How can I mount a focusing rail to make it more stable?

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trobinson41
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Joined: Sun Oct 23, 2022 8:28 am
Location: La Mesa, CA, US

How can I mount a focusing rail to make it more stable?

Post by trobinson41 »

I have a bellows mounted on a NiSi macro focusing rail (model NM-180). The setup is ridiculously top-heavy and unstable. I need to mount it on something to make it stable. It does attach to a tripod, although it's way too wobbly. Maybe I need a more robust (aka expensive) tripod? Mostly, though, I want to mount it on a board or something that I can sit on a table. Any suggestions? Thanks!
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Pau
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Re: How can I mount a focusing rail to make it more stable?

Post by Pau »

At the following video you have a good review and some ideas on how to improve it
https://www.youtube.com/watch?v=HxA-h4zLYRA

In the field a sturdy enough tripod would be desirable but for high magnification at the studio attaching it to a plate seems a much better option. Being its lower part Arca Swiss compatible this would be straightforward
Pau

trobinson41
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Joined: Sun Oct 23, 2022 8:28 am
Location: La Mesa, CA, US

Re: How can I mount a focusing rail to make it more stable?

Post by trobinson41 »

Awesome! Thanks, Pau!

BarryR
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Joined: Sat Feb 04, 2023 8:22 am
Location: South Carolina

Re: How can I mount a focusing rail to make it more stable?

Post by BarryR »

For starters I would take the legs off the rail !!! (But Im new here !!) :D

enricosavazzi
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Re: How can I mount a focusing rail to make it more stable?

Post by enricosavazzi »

If you are equipped to make some mechanical modifications involving drilling and tapping, there are additional improvements to consider.

One is that the lowermost slider and rack of the Nikon bellows are no longer necessary if you mount the bellows on a separate focusing rail. The nylon inserts of the slider are slightly elastic, and the slider must be locked really hard (which increases wear of the parts) to prevent the bellows creeping within the slider when mounted vertically or at a high angle. This also requires removing the geared rack at the bottom of the prismatic bar of the belllows, and drilling and tapping two holes (preferably 1/4-20) there, to allow attaching a long Arca-compatible plate as a replacement for the slider. You can see the modified bellows in post n. 8 at http://www.photomacrography.net/forum/v ... =8&t=45632 .

Perhaps in your case it would be even better to skip the Arca plate at the bottom of the bellows and directly attach the prismatic bar of the bellows to the top platform of the focusing rail, to get an even lower distance between the base of the focusing rail and the lens axis.
--ES

colohank
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Location: Fruita, Colorado, USA

Re: How can I mount a focusing rail to make it more stable?

Post by colohank »

You've gotten some good advice. Let me add that the adjustments on your manual focusing rail are probably too coarse for use with the 10X microscope objective shown in your setup. If your focusing rail is similar to my SunwayFoto MFR-150S, then one turn of the lead-screw will move the carriage 1.25mm. I can estimate 1/8th turns pretty reliably on mine (the knob isn't calibrated), but a 1/8th turn still moves the carriage 5/32 mm, or a bit more than 156 microns. Depth of focus at 10X is vanishingly small. Even if you could estimate 1/16th turns of the knob, a 78-micron increment between focus steps at 10X is excessive.

A manual rail is better suited to much lower magnifications.

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