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Explore the world of vintage lenses through repair notes, real test shots, and detailed archive threads packed with images.

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C Mount adapter issue
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Hi folks

With both my G3 and GF3 I am having an issue where c mount adapters won't work - it gives me a black screen and I can't take a picture, but as soon as I remove the adapter from the camera, it works again.

Seems to me that the adapter is pushing down the electrical pins in the bottom half of the camera and due to this the camera won't function properly.

So is there a workaround for this? Am I going to have to get the Dremel out and grind a trough into the adapter so it clears the pins?


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Ian, check the hole for the lock pin. The lock pin has to fully release .
Sometimes on c mount adapters the hole isn't deep enough or shaped wrong.


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The hole in this one is all the way through. The issue starts before you've even rotated the lens at all to lock it.


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A piece of electrical tape (or layer of paint) on adapter to insulate?


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iangreenhalgh1 wrote:
The hole in this one is all the way through. The issue starts before you've even rotated the lens at all to lock it.


What issue? Do you feel abnormal dragging?

If you mount an adapter and lens with the camera on, the screen wont show an image until the adapter locks.
You will only get an image if the lock pin on the camera fully releases.
If the hole on the adapter is missdrilled it binds the pin.

Please post a pic of both sides of the adapter.


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No, you always get an image, even when there is no lens on the camera and the pin isn't depressed. It is when the adapter touches the electrical pins that the image cuts out.

I'll make a little video showing what's happening.


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visualopsins wrote:
A piece of electrical tape (or layer of paint) on adapter to insulate?


I can certainly try that, good idea!


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walter g wrote:

If you mount an adapter and lens with the camera on, the screen wont show an image until the adapter locks.
You will only get an image if the lock pin on the camera fully releases.
If the hole on the adapter is missdrilled it binds the pin.


Yes, my guess is that this is what is happening. I have had this on a few adapters.

iangreenhalgh1 wrote:
No, you always get an image, even when there is no lens on the camera and the pin isn't depressed.


Exactly. the lock pin must not be in any way depressed (even by a small amount) for the image to show. So when you put the adapter on, but the lock pin doesn't extend fully into the notch, the image does not show.


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I`ve had this issue to, and it was the pin Wink


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Hmm, I'm confused, the adapter has a hole all the way through for the pin and you don't get an image if the pin is in that hole or not - being a hole all the way through, you can see if the pin is engaged or not.

I was going to make a video but a neighbour had a fire in her kitchen so I ended up helping her out all day instead.

Hopefully tomorrow.

Thanks for the help.


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Well, it works now. It was that damn pin. The adapter wasn't blocking it but the pin itself was somewhat sticky in it's movement. Wiggling it a bit seems to have freed it up and all is now fine.

Thanks for the help guys, much appreciated.

Fujinon-TV 1.4/50:



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Slightly off topic, but I've tried two different adapters with my Fujinon TV 1/4 50.
The thin adapter I get 6 feet maximum focus distance at f1.4.
The adapter with the rim I get 10 feet at f1.4.


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walter g wrote:
Slightly off topic, but I've tried two different adapters with my Fujinon TV 1/4 50.
The thin adapter I get 6 feet maximum focus distance at f1.4.
The adapter with the rim I get 10 feet at f1.4.


shim to make adapter thicker


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visualopsins wrote:
walter g wrote:
Slightly off topic, but I've tried two different adapters with my Fujinon TV 1/4 50.
The thin adapter I get 6 feet maximum focus distance at f1.4.
The adapter with the rim I get 10 feet at f1.4.


shim to make adapter thicker


That would make things worse (reduce maximum focus distance).

I machined the back of my Fujinon to get infinity focus.

Mark


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SXR_Mark wrote:
visualopsins wrote:
walter g wrote:
Slightly off topic, but I've tried two different adapters with my Fujinon TV 1/4 50.
The thin adapter I get 6 feet maximum focus distance at f1.4.
The adapter with the rim I get 10 feet at f1.4.


shim to make adapter thicker


That would make things worse (reduce maximum focus distance).

I machined the back of my Fujinon to get infinity focus.

Mark


Oops! I was wrong...



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SXR_Mark wrote:
visualopsins wrote:
walter g wrote:
Slightly off topic, but I've tried two different adapters with my Fujinon TV 1/4 50.
The thin adapter I get 6 feet maximum focus distance at f1.4.
The adapter with the rim I get 10 feet at f1.4.


shim to make adapter thicker


That would make things worse (reduce maximum focus distance).

I machined the back of my Fujinon to get infinity focus.

Mark


The other option is to unscrew the rear ring that holds the mount on, and glue the mount on.
Not sure which im going to do.