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I have an old Vivitar 1900 flash. New flashes have a lot of controls, but this one has two buttons and two lights. One button is on and off. The other one says test. One light is when flash is ready. The other one is the flash.

There is a table of numbers on the back. I don't know what it means. There are two columns labeled DIN and ISO. There are two rows labeled meters and feet. The rest of the table has numbers like 4, 8, 11, 16, and 22.

When I take pictures with my Sony NEX-6 and a remote control, they come out with a lot of white. How can I use this flash?

front back

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Vintage flash units are to be operated manually. In other words, you set the shutter speed and the lens aperture based on conditions. First the shutter speed. Check your camera manual to determine what shutter speed (speeds) you can use with a flash. This falls under a heading called synchronization. Electronic flash units are "X" synchronization. X synchronization means the shutter switches on a signal that fires the flash when the shutter is wide open. Likely this will be a shutter speed of 1/125 of a second. You need to check your camera manual. If you set the wrong shutter speed, you will be disappointed, as the picture will be blank or maybe an incomplete picture, one side blank etc.

As for the table, one column will be ISO (sensitivity setting) like 400 or 200 or 100, etc. A row will be distance in feet or perhaps meters, or perhaps two rows, one each for feet and meters. The rest of the table will be filled in with aperture numbers like 4 or 5.6 or 8 or 11 or 16 or 22.

You look at the row that has the same ISO setting as your camera. I advise setting the ISO of your camera to 400. Now look at the data on the 400 ISO row. Say you are about to take a picture of a friend who is standing 10 feet (3 meters) away. Now look at the aperture setting for this row. Say it is 11. We set the camera at f/11 with a shutter speed of 1/125.

Nobody said this is easy! A little study of the camera manual is what is needed.

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  • \$\begingroup\$ This is a true manual flash you're describing. Many vintage flashes will be telecomputer style, which again is operated differently. \$\endgroup\$ Commented Sep 3, 2019 at 15:30
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    \$\begingroup\$ @rackandboneman There are also many vintage flashes that only have one power setting and a chart printed on the back. That's what the flash described in the OP sounds like. (It has a chart on the back and seems to always use full power.) \$\endgroup\$
    – Michael C
    Commented Sep 3, 2019 at 20:06
  • \$\begingroup\$ Hello there, I have a question. The shutter speed is chosen to be equal to the flash synchronization time of the camera. But what if I want to use a slower time (for instance to get a blur effect etc)? How can I use the exposure guide table to determine f\. and distance? \$\endgroup\$
    – Kinka-Byo
    Commented Oct 6, 2019 at 14:59
  • \$\begingroup\$ You can use a slower exposure time because most flash synchronization shutter speeds are actually the fastest that work with the flash. In most every case, you can use a slower shutter and still obtain synchronization. However, the electronic flash, also called a speed light is super fast. Typically about 1/800 + of a second. Thus the short flash duration is likely the actual shutter speed, not the camera setting. True in feeble light, In strong light the camera setting likely rules. \$\endgroup\$ Commented Oct 6, 2019 at 15:59
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Old flashes designed for film cameras use a much higher voltage than modern ones and can damage modern cameras.

It sounds like you are overexposing your photos so you will need to lower ISO and/or stop down the aperture. The chart on the back will tell you how much to achieve a decent exposure at a given distance. Shutter speed is constant at the sync speed for your camera. You will need to estimate the distance to your subject first and then select an aperture and ISO that line up with that distance on the chart.

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  • \$\begingroup\$ Not all old flashes exhibit that problem, some do. \$\endgroup\$ Commented Sep 3, 2019 at 11:43
  • \$\begingroup\$ DPanswers: Flash trigger voltages \$\endgroup\$
    – xiota
    Commented Sep 3, 2019 at 12:42
  • \$\begingroup\$ I look up my flash in that chart. It say Vivitar 1900: 128 volt. How do I find out what will damage my camera? \$\endgroup\$
    – user86560
    Commented Sep 4, 2019 at 12:19
  • \$\begingroup\$ True. Schematics for some Sony APS-C cameras do exist on the internet, and the circuitry used for serving the hotshoe is certainly not 250V proof. \$\endgroup\$ Commented Sep 5, 2019 at 15:12
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    \$\begingroup\$ What external flash trigger voltage is safe for the Sony NEX? \$\endgroup\$
    – xiota
    Commented Sep 6, 2019 at 7:35
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The Vivitar 1900 is a very simple manual flash, that has no power level controls.

I would not consider it safe to use the flash in the hotshoe of your Sony NEX-6 because of the high trigger voltage. I would use a “safe sync” or wireless remote to trigger the flash to protect the camera’s circuitry.

Use the NEX-6 in Manual mode so you have full control over aperture and shutter speed. The NEX-6 has a max flash speed of 1/160 so 1/90 or 1/125 would be a good shutter speed to use.

The chart on the back shows you what aperture to use based on the ISO used in your camera, and the subject to flash shooting distance. Each time you change the flash to subject distance, the aperture will have to be recalculated.

If the flash is angled to the side of the subject, less light will fall directly on the subject so the resulting exposure will probably be darker. Trial and error will be necessary.

If your photos are too bright you can :

  1. lower the ISO to 100

  2. change to a higher aperture (like f/16)

  3. move the flash farther from your subject

In this example using ISO 400, the subject is 10 feet away from the front of the flash, so the aperture should be set to f/11

exposure guide

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