Vivitar Zoom Thyristor 3500 Electronic Shoe Mount Film Camera Flash DM/C
I had used this flash a few times a few years back with great success on my Canon AE1 Program and with a Canon EOS Rebel X. It did not see much use as I was not a fan of flash photography back in the day. I did find the ability to bounce flashes off the ceiling and to extend to telephoto mode to be the most beneficial features not found in most flashed at this time and price.
It features a -7 to 90 degree angle of tilt with a 3 foot to 50 foot reach. This is outstanding for such a unit.
There is a sensor on the front with a four position manual slide switch on the back to set the flash duration. The color coded slider on the back matches up to the scale on top after you match the ASA on both scales. With both being set, you get a very accurate translation to the suggested f-stop setting on your camera. The top scale also gives information on the flash reach at that f-stop setting with lines on the optimal setting with the bottom slider selection.
The M setting is to shoot the flash wide open. It was an option I never really experimented with since the controlled settings were so good.
ASA ranges from 25 to 800, where I shot mostly at 400ASA. Today we use ISO which is basically the same in comparison, but different standardization organizations.
You can control the audible wind up sound and also disconnect the bottom control unit from the upper flash unit which houses the batteries.
It is to be used with a controlled or hot shoe mount. I believe the unit to be generic, but I am unable to find the instructions or any other information online. Check with your camera manufacturer or do further research if you plan on using this with anything other than a Canon Film camera.
The below is a review from someone on Amazon that I stole. Seems to elaborate more on this unit.
"Zoom - The diffuser lens on the front extends to concentrate the light from the flash into a tighter "beam" allowing illumination at greater distances. When you move the lens housing on this flash the exposure guide numbers are adjusted showing you how far away and at what F-stop you are exposing.
Thyristor - The light sensor (inside the circular part below the light emitting lens) uses a Thyristor device. I have heard that this may not work with Digital Camera. I have not tested it on digital, so check before purchasing.
This flash unit has a "DM/C" module marking which I know works with a Canon FILM cameras. I still believe that is may be generic enough to work on many different camera models, but please check if interested.
The module has the film exposure speed selector on it. (ASA and DIN markings) The camera senses the flash in the hot shoe and sets the shutter at 1/60th of a second and the F-stop at the highest setting of the lens (best depth of field). You set the flash speed selector to the closest of 3 settings for the amount of light the flash emits. The 4th setting "M" is the manual setting.
It has a power switch and "test" lamp/button on the back. There is a raised "bump" on the back of the unit that protects the test lamp/button from casual pressing. The flash can cycle quickly. Sometimes three consecutive shots can be made depending on the reflective characteristics of the target. A "full power" discharge is blinding and causes the unit to cycle for 10 seconds or more depending on battery condition."
Special note: Use fresh alkaline batteries and not rechargeable batteries. I have migrated away from alkaline and only use rechargeable which made testing this unit difficult. It took forever to wind up to flash. Not the units fault but my rechargeable batteries do not fully put out 1.5 volts anymore.
If you have any problems with this unit, please feel free to contact me for assistance. I have been a professional photographer both in film and digital for some time now.