The Vivitar 283 was introduced in 1970 and at that time, it was a high power top-of-the-line shoe-mount flash. Its thyristor circuit was extremely advanced for its time because for any film speed within its ISO range, it provides a selection of four different f-stops for automatic flash operation plus exposure-check indicator. If the flash is used off-shoe, there is also an optional remote sensor cord (SC2) that allows the sensor to be detached from the flash and pointed to any desired direction for more accurate exposure. Also, the 283 is very powerful. At ASA100, it has a giude number of 120 with full coverage for a 35mm lens (on 35mm film or full-frame sensor). How powerful is this? For comparison, according to information source on the Internet, Nikon SB-900 is rated at approximately GN111 at ASA100 when its head is zoomed to 35mm position. Moreover, like many other professional level flashes, the 283 has a connection jack (beside the sync cord connection, see photo above) for external power-pack. It could be for these reasons above that a total of 3 millions were made just within the first three years after its introduction!
Even today, the 283 and its modern successor 285HV are still being used by many serious amateurs and even professionals. Both models, especially the more flexible and DSLR-safe 285HV, are still in high demands in the used market. 283 is less flexible because it does not have a zoom head (full 35mm coverage without wide-angle attachment) and manual power control built-in like the 285HV. An optional vari-power module (VP1) is available for power output control (in steps of: 1/64, 1/32/, 1/16, 1/8, 1/4, 1/2 and full power) but it is getting harder and harder to find today. There are also DIY modifications of the flash on the Internet but they require certain level of understanding and skill in electronic circuits. Also, the 283 (and many other flashes in the film-era) has a high enough triggering voltage to cook the sync-circuit of a DSLR when it is being triggered by the hotshoe or PC-sync port but of course, it will be fine if you fire the 283 by using an optical or radio slave.
One thing strange about Vivitar flashes (283 and 285HV alike) is they have a non-standard(ISO) PC-sync terminal and thus require a proprietary sync cord. To my knowledge, Vivitar made two of these and they are the straight 1′ PC-1 and coiled 3.3′ PC-31 (photo above). My 283 does not come with a sync cord so I need to pay extra for one but given its price ($10CAD!!!), it is still a very very good deal. However, poor me bought the boxed one in the photo above for only $1CAD AFTER I got my first used one without a box for $8CAD (so now I have a spared one…might be for the future purchase of a 285HV?)
Status: Disposed, replaced with a 285HV