M4-2 Flash

[xasthur]

Hi all!

I have a M4-2 and I have a SunPak Auto 121C attached to the M flashsync on the back. To be honest I'm new to using a flash on a M film body and don't have much of a idea on what I'm doing with it. I just read the manual for the M4-2 and it gave a little info chart, but I don't really understand what it's saying.

I see that there's a little flash indicator on the shutter speed dial. I don't know if when I want to use a flash must the camera be on this setting which I'm assuming is 1/60th? Then I choose the aperture based on the lighting I'm in? I'm just a little confused so if someone could explain it for dummies like me I'd appreciate it.

I'm been using the camera with the flash and have just been guessing with the settings I'm using. I'm not done with the roll yet to see how they turn out and to judge if what I'm currently doing is working at all.

 

[madNbad]

The shutter speed dial has as lightning bolt at 1/50th that is the primary setting for electronic flash. With the flash set to “A” (auto) the green numbers show the proper aperture setting corresponding to the ISO for correct exposure from 1 foot to 12 feet. The other numbers are for calculating manual mode. It’s a nice little flash and with a little practice you may find it more useful.

 

[Godfrey]

For the M4-2, here are the three steps you need to do.

1- For simplicity's sake, just suppose that the flash is going to provide all of the light required for the exposure. So you set the shutter to the electronic flash mark.

(The electronic flash sync marking on the shutter speed dial marks the shortest (fastest) shutter speed that you can use with electronic flash. It's about 1/50 second, not quite 1/60. You can use any shutter speed UP TO that mark ... the longer the exposure, the more ambient light will be included in the exposure. But we won't go into that here...)

BTW, you shouldn't need to plug the flash into the flash terminal on the back of the camera because the M4-2 was the first Leica M to have a hot-shoe, and the foot of the flash unit in your photo has the machine electrical terminals. You should be able to just push that flash unit into the camera's shoe and it will be connected.

2- With the shutter speed set and the flash mounted and powered on to the A position, look at the table on the back of the flash. Going down the list of ASA (ISO) values on the left, pick the one that matches the film speed you're using, and use the green f/number across from it. ... If Tri-X, that'll be 400. Look across to the green column in that row in the table and you'll see f/8. Set the lens to f/8.

The A setting is the Automatic flash metering setting. A small photocell on the front of the flash unit will read the light as the exposure is being made and stop the flash at the appropriate time in this mode.

3- At this point, you're ready to make exposures. Be sure the "ready" light on the flash unit is lit. Keep the subject within the range from about 4 to 11 feet from the camera, then focus, frame, and shoot. Leave the shutter speed selector and the aperture ring alone ... The exposure will be set automatically by the flash unit's metering cell.

That's all there is to it unless you want to learn how to use manual flash exposure. But try this on a roll of film, process it, and see what you have done there first.

G

 

[David Hughes]

You can also calculate a guide number for the flash gun and then vary things a little. By that - and using the green list - meaning that you don't have to use 100 ASA film at f/4 for example.

Multiply 12 (feet) by 4 (aperture) and you get the guide number for that range of film speeds (around 100) as 48.

Now divide the GN by the aperture and you get the distance in feet from subject to flash and vice versa. So f/8 at 6ft or f/2 at 24 ft and so on.

For this you still use the same shutter speed as that is very important.


Regards, David


PS It's a good idea to search for a SunPak Auto 121C manual on the internet, there's bound to be one out there...

 

[Ko.Fe.]

This flash seems to have hot shoe. M4-2 does as well. I don’t understand why it is on the back terminal. And M or X?

 

[Bill Clark]

My recommendation, use the “A” setting (the switch with off, then a in green) on the flash which is, when on, automatically putting out the correct amount of light. Set your fstop per the green chart with the asa (iso) of the film in camera.

With your M4-2 use the lightning bolt setting (1/50) for the camera shutter. Can’t go with a faster shutter because of the design of the shutter on Leica cameras. Flash doesn’t care what shutter speed you use.

Back in early 1970’s I had an apartment on Henderson Avenue in Long Beach. I was finishing up active duty with the Navy.

There is a lot more I could mention but start here.

Simple.

Hope this helps you.

 

[xasthur]

Thank you all for the information you've provided and I can firmly say I have a way better understanding of how it works now.

One thing I've noticed is that when I do not have the flash plugged and it's set to A the flash does not fire at all even with the shutter set to the red flash speed. Unfortunately I do not have another flash to test so I'm not sure if something is off with the camera or flash.

 

[charjohncarter]

Try it at a slower shutter speed see if that works. Also, see if it flashes on 'A' when you use the test button. I've had a few flashes that I've had to be sure it is all the way into the hot shoe for it to work.

Check the manual it may say something about using that flash on your camera.

 

[David Hughes]

Thank you all for the information you've provided and I can firmly say I have a way better understanding of how it works now.

One thing I've noticed is that when I do not have the flash plugged and it's set to A the flash does not fire at all even with the shutter set to the red flash speed. Unfortunately I do not have another flash to test so I'm not sure if something is off with the camera or flash.

Hi,

It could be that there was enough light for the camera, film and lens and so on auto it decided not to fire. You find out when the film is checked...

But I'm not sure what you mean by plugged as it seems to have a hot shoe contact.

Regards, David

 

[Godfrey]

...
It could be that there was enough light for the camera, film and lens and so on auto it decided not to fire. You find out when the film is checked....

That can't happen, David. It's a simple automatic flash unit on a manual camera, the light sensor on it is tuned to read flash exposures, not ambient exposures.

OP:

First test the flash: Does it fire when the ready light is illuminated and you press the Ready/Test button? If that works, you can test the flash's hot shoe to be sure it's working ... Just take a little piece of wire and bridge between the side terminal and the center terminal when the ready light is lit. If it fires, all is good with the flash.

Testing the M4-2 is a little trickier. The flash contact is a momentary contact: you can wire it to a circuit tester and fire the shutter ..when it makes contact, the circuit tester's light or buzzer should signal but the signal will be very brief, you might not even see it. If you wire it to a Volt-Ohm Meter (VOM) with a swinging needle and a resistance scale, you should see infinite resistance until you press the shutter release and needle should swing momentarily towards zero resistance when you release the shutter. Again, the movement may be too short to see much.

Probably the best thing to do if you have a friend with another old camera and a flash unit is see if his flash fires on that camera, if your flash fires on that camera, and then try both on the M4-2. If both flashes work on that camera and neither work on yours, then the flash sync contacts in your M4-2 shutter need service.

Fun fun fun ... LOL! 🙂

G