Author Topic: mft mount - c-mount cannot be unscrewed  (Read 251 times)

romandegiuli

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mft mount - c-mount cannot be unscrewed
« on: November 25, 2022, 10:09:01 AM »
Hi All,

anybody else having the same issue that the c-mount cannot be unscrewed? I tried everything possible and even built a small tool to move the ring clockwise and counter-clockwise, but no chance. I left the c-mount where it is and attached the mft-mount on top, not sure if this is recommended...

Appreciate any ideas and comments!

Thanks!
Roman

Nikon1

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Re: mft mount - c-mount cannot be unscrewed
« Reply #1 on: November 25, 2022, 11:43:08 AM »
The MFT Mount Should Work with the C-Mount Ring Still attached to the Camera; as long as you can Make sure the Lens Clears the Stainless C-Mount Ring and has nothing Protruding on the Rear.
 However, as there has been quite some Confusion with people not knowing the Difference between the Actual C-Mount Ring that is Part of the Camera itself, and the 5mm C-Mount to CS-Mount Spacer Ring / Adapter that is screwed into it; it is generally Highly Recommended to remove the C-Mount Prior to using the MFT-Mount to avoid any Risk of Damage on Lenses or the Camera. Also Some Lenses and particularly Metabones Speedboosters and Similar Adapters have large Rear Elements that protrude quite a bit into the Camera and would hit that Ring.
 General Rule of Thumb: If you have to ask if you have to Remove the C-Mount Ring or Why, you should remove it (no offense, but thats kinda how it is...). Only leave it where it is, if you know exactly why you do so, else just remove it.
 .
 As far as removing the Ring, have you unscrewed the Small Screw on the Bottom of the Camera and removed it and the Small Brass Rod?
 See: https://forum.krontech.ca/index.php?topic=614.msg3949#msg3949
 That Screw is Meant to Hold Said C-Mount Ring in Place, so you dont accidentally have it Falling out, or have the Backfocus Change (as Screwing that Ring in or Out of the Camera further also determines the Proper Backfocus of your Lenses). That Screw Usually does a Extremely good Job at Preventing accidental Unscrewing of the Mount Ring, as well as Intentional Unscrewing Attempts.
 .
 I Personally Put a Small black Sharpie Mark where the White Line on the Camera Body is, so i can Just line these Two back up again, if i want to put it Back and save myself some Lengthy Backfocus Setting each time i do so.
« Last Edit: November 25, 2022, 11:52:19 AM by Nikon1 »

romandegiuli

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Re: mft mount - c-mount cannot be unscrewed
« Reply #2 on: November 30, 2022, 12:25:59 AM »
Thanks for getting back to me, totally agree the c-Mount should be removed and this was the first thing we wanted to do before attaching the mft-mount. We followed the instruction exactly, removing the screw and brass rod. This is pretty straight forward, however the c-mount does not move at all and we cannot use more force because we might slip and damage the sensor. Should we ship our camera for maintenance to you?

Thanks again,
Roman


Nikon1

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Re: mft mount - c-mount cannot be unscrewed
« Reply #3 on: November 30, 2022, 05:53:46 AM »
Can you post a Few Images of the Mount that is Stuck on the Camera, as well as Closeups of the Rod and Small Screw, ideally also from the Hole which the Screw and Rod originally where in?
 .
 Unless something is somehow Damaged Mechanically, its really somewhat Strange that it is not possible to unscrew the Ring.

ivandan

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Re: mft mount - c-mount cannot be unscrewed
« Reply #4 on: December 03, 2022, 07:10:51 AM »
There is another problem - if I remove this screw and rod - there will be a hole where the dust will fly.

Nikon1

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Re: mft mount - c-mount cannot be unscrewed
« Reply #5 on: December 03, 2022, 07:36:16 AM »
There is another problem - if I remove this screw and rod - there will be a hole where the dust will fly.
I did in fact inform Krontech, that i Think this is or Could be an Issue, at least in Theory.
 However, since i pretty much always run my Chronos with a rather Big Quick-Mount Plate Screwed onto the Bottom (which basically Completely Covers said Hole) and am Usually not in absurdly Dusty Places, i never did anything more about it than telling them.
 If that is a Problem for You, cause you run the Camera in Places where there is a lot of dust (Which i wouldnt doubt from that Red Bull Shot i seen), especially if your Rig or Mounting Solution does not Cover it on its own, ESPECIALLY if the Camera is used a lot inverted, meaning that Hole would be Facing upwards, then there is Basically 3 Solutions i did Consider (cant Remember, probably also wrote them to Krontech)
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 1. Pretty Temporary Solution, but just Tape It shut on the Outside.
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 2. Cut yourself a Little Wedge from some EVA Foam or something Similar, in a Shape that you can Push it into the Hole to cover it, and it not getting Loose on its own, but with just enough Material Left still sticking out, so you can still grab onto it and remove it Later with some tweezers or something.
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 3. Machine or get machined a custom Cover Screw. This is the most Professional, most Proper and most Long-Term Solution, but also Requires far more Effort. I considered Making one for myself, but never had much Problems with dust anyways, as that Hole on mine was Basically covered, so i did never actually go on to make one. If you are Interested, i can look into it again, and Either provide you with Blueprints / Dimensional Drawings, so you could get one Machined Locally, or just make it myself and Send it to you. As its just a tiny Size Part, that could very easily be Shipped as a Small Letter Envelope. but if i recall Correctly, you where from Russia, and i am absolutely not up-to-Date with whatever Stupid Restrictions on Shipping stuff to Russia from Germany are there Currently, but willing to try and send one anyways, if you want.
 Otherwise, if there are Restrictions still, you will easily find someone with a Lathe able to make a Cover Screw with some Dimensional Drawings. Doesnt need to be Crazy Precise of a Part, as its literally just a Screw-in-Plug, but its Fairly Tiny, so could be Challenging on the Kind of big Lathe and Tooling i imagine some average Local Shop in Russia would have?  .
 If i can Provide any Help with option 3, either making one or Drawings, let me know.