Leitax Nikkor to Pentax K mount instructions

This is my manual Nikkor 50/1.8

We cannot use the Leitax mount on newer lenses with CPU contacts.

Most of the lenses made by Nikon have the screw holes at the standard positions, but not all. Please check it before ordering the Leitax mount.

Also, to make sure if the Nikon lens can use the Leitax mount for Pentax cameras, we have to know if the lens can operate the aperture ring without its own mount.

First, let's remove the original mount.

And try to open and close the iris rotating the aperture ring, but without the mount.

Here two different Nikkor mounts, the one at the left (50/1.8) is not needed for the aperture ring to operate the iris.

The one at the right (20/2.8) is necessary for the iris operation, so this second lens cannot be converted to Pentax.

In case the lens is compatible. We can start the conversion lifting the aperture ring.

We have to measure the thickness of the aperture ring at the part where the two levers are.

To avoid collision with the Pentax camera mount, we have to sand down 0.2 mm there.

We need a sheet of fine sand paper.

Work slowly and check the thickness frequently on the sides and center of the big lever, correcting when the measures are not even.

Depending where you press with the finger on top of the ring, you can control the point where there is more abrasion.

Now the other lever.

Caution! it is very small and it will be ready faster than you expect.

We have reduced the thickness 0.2 mm on both levers.

After sanding down the levers, we have to clean the aperture ring from the debris and install it on the lens again.

Now, take the Leitax mount and put the red dot at the top position of the lens.

And make coincide the holes of the lens and mount.

We are going to use the provided screws.

Please tell me if your lens original screws are longer than the standard  3-4 mm, so I will include the correct length ones.

Here you can see than the lever is now not colliding with the Pentax camera mount.

And you can use the Nikon lens.

But, what if  we want to use this modified lens later on a Nikon camera ?

No problem, the levers have still plenty of  thickness to couple with a Nikon camera.

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