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11-28-2007, 04:08 PM   #1
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"Bayonet" mount question...

I just bought a K mount Kiron 1.5x Match Mate TC at a local pawn shop for $10. The "Bayonet" on the side that fits in the camera is missing the spring so it rattles loose. The TC appears to work fine, I can put it on and take it off with no problem. I originally bought it thinking I would take the glass out of it and use it as an extension tube for macros but now I'm wondering if I should.

So what exactly does the "bayonet" on the camera side do anyway? Also, just asking for opinions here, should I leave it alone to use as a TC or go ahead and take the glass out?

Thanks in advance.

11-28-2007, 05:22 PM   #2
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Your question has me a little confused. There's no "spring" on any lens or TC mount that I've ever seen. The only thing that does have a spring is the M42 to K mount adapter. The lens or TC will have a little slot in the mount to allow the locking pin on the camera mount to lock and hold the lens firmly in place. See: Name:  lens mount.JPG
Views: 407
Size:  12.7 KB

Whatever way you use it, I'd be careful as the lens mounted to the TC could easily turn and fall off the camera if it's not locked in place. You could however take some measurements from another one of your lenses and use a Dremel tool to cut a small slot for the locking pin.

As for what to use it for. That's going to be up to you. Before taking the glass out I'd do some test shooting to see how well it works with your lenses. If it seems to perform well then maybe you want to keep it as a TC.
11-28-2007, 07:22 PM   #3
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Thanks for the reply Peter.

What I mean is the bayonet (I'm assuming that's what it's called) has a spring attached to it. That's the spring that is missing.



Not a good picture but I think you get the idea. I'm not sure exactly what this does and if it's a real problem that it doesn't work the way it should.

Actually I just checked one of my lenses. The bayonet I'm talking about appears to control the aperture . At least it does on my FA50 1.4. Since it's a TC I guess that wouldn't matter, just a little annoying.

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11-28-2007, 07:37 PM   #4
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What you are showing is the aperture linkage lever. That stops down the aperture of a lens when the shutter is activated. It has no effect on the TC locking onto the camera body and is not part of the bayonet mount. So if you were to add a lens like your FA 50mm that has the same lever to the TC it allows the camera to stop the lens down.

11-30-2007, 04:27 PM   #5
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"bayonet mount" is a reference to how bayonets connected to rifles using interlocking parts and not to the actual bayonet blade. Bayonet mount - Wikipedia, the free encyclopedia

As far as I know, teleconverters are supposed to have loose aperture pins until you mount a lens. The aperture pin on the tc is just an extension so the camera body can stop down the lens through the tc.
12-01-2007, 02:02 AM   #6
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The term bayonet is also used in electrics aswell (lightbulbs to be more precise).

the good old lightbulb was mostly available in 2 systems :

- Edison which is just a screwmount system (with diffrent sizes)
- Bayonet which has 2 pins that probably lock in a similar way as the Bayoney of a rifle (never saw one of those in real).

the Bayonet system was mostly used for places where vibrations could make the other system unreliable (like headlights of a car).

I think that the bayonet (and also Edision) mount systems are beeing outdated since I see more and more of those newer system they use for Halogen (spelling ??) lights.
12-01-2007, 02:24 AM   #7
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QuoteOriginally posted by Cloudy Wizzard Quote
The term bayonet is also used in electrics aswell (lightbulbs to be more precise).

the good old lightbulb was mostly available in 2 systems :

- Edison which is just a screwmount system (with diffrent sizes)
- Bayonet which has 2 pins that probably lock in a similar way as the Bayoney of a rifle (never saw one of those in real).

the Bayonet system was mostly used for places where vibrations could make the other system unreliable (like headlights of a car).

I think that the bayonet (and also Edision) mount systems are beeing outdated since I see more and more of those newer system they use for Halogen (spelling ??) lights.
The bayonet mounts are still going strong. They're the standard (at least where I am) for marker lights, turn signals, and tail/brake lights.
12-01-2007, 07:16 AM   #8
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that's the aperture coupling lever. it's suppose to be loose. once the lens is mounted it should not rattle. i agree about trying it out 1st as kiron is a highly respected lens maker.. if you look even your kit lens has this lever.

12-03-2007, 08:44 AM   #9
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I'm leaving it alone for now. I need to try it out and see how the quality is but the weather here has been bad lately. It appears to be in pretty good shape, the glass is nice and clear and there's not a mark on it other that the glue from the price sticker I haven't taken completely off yet. It still rattles a little with a lens attached but I can live with that.

I've been on a buying spree on "that auction site" over the last week or so, something like 9 more TCs, 7 lenses and a couple of other odds and ends. I'm a tinkerer so that should give me plenty of stuff play with. I could have just bought some cheap extension tubes but this will be much more fun...
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