Nomad Z
Well-known
Mentioned in another thread, I've been considering converting my pre-war FED 1 to use later lenses. The early FEDs don't have the correct lens registration - the distance from the film plane to the mount is too short, so the trick is to move the mount away from the body by the requisite amount.
Another thing that differs is the start of the M39 thread in the mount. If you fit a later lens, the focus and aperture index marks end up way out of position. You can turn the mount in 90-degree steps (the 4 screw holes are equispaced), but you'd then have to machine a recess in the new quadrant to ensure that the underside of the mount doesn't snag the rangefinder arm. To avoid machining the original lens mount, a mount for a later FED 2 was dontated to the cause by a pal.
While taking measurements to work out how much the new mount needed to be shimmed by, I noticed that the FED 2 mount is thinner than the FED 1 version, by about 0.3mm. This meant that, whatever measurements I took with the FED 1 mount in place, I'd have to add 0.3 to the thickness of the shimming. I also found that there was a pretty large discrepancy at each side of the mount. The higher side was where there was more paper shim (as originally fitted), so I took all of the shims out and fitted the FED 1 mount directly onto the metal of the body shell. The high side was still higher, but still low by about 0.35mm. The low side was about 0.3mm or so lower again.
So, to get the FED 2 mount to land at the correct registration, I needed a shim 0.65mm thick, with some extra shimming of about 0.3 at the low side. Rather than cut up bits of drinks cans (handy stuff - 0.1mm thick, and cuts easily with scissors), I elected to make one on the lathe - much easier to get a precise fit around the mount, and to control the thickness.
The photo below shows the camera with the mount removed, with the FED 2 mount and shim below. The paper shims are nearby - I cut the one that was originally circular in half, since I expected to need this on the low side. Note that the new shim has a bit cut out to clear the rangefinder arm. I found that I didn't need to remove any material from the FED 2 mount. There is also a sliver of drinks can in case I need it.
At first I tried it with two paper shims, but it was still too low. Then I tried with three shims, plus the sliver of drinks can (next to the paper shims), and this was too high. The three paper shims on their own seem to have got a pretty good balance - both sides are just about the same.
I haven't run any film through it yet, but setting the lens to infinity gets good alignment in the rangefinder. Measuring the registration is quite fiddly. I used a digital caliper and found that the easiest way is to set the depth thingy to a fixed amount, and move it down onto the pressure plate until the caliper stops at the lens mount. With a desk lamp shining in, you can see the pressure plate move a little if the depth on the caliper is too long - the light reflecting off the plate flickers as the angle changes (you're pressing down on one end of the plate at a time). Otherwise, the light reflecting off the pressure plate doesn't change and the caliper just stops at the mount. I found that the 'flickering reflected light' effect was quite obvious, even with depth changes of around 0.02mm.
Here's a photo of it with a recently-acquired silver J-8 fitted...
The focus index doesn't line up perfectly (possibly intentional design to allow the index to be seen past an add-on finder), but I'm happy with it as it is. The J-8 was bought with the intention of rehousing my pre-war f2 Sonnar (to get it out of the rotating-front black J-8 mount). However, the silver J-8 is in excellent condition - elements are spotless, and the mount is really clean - no grubbiness in the knurling, no pitting or corrosion. I didn't have to do anything to it other that re-grease the aperture ring - focus helical was already peachy. I felt it was too nice to become a bit of Sonnar mechanicals, so decided to keep it to pair with my J-12 on the FED.
I did some other things to the FED recently...
I had a look at the shutter tensioning, and found that the second curtain was rather slack. What led me to this was some earlier attempts to measure the lens registration. When measuring, the shutter is set to B and held open. One of the times when I released it, I noticed that the second curtain didn't go all the way across - it stopped 2 or 3mm short. This was repeatable, but intermittent. So I had a go at adjusting the tension (a fiddly job that I haven't tried before), and got what I felt was a better balance - a snappier feel, and the sluggishness hasn't returned. I suspect the slow 2nd curtain might explain the mysterious fogging I was getting at the edges of some frames, but will need to run a roll through it to be sure.
Before I started the lens mount change in earnest, I took the body shell off to see if something was amiss inside, that might explain the big discrepancy between the two sides. There was nothing obvious, other than a general feeling that the internal bits where the film runs are not particularly well made. I concluded that, if that's the path the film takes, then I'll just have to shim accordingly. I took the opportunity to look at the shutter in front of a CRT television, to hopefully get an idea of the curtain behaviour. The width of the gap seemed consistent from top to bottom, but I wondered if it was a bit wide - I got the feeling that 1/500 on the FED is similar to 1/250 on my M2. One day, I'll build a shutter speed tester that will give me proper numbers.
One other thing I did was adjust the long flat spring that the shutter release presses on. When I took this off, it had a noticable bow at the end near the two fixing screws. Some careful bending in the fingers had this mostly straightened, and the result was less force required to operate the shutter. It's still quite a bit heavier than my IIIf, but certainly better than it was.
Overall, the camera feels a bit more slick now. Next thing is to verify (or not) the recent work with a roll of film. I'll probably use a roll of Adox CHS 25, since it's quite fussy with exposure, and doesn't like over-exposure in particular. If the shutter speeds are running a bit slow, this might help to show this up. After that, I might look at rangefinder alignment - horizontal seems okay (it was fine with the original FED lens before the change of mount, and seems the same with the J-8 and J-12 after fitting the new mount). However, vertical is badly out.
Another thing that differs is the start of the M39 thread in the mount. If you fit a later lens, the focus and aperture index marks end up way out of position. You can turn the mount in 90-degree steps (the 4 screw holes are equispaced), but you'd then have to machine a recess in the new quadrant to ensure that the underside of the mount doesn't snag the rangefinder arm. To avoid machining the original lens mount, a mount for a later FED 2 was dontated to the cause by a pal.
While taking measurements to work out how much the new mount needed to be shimmed by, I noticed that the FED 2 mount is thinner than the FED 1 version, by about 0.3mm. This meant that, whatever measurements I took with the FED 1 mount in place, I'd have to add 0.3 to the thickness of the shimming. I also found that there was a pretty large discrepancy at each side of the mount. The higher side was where there was more paper shim (as originally fitted), so I took all of the shims out and fitted the FED 1 mount directly onto the metal of the body shell. The high side was still higher, but still low by about 0.35mm. The low side was about 0.3mm or so lower again.
So, to get the FED 2 mount to land at the correct registration, I needed a shim 0.65mm thick, with some extra shimming of about 0.3 at the low side. Rather than cut up bits of drinks cans (handy stuff - 0.1mm thick, and cuts easily with scissors), I elected to make one on the lathe - much easier to get a precise fit around the mount, and to control the thickness.
The photo below shows the camera with the mount removed, with the FED 2 mount and shim below. The paper shims are nearby - I cut the one that was originally circular in half, since I expected to need this on the low side. Note that the new shim has a bit cut out to clear the rangefinder arm. I found that I didn't need to remove any material from the FED 2 mount. There is also a sliver of drinks can in case I need it.
At first I tried it with two paper shims, but it was still too low. Then I tried with three shims, plus the sliver of drinks can (next to the paper shims), and this was too high. The three paper shims on their own seem to have got a pretty good balance - both sides are just about the same.
I haven't run any film through it yet, but setting the lens to infinity gets good alignment in the rangefinder. Measuring the registration is quite fiddly. I used a digital caliper and found that the easiest way is to set the depth thingy to a fixed amount, and move it down onto the pressure plate until the caliper stops at the lens mount. With a desk lamp shining in, you can see the pressure plate move a little if the depth on the caliper is too long - the light reflecting off the plate flickers as the angle changes (you're pressing down on one end of the plate at a time). Otherwise, the light reflecting off the pressure plate doesn't change and the caliper just stops at the mount. I found that the 'flickering reflected light' effect was quite obvious, even with depth changes of around 0.02mm.
Here's a photo of it with a recently-acquired silver J-8 fitted...
The focus index doesn't line up perfectly (possibly intentional design to allow the index to be seen past an add-on finder), but I'm happy with it as it is. The J-8 was bought with the intention of rehousing my pre-war f2 Sonnar (to get it out of the rotating-front black J-8 mount). However, the silver J-8 is in excellent condition - elements are spotless, and the mount is really clean - no grubbiness in the knurling, no pitting or corrosion. I didn't have to do anything to it other that re-grease the aperture ring - focus helical was already peachy. I felt it was too nice to become a bit of Sonnar mechanicals, so decided to keep it to pair with my J-12 on the FED.
I did some other things to the FED recently...
I had a look at the shutter tensioning, and found that the second curtain was rather slack. What led me to this was some earlier attempts to measure the lens registration. When measuring, the shutter is set to B and held open. One of the times when I released it, I noticed that the second curtain didn't go all the way across - it stopped 2 or 3mm short. This was repeatable, but intermittent. So I had a go at adjusting the tension (a fiddly job that I haven't tried before), and got what I felt was a better balance - a snappier feel, and the sluggishness hasn't returned. I suspect the slow 2nd curtain might explain the mysterious fogging I was getting at the edges of some frames, but will need to run a roll through it to be sure.
Before I started the lens mount change in earnest, I took the body shell off to see if something was amiss inside, that might explain the big discrepancy between the two sides. There was nothing obvious, other than a general feeling that the internal bits where the film runs are not particularly well made. I concluded that, if that's the path the film takes, then I'll just have to shim accordingly. I took the opportunity to look at the shutter in front of a CRT television, to hopefully get an idea of the curtain behaviour. The width of the gap seemed consistent from top to bottom, but I wondered if it was a bit wide - I got the feeling that 1/500 on the FED is similar to 1/250 on my M2. One day, I'll build a shutter speed tester that will give me proper numbers.
One other thing I did was adjust the long flat spring that the shutter release presses on. When I took this off, it had a noticable bow at the end near the two fixing screws. Some careful bending in the fingers had this mostly straightened, and the result was less force required to operate the shutter. It's still quite a bit heavier than my IIIf, but certainly better than it was.
Overall, the camera feels a bit more slick now. Next thing is to verify (or not) the recent work with a roll of film. I'll probably use a roll of Adox CHS 25, since it's quite fussy with exposure, and doesn't like over-exposure in particular. If the shutter speeds are running a bit slow, this might help to show this up. After that, I might look at rangefinder alignment - horizontal seems okay (it was fine with the original FED lens before the change of mount, and seems the same with the J-8 and J-12 after fitting the new mount). However, vertical is badly out.
