Nikon stage focus motor? seeking information

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blekenbleu
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Nikon stage focus motor? seeking information

#1 Post by blekenbleu » Thu Aug 18, 2022 6:15 pm

My Metaphot has a motor attached to its stage focus:
Image

I seem to recall having seen it on other Nikon frames and suppose that it may have been a Nikon option,
but have yet to stumble over any documentation about it,
perhaps because I do not know what words Nikon may have used to describe it.

Any information about it, and particularly its controller, would be appreciated!
Metaphot, Optiphot 1, 66; AO 10, 120, EPIStar, Cycloptic

PeteM
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Re: Nikon stage focus motor? seeking information

#2 Post by PeteM » Thu Aug 18, 2022 7:30 pm

That might be a third party stepper??

The one I have is called the Nikon "Remote Focus Accessory" and fits the Labophot-Optiphot-Microphot-Metaphot etc.: http://www.mvi-inc.com/wp-content/uploa ... 99888-.pdf

It allows very fine increments for focus stacking - and someone with more skill or patience than I might figure out how to automate the whole process of focus-trigger camera-settle-focus . . . for whatever steps and number of images were wanted. The serial port commands are pretty well documented.

From your other posts, it sounds like you might have enough electronics background to figure out your own controller if the motor in yours is labeled -- and you can't find a used controller for your version. For most of us, one of the newer steppers complete with a controller might be the easy way out? Probably some reports and reviews on those over at the photomacrography forum.

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Re: Nikon stage focus motor? seeking information

#3 Post by blekenbleu » Thu Aug 18, 2022 8:21 pm

PeteM wrote:
Thu Aug 18, 2022 7:30 pm
That might be a third party stepper??
Certainly possible, or perhaps a predecessor to their "Remote Focus Accessory"...?
Perhaps I saw one on some old semicustom wafer inspection rig using Nikon optics.
The serial port commands are pretty well documented.
I suspect that this may be only a stepper motor with no logic.
From your other posts, it sounds like you might have enough electronics background
.. but also old enough to hope someone has already solved this.
For most of us, one of the newer steppers complete with a controller might be the easy way out?
Lacking access to 3D printing or milling machine, I already have a WeMacro rail
https://blekenbleu.github.io/microscope/stacking
and may end up hacking an interface between the WeMacro controller and this motor,
if I can sort its power and timing requirements (and it's not fried).

Thanks!
Metaphot, Optiphot 1, 66; AO 10, 120, EPIStar, Cycloptic

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Re: Nikon stage focus motor? seeking information

#4 Post by blekenbleu » Tue Aug 23, 2022 7:17 pm

PeteM wrote:
Thu Aug 18, 2022 7:30 pm
That might be a third party stepper??
Bingo! Third party == ITP.
I found another, less arm/vertical illuminator: https://www.ebay.com/itm/224886967771
ITP.jpg
ITP.jpg (79.56 KiB) Viewed 2739 times
Metaphot, Optiphot 1, 66; AO 10, 120, EPIStar, Cycloptic

PeteM
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Re: Nikon stage focus motor? seeking information

#5 Post by PeteM » Tue Aug 23, 2022 10:07 pm

No idea if it would work -- and the price seems very high (recollection was something like $399) -- but a Nikon remote focus controller showed up on Ebay a bit ago. I suspect it will go unsold - maybe subject to an offer at some point.

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Re: Nikon stage focus motor? seeking information

#6 Post by blekenbleu » Wed Aug 24, 2022 11:19 am

Focus motor is only 2-wire:
Image
.. presumably DC and just a power assist, rather than a focus stepper.
The wire to it twists and untwists during stage height changes.
Provision for easy removal is unobvious;
the motor mount appears to be cemented to a stock Nikon coarse focus knob.
Metaphot, Optiphot 1, 66; AO 10, 120, EPIStar, Cycloptic

PeteM
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Re: Nikon stage focus motor? seeking information

#7 Post by PeteM » Wed Aug 24, 2022 8:26 pm

Should you want a replacement Nikon focus knob, I likely have one you could have. Or, perhaps the motor is geared down low enough to still be useful?

At least you won't have a controller to find or build . . .

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Re: Nikon stage focus motor? seeking information

#8 Post by blekenbleu » Wed Aug 24, 2022 9:40 pm

PeteM wrote:
Wed Aug 24, 2022 8:26 pm
At least you won't have a controller to find or build . . .
I have yet to sort what power that motor wants,
then supply it controlled by something like 1 axis of an analog joystick.
Focus gearing seems fairly fine, but wants testing, after:
- connectors arrive for AC and lamp power
- Metaphot base electronics are resuscitated
- lamps (12V 100W) arrive
- a condenser carrier is improvised

In theory, even if not precise steps, brief nudges of PWM power to that (DC) motor
might move the stage in increments small enough for focus stacking...
Metaphot, Optiphot 1, 66; AO 10, 120, EPIStar, Cycloptic

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Re: Nikon stage focus motor? seeking information

#9 Post by blekenbleu » Wed Aug 24, 2022 9:49 pm

PeteM wrote:
Wed Aug 24, 2022 8:26 pm
a replacement Nikon focus knob
About that - at least on an Optiphot 66,
large focus knobs thread on a brass tube, inside which the fine focus rod rotates.
Tube threads for those large knobs are cemented in place by Nikon,
having been adjusted to provide appropriate drag of some grease against a polymer washer.
What compound is appropriate for re-locking knob threads?
Metaphot, Optiphot 1, 66; AO 10, 120, EPIStar, Cycloptic

PeteM
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Re: Nikon stage focus motor? seeking information

#10 Post by PeteM » Wed Aug 24, 2022 10:04 pm

My guess would be something like a purple (low strength) "Loctite" thread locker. It should secure the knob, but be removable with a bit more torque. Next up would be blue Loctite - significant torque needed. Not suitable IMO: green Loctite (needs heat to remove -- and hard to do with those knobs), followed by red (more or less permanent unless significant heat and torque).

Threads need to be clean before application.

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