I have an old Sony speedlite and a new Canon 7D

[Moby]

Ihave an old Sony Speedlite I dug out of a camera bag I've had stores for over a decade.

It's a Sony HVL-F32X  Nothing fancy by todays standards.
I purchased a Canon 7D and am still learning about it.
My shooting camera when I had my studio was a Nikon F4 .
That tells you how long I've been away from the art.  Talk about a new learning curve.
I am wondering if the old speedlite will work until I can get one designed for the Canon 7D

I also have a Nikon Speedlight SB-28DX 
Any idea where I can go to look up compatability?

[Alex]

Sony and Minolta are compatible, Nikon and Fuji are compatible and Canon have a different fit all together

[Mt Spokane Photography]

Old flashes, or other model flashes might work in manual mode, but they are not going to integrate with Canon's flash system.  You spent a lot of $$ on the 7D, why not get a compatable flash.
Even a low cost one like this refurbished one for $135 can be controlled by your 7D as a off camera flash.
http://shop.usa.canon.com/webapp/wcs/stores/servlet/product_10051_10051_310916_-1

[Marsu42]

Ihave an old Sony Speedlite I dug out of a camera bag I've had stores for over a decade.

If it works then only in manual mode (just like older Canon speedlites from the pre-digital eta which only do a-ttl) - so forget it, I tried, it's not worth the hassle. There are no ends of used and 3rd party e-ttl flashes around.

[brad goda]

compatible yes ... if using in manual mode and connected via syncro cable and flash peanuts to trigger multiple units not a problem....
light is light.
but if you want TTL compatability... no no no not worth the thought or hassle.