the RF coupling brass ring removed as well :



Both lenes can works on Retina Reflex SLR cameras (S/III/IV), but please don't put on the think Xenon 50/1.9 to any Retina IIIS . They simply don't wort and its possible to damage the coupling pin on the IIIs body (which works for focusing and frame selection)