Making a Pentax Auto 110 Adapter with Aperture Control

[CD77]

I’ve just picked up a 24mm from eBay (for less than £10… bargain!) and was hoping to make a 110 to C mount adapter, does anyone have an details/dimensions/drawings for the 110 lens mount???

I use 3D CAD and a 3D printer every day at work so I can make something bespoke... I'm just missing the 110 mount detail.

Happy to share the design if successful!

 

[CD77]

Also, if anyone has a 110 camera, could you measure the distance from the flange to the diaphragm... I've got an idea for an iris mechanism but want to position it correctly in relation to the lens.

 

[barry]

Also, if anyone has a 110 camera, could you measure the distance from the flange to the diaphragm... I've got an idea for an iris mechanism but want to position it correctly in relation to the lens.

I have a couple, but not sure I have way to measure it accurately.

 

[pellicle]

Also, if anyone has a 110 camera, could you measure the distance from the flange to the diaphragm.

Mines in a different country from me at the moment or I would.

However I'd argue that as long as it clears the shutter in the m43 camera that it'll be fine.

The mount I have is basically an adapted c mount adapter and there is precious little space between the back of the mount and the shutter.
This may help

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[barry]

Iirc, @gnarlydog australia dissected a body to get the mount, perhaps he has a way to measure it.

 

[pellicle]

Also, .

Aperture Washer for Auto 110 Lenses - PentaxForums.com

 

[CD77]

I got the lens yesterday and have designed a 3D printed adapter to convert a c-mount adapter to take a PX110 lens.

I'll post some more pics later but this it on my e-pl3.

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[CD77]

I have a couple, but not sure I have way to measure it accurately.

An approximate distance measured with a ruler would be ok, to the nearest mm (or an estimated half mm) would suffice.

 

[pellicle]

I got the lens yesterday and have designed a 3D printed adapter to convert a c-mount adapter to take a PX110 lens.

Great job

 

[pellicle]

An approximate distance measured with a ruler would be ok, to the nearest mm (or an estimated half mm) would suffice.

Well no it won't.
With a 24mm focal length you'll find that tiny fractions of a mm will influence how well infinity on the lens mates up with infinity. Too short and it focuses past infinity which can be annoying for those who rely in the stop built into the lens and its marking. Too long and it can't get to infinity. This can be confirmed during focus by using the focus assist magnification.
For instance
in my view ...: RJ Camera FD adaptor

You can observe this by seeing how far the lens extends on the thread as you focus from infinity to say 10 meters.

With a 28mm lens on an adaptor I dialled in, it was

 

[barry]

An approximate distance measured with a ruler would be ok, to the nearest mm (or an estimated half mm) would suffice.

I don't think I have a ruler that'll fit in the mount opening, but I'll look again.

 

[CD77]

Well no it won't.
With a 24mm focal length you'll find that tiny fractions of a mm will influence how well infinity on the lens mates up with infinity. Too short and it focuses past infinity which can be annoying for those who rely in the stop built into the lens and its marking. Too long and it can't get to infinity. This can be confirmed during focus by using the focus assist magnification.
For instance
in my view ...: RJ Camera FD adaptor

You can observe this by seeing how far the lens extends on the thread as you focus from infinity to say 10 meters.

With a 28mm lens on an adaptor I dialled in, it was

I have infinity focus on the mount in the pic, working with the difference between the c-mount and PX110 flange distances (9.474mm).

The measurement I need is going from the flange to the diaphragm in a 110 camera, this should be less critical as if it is slightly out it will either make the aperture smaller or larger than it would be to the exact calculation. As it stands any measurement, however approximate, is more than I have at the moment!

I'll just be making a mod to the design I have now to incorporate different apertures so I am confident I'll have infinity focus on the new design, although I have a plan to adjust if I need to!

 

[CD77]

I don't think I have a ruler that'll fit in the mount opening, but I'll look again.

No worries... you could use a piece of paper or card, put the end on the diaphragm and mark at the flange with a pencil and then measure with a ruler when removed from the camera.

 

[pellicle]

..., although I have a plan to adjust if I need to!

Emery paper took off the microns needed for me

The addendum section of this post is pertinent

in my view ...: FD lens adapter on Panasonic G1

With my 50mm I felt it wasn't a problem, with my 28 the effect was more pronounced.

 

[CD77]

More pics!

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[pellicle]

More pics!

great!

so, how it it 'secured' to the mount? Just friction (no lock?)
what was your print material (sorry if I missed that point)

 

[barry]

No worries... you could use a piece of paper or card, put the end on the diaphragm and mark at the flange with a pencil and then measure with a ruler when removed from the camera.

I remembered I have a PDF of rulers which can be laser printed...

It's about 3mm. Pics coming...

 

[gnarlydog australia]

Emery paper took off the microns needed for me

The addendum section of this post is pertinent

in my view ...: FD lens adapter on Panasonic G1

With my 50mm I felt it wasn't a problem, with my 28 the effect was more pronounced.

sandpaper works for me too but I am too impatient to get perfect distance on the focusing ring by creating the perfect adapter/spacing.
So, I rather reset my lenses' helicoid which is rather easy and fast.
On the 24mm and 50mm there are tiny screws on the focus grip, on the 70mm the screws are under the rubber.
I undo those and reset my infinity. On the 70mm I even take out the second stop (post) for minimum focus distance and allow the helicoid to travel past the marking and reach a single "post" set for infinity.
I gain a little bit of helicoid travel that way which helps with the rather average distance on the 70mm.

 

[barry]

@CD77, here's some pics. These are of a 110 Super, not that it matters as the iris is the same.
I took more at a couple other angles, let me know if you'd need them.

So, it's about 3mm from the inside plate (just in front of the iris) to the mount flange.

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Note there is a tiny gap between the iris and the plate.

 

[pellicle]

So, I rather reset my lenses' helicoid which is rather easy and fast.
On the 24mm and 50mm there are tiny screws on the focus

On the FD lenses?