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WARNINGS
- This modification requires the dis-assembly of the lens mount ring from your Nikon F mount lens and will require the user to have some experience in lens dis-assembly/assembly.
- Always proceed with caution.
- After modification, the lens will lose infinity focus when mounted on Nikon F mount film cameras/DSLR.
- Modification is reversible.
Effects of modifications
The modified lens will have the following results:
1. Achieve infinity closer to the infinity mark indicated on the lens when mounted on PK+MM installed DSLRs.
2. Achieve larger clearance from PK+MM mount ring during mounting (applicable for lenses with tab on aperture ring)
3. Lens will lose infinity focus when mounted on Nikon F mount film cameras/DSLR.
Modification summary and background information
This modification involves putting 0.9mm thick nylon washers behind the Nikon F lens’ lens mount so that the main lens body/barrel is now 0.9mm further away from the PK+MM mount ring. This gives the lens more mounting clearance and in effect, almost correcting the focusing past infinity inconvenience Nikon F mount(ffd:46.50mm) lenses face when mounted on PK+MM due to its 1.04mm longer flange focus distance (ffd) difference from Pentax K(ffd:45.46mm). The resultant ffd of the modified lens is now 45.60mm.
- This modification requires the dis-assembly of the lens mount ring from your Nikon F mount lens and will require the user to have some experience in lens dis-assembly/assembly.
- Always proceed with caution.
- After modification, the lens will lose infinity focus when mounted on Nikon F mount film cameras/DSLR.
- Modification is reversible.
Effects of modifications
The modified lens will have the following results:
1. Achieve infinity closer to the infinity mark indicated on the lens when mounted on PK+MM installed DSLRs.
2. Achieve larger clearance from PK+MM mount ring during mounting (applicable for lenses with tab on aperture ring)
3. Lens will lose infinity focus when mounted on Nikon F mount film cameras/DSLR.
Modification summary and background information
This modification involves putting 0.9mm thick nylon washers behind the Nikon F lens’ lens mount so that the main lens body/barrel is now 0.9mm further away from the PK+MM mount ring. This gives the lens more mounting clearance and in effect, almost correcting the focusing past infinity inconvenience Nikon F mount(ffd:46.50mm) lenses face when mounted on PK+MM due to its 1.04mm longer flange focus distance (ffd) difference from Pentax K(ffd:45.46mm). The resultant ffd of the modified lens is now 45.60mm.
Required items:
1. A Nikon F mount lens for modification.
2. Screw driver (compatible with the screws on the Nikon F lens’ lens mount)
3. 0.9mm thick nylon washers, recommended size M2.5 (internal hole 2.5mm, external size 5mm and thickness 0.9mm) . Quantity should be the same as the number of screws on Nikon F lens mount. These washers can be bought from your local hardware store or online e.g Ebay.
4. A sharp craft knife, scissors or nail-clipper (to trim the sides of the washer)
1. A Nikon F mount lens for modification.
2. Screw driver (compatible with the screws on the Nikon F lens’ lens mount)
3. 0.9mm thick nylon washers, recommended size M2.5 (internal hole 2.5mm, external size 5mm and thickness 0.9mm) . Quantity should be the same as the number of screws on Nikon F lens mount. These washers can be bought from your local hardware store or online e.g Ebay.
4. A sharp craft knife, scissors or nail-clipper (to trim the sides of the washer)
Procedure:
1. Trim the washer by approximately 1mm at each opposite sides as shown. This is to allow the washer to fit into the small space in-between screw and mount ring inside the lens.
1. Trim the washer by approximately 1mm at each opposite sides as shown. This is to allow the washer to fit into the small space in-between screw and mount ring inside the lens.
2. Unscrew all the screws on the lens mount ring from the Nikon F mount lens.
3. Slowly lift if away from the lens barrel/body.
4. Check that the trimmed washer can fit into (1) the screw and (2) the small space in-between screw and mount ring
5. Carefully place the trimmed washers at each of the location of the screw holes on the lens barrel/body side.
3. Slowly lift if away from the lens barrel/body.
4. Check that the trimmed washer can fit into (1) the screw and (2) the small space in-between screw and mount ring
5. Carefully place the trimmed washers at each of the location of the screw holes on the lens barrel/body side.
6. Assemble the mount ring onto the lens barrel/body slowly, ensuring that the washers remain at its position.
7. Screw back all the screws tight, ensuring all of them pass through its respective washer. Do not over tighten.
8. Modification is completed. You can reverse this modification by repeating the same steps and removing the washers under Step 5.
Credits:
The source of this idea came from our ingenious PK+MM user Noel Parsons when he informed us that he used this modification to get his Nikon Pre AI 105mm F2.5 lens to mount on his K-01.
7. Screw back all the screws tight, ensuring all of them pass through its respective washer. Do not over tighten.
8. Modification is completed. You can reverse this modification by repeating the same steps and removing the washers under Step 5.
Credits:
The source of this idea came from our ingenious PK+MM user Noel Parsons when he informed us that he used this modification to get his Nikon Pre AI 105mm F2.5 lens to mount on his K-01.
