Nikon SMZ-U alignment of zoom field of view centre

[Nicksmith]

Hi there, need some advice...

I have a Nikon SMZ-U which seems to function OK however the "axis of zoom" is offset about a 5th off from the centre of the eyepiece field of view, closer to 12 o'clock position, instead of being dead centre. To put it another way, if I zoom in on a speck dead centre in the eyepiece field from low power to around 70x, the speck is out of the FOV by the time I hit maximum. Hopefully my description makes sense.

The ED Plan 1.0x objective has a small ding on the rim due to packing error (it was packed attached), and I cannot unscrew it by hand (I have not tried a strap wrench yet). It seems collimated as I can see an airy disc with clear second diffraction ring around the outside on small bright objects, and the prisms are both collimated - I checked for rotation in each eyepiece.

Chromatic aberration is reasonably well controlled and the objective looks robustly made though there are no visible collimation screws on the outside of the casing. I would have expected worse performance if the objective misaligned but have no experience with this type of microscope to confirm, and it may be the design is just very tolerant of misalignment.

Maybe this is normal, but it seems to me that the objective must be tilted slightly, relative to the zoom lens assembly, or at least I can't think of another explanation...?

Any CMO stereo users or techs out there who know if this is normal, or a problem and how to fix it?

Cheers, Nick

[abednego1995]

Hi, has the problem resolved?
From experience tearing down a few SMZ-U's in the past, you're probably having a problem with collimation.
Not sure if it's from shock damage, or tampering, but it's repairable.

You have to strip the outer casing and access the zoom mechanism inside. You'll find 2 sets of lenses that converge and diverge with zooming function.
The lower set has collimation adjustment screws (I remember them as tiny hex grub screws on with red locktite) located at 3 and 6 o'clock
positions, so try releasing the locktite first and under maximum magnification try adjusting them. They're in a spring mount, so don't try to remove the assembly from
the carriage. That would end up in more problems than answers.

Hope it works.

John

EDIT
So sorry, I've misunderstood the problem. If both right and left views through the oculars match this isn't a body collimation problem.
Other possibilities could be a displacement of the binocular head relative to the body. But you've probably already tried removing it and retightening the retainer screw on the front...
Worse possibilities would be a displacement of the roof prism in the head, or even worse, the objective mount cracked (It's aluminum or magnesium diecast underneath, though unlikely...is a possibility)
If all persists.. adjusting both aforementioned left and right adjustment collimation screws at the 6 o'clock position might help, since this will only cause vertical image shift.

[Scarodactyl]

My guess is misalignment of the head if you haven't checked that already. I've had that happen while swapping heads between my dad's smz-10 and my scienscope smz clone, and it can be surprisingly convincing from the outside until you get it seated correctly.

[Nicksmith]

Thanks Guys I'm going to check this out, I only checked the binocular head by widening the eyepiece holders and checking for image shift - there was none I could see. How do I correct for misalignment of the head if it's seated correctly? I hadn't thought of that...

best Nick

[Nicksmith]

Hi Guys just to say this is resolved the and scope is now performing just great - it was the binocular head unit after all - alignment so I was send another head unit and it's bang-on!

[abednego1995]

Congrats! Good to hear it has resolved