Mamiya Press and flash

[Kenj8246]

Couldn't think of the 'proper' place to ask this so it's double-posted here and in general discussion. I want to use a Nikon SB-20 flash with my Mamiya Press 23. Both flash connectors appear to be posts with holes in the end. I 'think' I need a male-to-male PC cable. Am I full of horse hockey?

Thanks in advance.

Kenny

 

[sevo]

I have never figured out whether PC cables are male or female, but PC-to-PC you need. That said, I've seen male-to-female PC extension cables, but I don't think female-to-female (or whatever sex we'd attribute to the device side) ever existed.

 

[Kenj8246]

Thanks. I'm finding it difficult to find good information on sync cable ends. There seems to be a bunch of them.

I still haven't been able to discover how opening the shutter actually causes the flash to fire. It is my understanding that an electronic flash uses a charged capacitor to 'light' the bulb. What causes the capacitor to discharge over that sync cable? That apparatus has to do something.

Kenny

 

[sevo]

It is my understanding that an electronic flash uses a charged capacitor to 'light' the bulb. What causes the capacitor to discharge over that sync cable? That apparatus has to do something.

The electrodes in the xenon filled tube are connected to the high voltage condensator, charged to several hundred volts (usually 220-400V, as the same tubes are often also marketed for use in grid power devices). This is permanently (until the capacitor runs empty, that is) applied, but as the voltage is below the break-through voltage, the gas acts as a isolator. When the shutter is released, the sync switch in the shutter closes, causing a high voltage (but no significant current) to be applied to a wire (or mesh) mounted alongside the flash tube. This ionizes the gas, dropping the break-through voltage below the applied level, so that that the arc immediately fires. Automatic flash exposure circuitry would then either cut the flash-capacitor connection ("thyristor flash") or quench the residual current remaining in the capacitor, as soon as the sensing electronics register that the right amount of illumination has been reached.

 

[charjohncarter]

I don't know about your flash, but all my Vivitar, Minolta, and an old Braun work with the Mamiya Press AND at all speeds. I have some cord to hot shoe adapters for some, but really no problem.

This is a mix of ambient and strobe, also easy to do if you have a flash meter:

 

[Kenj8246]

More than I probably need to know but thanks for the explanation. 🙂 Of course, I still have my original problem but plan to visit a man this weekend who should be able to supply me with the cable I need.

 

[Kenj8246]

Thanks John. I do indeed have a good meter. Also have the assistance of someone who knows how all this works...I hope.

 

[Takkun]

The electrodes in the xenon filled tube are connected to the high voltage condensator, charged to several hundred volts (usually 220-400V, as the same tubes are often also marketed for use in grid power devices). This is permanently applied, but as the voltage is below the break-through voltage, the gas acts as a isolator. When the shutter is released, the sync switch in the shutter closes, causing a high voltage (but no significant current) to be applied to a wire (or mesh) mounted alongside the flash tube. This ionizes the gas, dropping the break-through voltage below the applied level, so that that the arc immediately fires. Automatic flash exposure circuitry would then either cut the flash-capacitor connection ("thyristor flash") or quench the residual current remaining in the capacitor, as soon as the sensing electronics register that the right amount of illumination has been reached.

Exactly this. In a nutshell, there's a voltage coming out of the flash (often higher on older flashes, contemporary ones are under 5V) and a switch in the camera synced to the shutter. Shutter closes, circuit engages, and flash discharges.
I've heard of people describing a camera 'sending' a flash signal, which isn't entirely true, unless you're talking wireless flash, but that's a whole different ball game.

Anyway. Yeah, for whatever reason Nikon flashes have a female PC connector, the same one would find on a camera body, so you'd need a

 

[sevo]

My Nikon flash manuals recommend the Nikon SC-11 or SC-15 - these should be more googleable than "PC cord" (which turns out a gazillion of computer connection and power cords).

 

[Kenj8246]

Thanks. Hopefully, my old friend will have what I need in some of the old boxes in back of his camera repair area.

 

[Kenj8246]

My Nikon flash manuals recommend the Nikon SC-11 or SC-15 - these should be more googleable than "PC cord" (which turns out a gazillion of computer connection and power cords).

At least a gazillion. 😀