FED 6.3/100 lens LTM problem

[john341]

What is it with the 100mm FED 6.3 l3ns? I cannot get rangefinder alignment with this lens. I seems that the lens mount is too thick as the distance scale does not finish on the top of the camera but to the side. I have tried this lens on many ltm bodies and cannot get a match. Does anyone have any experience with this lens??

 

[photovdz]

It's normal..; it suppose to be somewhere like 10:30 or 11 o'clock...
make a test roll... as those lenses are not standard calibrated... you have to match them to certain fed body (and vice-versa)...

 

[varjag]

Yes, the lenses and pre-war FED bodies were supposed to be matched for each other in a workshop.

 

[jc031699]

Quick note from my cleaning of my newest lens: FED 100mm f6.3
I could not find any other online resource at all for how to do this. It was pretty straightforward in the end.
It opens by taking out the 2nd ring in from the back. This allows the optical unit to slide out the front.

There are three grub screws that hold the focus ring in place. Taking those out allows the ring to slide off the front.

Unscrew the front and rear lens units and clean them. Each of these is a cemented doublet. The FED lens is a four element in two groups lens. Not sure if this means it's a topogon type design... (the canon 28/2.8 and orion-15 seem to have a similar arrangement) These lenses cleaned up nicely.

The aperture ring can be taken off, by unscrewing the two threaded aperture control pins, but this can/will release the aperture blades which will fall out if you are not careful. You have to use a cork or some other cylinder to press the aperture blade assembly into place in order to replace the aperture ring and place back the threaded pins. The surfaces between the aperture ring and the optical unit may need cleaning/light regreasing.

The helicoid will unscrew completely if you take out the small silver screw in the side of the focus unit. Be sure to mark the helicoid so that it can be replaced into the right starting point. I used some NGLI 2 grease, probably could have used even heavier to remove some play in the helicoid.

Interestingly, the rangefinder cam is spring loaded, and can be pressed out the back gently for cleaning/greasing of the sliding contact surface.

There were tons of shiny surfaces that I blackened with India ink to decrease internal reflections:
1) outer shiny silver inner diameter of aperture ring
2) surface of front lens unit
3) inner surface of optical unit front
4) inner surface of optical unit back
5) all inner surfaces behind the rear lens unit - 2nd ring from the back, 1st ring from the back, inside of focus unit, inside of rangefinder cam
7) aperture blades front and back with sharpie (like Brian's I-61 mod) - they were shiny blue to start

The first ring from the back comes out easily, but I'm not sure what it does as part of the rangefinder cam assembly.

I hope all of this, plus my Leica FIKUS clamp on hood will help to reduce the flare that I've seen on posted images.
It is super tiny, very cute, and solid brass.

 

[Valkir1987]

It's an old 'Tele Tessar' design lens. It needs to be collimated and adjusted by a workshop to work on a Leica or any other L39 body. If I remember correctly, the ring that touches the rangefinder cam can be adjusted at the right height.

Please do not remove the 'shiny blue' of the aperture blades with a marker. A limited amount of lenses with a blue aperture was made for the Fed 1C series. Theses lenses are rare and rather valuable. Most 'regular' pre war Fed 100mm lenses come with black aperture blades. This is more a collectors lens than a performer.

You can find the optical design here.

Pre-WWII Lens FED-36 6,3/100 & viewfinder FED 100 mm - USSRs Phototechnics

The FED-100 100 mm f/ 6.3 Lens. Specs. MTF Charts. User Reviews.

 

[jc031699]

It's an old 'Tele Tessar' design lens. It needs to be collimated and adjusted by a workshop to work on a Leica or any other L39 body. If I remember correctly, the ring that touches the rangefinder cam can be adjusted at the right height.

Please do not remove the 'shiny blue' of the aperture blades with a marker. A limited amount of lenses with a blue aperture was made for the Fed 1C series. Theses lenses are rare and rather valuable. Most 'regular' pre war Fed 100mm lenses come with black aperture blades. This is more a collectors lens than a performer.

You can find the optical design here.

Pre-WWII Lens FED-36 6,3/100 & viewfinder FED 100 mm - USSRs Phototechnics

The FED-100 100 mm f/ 6.3 Lens. Specs. MTF Charts. User Reviews.

Thanks! Yes, I am planning to shim the optical unit to see if I can get the RF calibrated without touching the cam.

Fortunately all of my blackening steps are totally reversible. The sharpie comes off with an alcohol wipe, and so does the India ink. All of these are pigment and not paint or chemical removal of the bluing.

I intend to use this, it has zero value to me as a collectible.