Hi 8 is an analog format, so you need to convert these tapes to a digital format so they can be stored on a computer. There are several ways to do this.
1) Here is what I did. Several years after the hi-8 format came out, the Digital 8 format was introduced. Some of these had the pass-through feature, meaning they could read the hi-8 tapes and pass them through as digital DV. I found one of these camcorders used on eBay for about $160. I used it to import all my 8mm tapes. Then I sold it on eBay a year later for about $140. You need a firewire port on your Mac for this.
2) There is a device called the EyeTV Hybrid. It attaches to your Mac via USB. You attach the video plug and the L-R audio plugs. The EyeTV hybrid also has an s-Video plug. The EyeTV Hybrid will also let you watch and record high definition TV signals through a rabbit ears antenna, or standard def signals through a cable box.
3) You can get a DAC - a digital analog converter - from companies like Grass Valley. These take the video and L-R inputs and convert it to DV through a Firewire connection. These produce good results but are pricey. Also, make sure your Mac has a FireWire port. Most do, but several recent MacBooks do not have a FW port.
4) You can use a professional service to do the capture for you and provide you with a hard drive containing your movies. There are many such services. I have used mymovietransfer.com with good results.
Good luck. This takes a bit of work, but it is worth it to preserve your memories.
