I've been noticing some people finding my page on Google searching for more detailed information about the 383 Super. Since the 383 Super is a reasonably priced manually-controllable flash, suitable for both on and off camera use, it's experienced a little bit of a resurgence in recent times. Vivitar has responded as well by putting the 285 back on the market.
If you are using an older camera, you are probably fine. If you get the absolute latest version of the 383 Super, you are probably fine. If you are shooting a relatively new camera and have a 383 Super of uncertain vintage, you want to check.
Take a voltmeter and put one probe on each of the metal contacts on the shoe. If it reads something around 6volts, it's fine. Otherwise, you may have a problem, depending on your camera.
If it's too high, you can always use it off-camera or get a Safe-sync adapter.
Also, remember that there's no communications between your camera and the flash in the way that the dedicated modern flashes have. If you have a setup like that, the camera will work from the meter and your exposure settings and figure out the flash settings for you. On the other hand, if you want to have a proper set of four lights and be able to cart them around without breaking your back, you are going to spend a lot less money with four 383 supers than four flashes that will properly integrate with the system of your choice.
See the hole on the front with the green ring around it? That's a sensor. In the automatic modes, the flash will use that to figure out when it's done putting out light. It goes without saying that if you are shooting and accidentally cover it with your fingers, Bad Things will happen.
Now, let's turn the flash over. I've indicated the various sliders.
You want to make sure that your ISO/ASA slider is set to whatever ISO you are currently working at.
The mode slider has three automatic modes, each one a different color, plus manual modes. Each automatic mode will indicate an f-stop and a range. The red "A" gives you the least range but the most power so you can shoot with the lens stopped down. The green "A" gives you the most range but you need to shoot with the lens opened up. The yellow "A" is in the middle. In any of these modes, it will use the sensor on the front to determine when to cut off the flash. Also, you want to leave the power slider in "A / full" mode to get the range right. Personally, I usually just use the green "A" mode because I like to shoot fairly close to wide open.
Now, what happens when we are in "M" mode? Now, the power slider controls what the flash will do and the sensor isn't being used.
The test button will fire off a flash. This is good for blinding your friends at parties after they make a bad pun. If you are in an "auto" mode, the "auto OK" light will blink green for a second to let you know that the flash was able to put out enough light.
Generally, I start out by doing a meter reading to see what the scene is like.
Let's start with the situation where you'll feel awfully funny grabbing a flash -- a nice sunny day. Let's say that our meter reading is 1/125th and f/16 with 100 speed film. Why do we have our flash out? Well, we'd like to fill in the shadows. Remember, just because your eyeball, the result of millennia of evolution, can peer into the dark shadows in front of you while the rest of the scene is bright and sunny with astonishing ease doesn't mean that your camera, the result of a little over a century of dedicated research, can do it quite as easily.
So, turn on the flash and set it to the red "A" mode, which indicates that f/8 is the aperture setting. This is actually want we want to happen. What happens is that the flash will make sure that the entire scene is exposed for f/8... so underexposed 2 stops. It's going to do this within the first 1/1000th of a second of the shutter being open. The rest of the 1/125th of a second, we're collecting the natural light in the scene. This will bring up the shadows so that you can see some detail in them that you wouldn't be able to see otherwise.
You probably want to experiment. You may like it better with more like 1 to 1.5 stops underexposed. This prevents you from having your friend silhouetted against the sky when the sun is behind them.
You can also usually get away setting the flash to "M" mode and 1/16th power and setting the aperture setting to whatever the camera says for you to shoot.
Now, let's say that we're indoors and the light is more like 1/30th, f/2.8. You might want to carry around a set of color gels for situations like these because the flash is going to make light that is colored like daylight and most light is either incandescent, which is going to be orangish, or the light is going to be fluorescent which is going to be greenish, unless it's very high-end. A sample book of theatrical gels is really what you want... they fit right over the flash front without needing you to cut the book apart or anything.
Remember that the light on-camera is kinda sucky, so you want to avoid using it as the primary light. At this case, we've still got some light to work with, however, so we'll set it to the yellow automatic mode. In this case, the flash is going to help make the lighting "snap" and make any camera shake less noticeable.
Now, let's say that the lights are out and we've got 1/2th, f/1.8 exposure readings. Time to get creative.
Usually I look for a white surface. Any white surface. A handy wall or ceiling. Point the flash at it. If you've got a nice wide white ceiling, don't point the flash straight up, but try and turn it a little to the side. I tend to use the green automatic mode most of the time.
The various flash diffuser things can come in handy in this case. I usually just tape a piece of office paper to the flash. Remember, if you keep the flash about the same distance from the camera and still pointed at the same spot your camera is pointed at, you can use a cable to get some distance between you and the flash.
Be careful about reflective objects. The sensor just sees what sort of light is roughly in front of your camera. If you have a shiny object in front of you, it will be so reflective compared to the rest of the scene that it will cause the flash to shut off too early. In this case, you want to use the "M" mode. Transfer your aperture setting and move the power setting slider so that it matches your focusing distance.
Now, all the flash diffusers and lighting toys in the world aren't going to hold a candle to taking the flash off-camera.
A Wein Pocket Peanut is attractively priced, but you don't want it. It won't work reliably into the PC connector that comes with the flash. The Wein hotshoe slave will work better.
You can use the eBay gadgetinfinity radio slaves or a PocketWizard, too. This way you won't trigger off of everybody else's flashes.
The "A" modes aren't going to work out so well. Using the "M" mode, you can use the calculator on the back to figure out the desired aperture setting and measure the distance. Simply measure the distance to your subject and adjust the power slider so that it matches your desired exposure setting. Usually I just use my digital camera to check the exposure, this will work even if I've got a bunch of flashes and the flash is bouncing off an umbrella.
Most of the hotshoe slaves have a threaded connector on the bottom that will screw into either a tripod or a light stand. I usually get an Umbrella / Hotshoe adapter for all of my light stands that holds an umbrella as well as providing a tiltable mount for the flash.
The biggest umbrella you can make work is probably in the 40"-48" range.