Nickfed
Well-known
A bit of a confidence boost..........
This only addresses the focussing helix.
The best source is well-known enuff
http://pentax-manuals.com/repairs/j8service.pdf
but I refer particularly to the black versions. Contrary to rumour, I'm sure the black ones are serviced exactly as the silver "Lens 1" described above.
The most worrying thing is getting the lens unit out of the focus unit. It will come out - trust me. Grip the whole front, and by that I mean the aperture ring and the front ring with the filter thread. Do it as one, take a deep breath and twist...
The rest is easy, but make sure you have a quality screwdriver of the right size to undo the grub screws.
Both the focussing ring and the dress ring with the DoF scale have three grub screws. None of them need to come right out. Having the screw slots proud is about as far as you need to go. The dress ring has more meat in it than you would think.
The four-start helix unit takes a little less than 1 1/2 turns to come out. The stop screw in this can be used as a pointer, i.e. about 180 from the hole whence the screw indicated by the yellow arrow was removed.
I made a mark on the outer ring to show where the screw at the right end of the DoF scale should go. The big screw on the helix can be used as a pointer and then you can set the dress ring screws by feel. The focus ring is set by simply screwing the helix down, aligning the infinity mark, and setting those screws by feel too.
When greasing, be quite frugal and ensure that no grease is clearly visible when the gear is assembled. Even if you can't see it, you can be sure there is enough there simply by feel. For previous lens jobs I used a high quality silicon grease from the American Grease Stick company. I wouldn't have anything else for the aperture ring but I think it's a bit light for the helix. This time I used a standard automotive lithium grease just like you would shoot into the universal joints in the good old days. You can do this secure in the knowledge that you can always change it.
Be assured, you only have to do this once, and it will always be easy to do it again.
This only addresses the focussing helix.
The best source is well-known enuff
http://pentax-manuals.com/repairs/j8service.pdf
but I refer particularly to the black versions. Contrary to rumour, I'm sure the black ones are serviced exactly as the silver "Lens 1" described above.
The most worrying thing is getting the lens unit out of the focus unit. It will come out - trust me. Grip the whole front, and by that I mean the aperture ring and the front ring with the filter thread. Do it as one, take a deep breath and twist...
The rest is easy, but make sure you have a quality screwdriver of the right size to undo the grub screws.
Both the focussing ring and the dress ring with the DoF scale have three grub screws. None of them need to come right out. Having the screw slots proud is about as far as you need to go. The dress ring has more meat in it than you would think.
The four-start helix unit takes a little less than 1 1/2 turns to come out. The stop screw in this can be used as a pointer, i.e. about 180 from the hole whence the screw indicated by the yellow arrow was removed.
I made a mark on the outer ring to show where the screw at the right end of the DoF scale should go. The big screw on the helix can be used as a pointer and then you can set the dress ring screws by feel. The focus ring is set by simply screwing the helix down, aligning the infinity mark, and setting those screws by feel too.
When greasing, be quite frugal and ensure that no grease is clearly visible when the gear is assembled. Even if you can't see it, you can be sure there is enough there simply by feel. For previous lens jobs I used a high quality silicon grease from the American Grease Stick company. I wouldn't have anything else for the aperture ring but I think it's a bit light for the helix. This time I used a standard automotive lithium grease just like you would shoot into the universal joints in the good old days. You can do this secure in the knowledge that you can always change it.
Be assured, you only have to do this once, and it will always be easy to do it again.