I bought a Quantaray QB=7500 flash for a Canon Rebel S 35MM camera years ago. I'm wondering if an adapter module for these old flash guns is available to make them work with a Canon DSLR. Anyone know?

TexasFire

 

Yes and no.
The problem with many flash units for film cameras is that the pin voltage on the older units is too high and can damage the sensitive electronics on the digital camera.
This site lists the trigger voltage on your flash at 5 volts which should be safe for your Canon camera.
There is a device available that may protect your camera and it is a Wynn Safe-Sync that has a sensitive circuit breaker in it.
The cost of this however could be a payment on a Canon flash unit.

One thing is if you use this flash on your digital camera it will not communicate with the camera and will only work in manual or maybe semi-automatic mode.
Some older flash units have a built in automatic function where you input the cameras manual setting and the flash cuts off when it gets enough light.

I would suggest that you search for more detailed info on this subject before you decide what you are going to use.

For manual mode with a flash set the camera to M and set it to F-8 and 1/125 in daylight.
Some digital cameras have 1/125 speed as the maximum flash sync speed.

 

Thanks Greg, it just makes sense to purchase a new flash. That Quantaray was an amazing flash on my old 35mm as it metered thru-the-lens with stunning accuracy. I'm about to believe my old Stroboframe flip frame and my Quantum battery pack are the only things I can take forward into the digital realm. My Tamron 28-200 lens worked on the digital body but I will probably just shop for new. Your input is greatly appreciated.

TexasFire

 

If you want to make some use out of your old flash you could consider purchasing an optical flash trigger unit that connects to the old flash and triggers it when it senses light from another flash.
There is no connection to the camera and it could be useful for fill light.
They are quite inexpensive and pose no risk to the camera.
For a few dollars more you can get a transmitter that attaches to the camera and fires the flash by radio waves.
You can get high quality units like this for a few hundred dollars or to experiment with it an offshore unit for around fifty bucks.