These days I use a Sony A350 which take the old Minolta autofocus lenses.
But the TTL exposure control on the old flash is not compatible with the new camera.
I had no luck finding an affordable solution until I saw the Ray Flash adapter.
It is a Fiber-Optic light guide which slides over a standard flash unit. The optical fibers port the light to the ring around the lens. The TTL of the camera controls the light output of your flash for a perfect picture every time, well, almost.
It works great for me!
I found one on Amazon for $83.00. https://www.amazon.com/gp/product/B001R ... UTF8&psc=1 This model is discontinued and newer models are much more expensive, but you can probably find a used one on eBay.
It's hard to find a TTL Ring Flash that uses Xenon Flash Tube for freezing motion. It's almost impossible to find one at an affordable price.
This widget is a nice compromise.