I have this old, very old flash. It used to be the standard, the work horse of all professional photographers in the 70s. Yes, that’s the 1970s. Every professional photographer had a Vivitar 283 flash. That was before the Canon EOS Speedlites or the Nikon Creative Lighting System.
I got a few photos in the manual mode, it worked. But when I switched to the Live View mode, it stopped working. The flash didn’t fire at the right time. What happened?
I thought that my Vivitar 283 had packed it in. Tried again it in the regular manual mode and it worked again. So it was something I did. RTFM. RTFM: Read The “Fucking” Manual or a more polite version of RTFM is: Read The Fine Manual. In this case I used the PDF version of the manual for searching.
If you use a non-Canon flash with Live View shooting, set the [Silent shoot.] menu to [Disable] (p:137).
— Canon 7D: Manual page 246
And it worked. My Vivitar 283 still work, even with the modern Canon 7D.
I receive from Stephen Dyer who’s “down‘under”:
Just a word of caution I think the Vivitar 283 has a very high trigger voltage approx 300V, depends when it was made. Canon EOS cameras are only rated at about 6V. The flash may work but It is very likely to blow the electronics in your camera. I have a couple of old flash units and I made up a low voltage interface so I could use them. That was a while back and since then I have purchased a couple of Canon flashes. Full info here: http://www.botzilla.com/photo/strobeVolts.html
— Stephen Dyer
My Canon 7D is still working, my Canon flash is still working is still working. I was lucky, nothing happened but upon hearing of the potential damage, I got rid of my old Vivitar 283 for a huge $9.50 Canadian credit toward some card carry case, not even cash.