Vickko
Veteran
Twice in 10 years - I realigned the helix of a 50/1.1 External Mount Nikon last night.
The first time was when I bought a NOS lens from a store in Montreal. I shot with it and had a heart attack when the photos were out of focus. After some careful experimentation, I hypothesized that the focus helix was "one thread off". I disassembed the lens and got it back together properly.
Recently, I received another 50/1.1 external mount that obviously was reassembled incorrectly. But it was very stressful doing the repair, because I had forgotten some of the finer details. I do remember the larger details, like the horrifying "click" that happens when you undo a couple screws, and hear something fall off inside the lens.
But, after puzzling over it for a few hours in the evening, I got the lens back together and tested properly with my M9 and Amedeo M to S adapter.
In case you want to try this yourself, here are my notes:
Nikon 5cm f1.1 focus helix disassembly
==============================
0. turn the lens to infinity and mark the axial locations of the lens ring edges
1. remove the rear cover plate (2 screws)
1a. do NOT remove the two screws that hold the slot slider bar. There is no need to take it off, and it must be assembled when putting the helix back together.
2. turn the lens to infinity
3. two screw heads will be visible through the cover plate. Remove them. This holds the focus rotation block. This block also holds the rear focus transfer ring, and spring.
4. unscrew the lens head, unscrewing the focus ring and making a note of where it disengages. Note both the focus scale and the lens head for where it disengages. The lens head is on a multiple thread helix. Note carefully where it disengages. When the screw head comes off, the rear
focus position ring, and its spring, will come off.
5. The focus ring can be further disassembled. It is on a left hand thread. Do not remove the focus scale ring, as it can help align the
scale when putting it back together.
6. if you do take the focus ring off, be very careful with the grub screws. They are tiny and have the ability to invisibly cloak themselves.
=============
Re-assembly hints.
1. for the focus position transfer ring, put it back together, positionng the slot and over the rider pin. Do not insert the spring. The
spring can be installed after the lens head is re-assembled.
2. install the focus scale ring first, turning it to the correct location.
3. engage the head at the correct helix start.
4. turn the lens to infinity.
5. Now locate the rotation stop. It can be rotated using the focus position transfer ring.
6. to install the screws, hold the lens upright and wedge the screw into a tight fit screwdriver. Insert the screws vertically into the hole.
If the screw falls off, the helix must be taken apart to remove the screw.
..... the end.
The first time was when I bought a NOS lens from a store in Montreal. I shot with it and had a heart attack when the photos were out of focus. After some careful experimentation, I hypothesized that the focus helix was "one thread off". I disassembed the lens and got it back together properly.
Recently, I received another 50/1.1 external mount that obviously was reassembled incorrectly. But it was very stressful doing the repair, because I had forgotten some of the finer details. I do remember the larger details, like the horrifying "click" that happens when you undo a couple screws, and hear something fall off inside the lens.
But, after puzzling over it for a few hours in the evening, I got the lens back together and tested properly with my M9 and Amedeo M to S adapter.
In case you want to try this yourself, here are my notes:
Nikon 5cm f1.1 focus helix disassembly
==============================
0. turn the lens to infinity and mark the axial locations of the lens ring edges
1. remove the rear cover plate (2 screws)
1a. do NOT remove the two screws that hold the slot slider bar. There is no need to take it off, and it must be assembled when putting the helix back together.
2. turn the lens to infinity
3. two screw heads will be visible through the cover plate. Remove them. This holds the focus rotation block. This block also holds the rear focus transfer ring, and spring.
4. unscrew the lens head, unscrewing the focus ring and making a note of where it disengages. Note both the focus scale and the lens head for where it disengages. The lens head is on a multiple thread helix. Note carefully where it disengages. When the screw head comes off, the rear
focus position ring, and its spring, will come off.
5. The focus ring can be further disassembled. It is on a left hand thread. Do not remove the focus scale ring, as it can help align the
scale when putting it back together.
6. if you do take the focus ring off, be very careful with the grub screws. They are tiny and have the ability to invisibly cloak themselves.
=============
Re-assembly hints.
1. for the focus position transfer ring, put it back together, positionng the slot and over the rider pin. Do not insert the spring. The
spring can be installed after the lens head is re-assembled.
2. install the focus scale ring first, turning it to the correct location.
3. engage the head at the correct helix start.
4. turn the lens to infinity.
5. Now locate the rotation stop. It can be rotated using the focus position transfer ring.
6. to install the screws, hold the lens upright and wedge the screw into a tight fit screwdriver. Insert the screws vertically into the hole.
If the screw falls off, the helix must be taken apart to remove the screw.
..... the end.
