Getting video Hi8 8mm tape into MacBook--via another camcorder??

Depends on the Sony Camera.
I'm not familiar with that particular model.
Check your manual.
I do exactly what you are wanting to do with my old Canon ZR40.
Works great even though the ZR40 does not even work anymore as far as running a tape through it (eats the tapes).
But my Sony Model HVR-A1J does not have the capability to go from analog to digital.

I really don't want to have to purchase any additional equipment.

You may have to.

To get your Sony Hi8 video into iMovie, look at the Canopus ADVC300. Audio and Video go in, FireWire comes out. It also comes with a nice Macintosh application that works flawlessly with iMovie 06 and iDVD 08/09 (I have used it a few times with iMovie 08 and 09).

The program that comes with the ADVC300 has some nice filters that can improve video and audio of the source material. The ADVC300 will take Audio and Video from any source and convert it to FireWire (iMovie will treat it like a camera).

http://www.canopus.com/products/ADVC300/index.php

I would use iMovie 06 with iDVD 08/09, why?

iMovie 08/09 uses 'single field processing' meaning every other horizontal line of the video is thrown out, which reduces the sharpness of the footage. iMovie 06 uses ALL of the image to form the video.

If your primary workflow is editing DV clips and making DVDs, iMovie '06 is better suited. Your movie will arrive at iDVD in DV format, which is an ideal match for making a DVD: same resolution, same pixels aspect ratio, and original quality. If you share your movie from iMovie '08 / 09, it gets re-rendered at 640x480 or less, and then iDVD upscales it back to 720x480. The end result is obviously not as good.

iMovie 06 and iDVD 08/09 is a "lossless" combination.

Yes, you should be able to easily connect the two camcorders. (I did it with my digital mini DV Sony and my older Sony Hi8 camcorder).
However, I first recorded from the Hi8 onto miniDV tapes. It took longer, but in the end it was easier and faster to do it this way. I don't remember if I actually tried to connect both and through-put to computer.....I wanted miniDV copies of the Hi8 tapes because my Hi8 camcorder is starting to fail and I couldn't rewind tapes on it.
I had a Hi8 VCR that wouldn't play properly, yet its rewind worked, so I had to switch back and forth to get the Hi8 tapes to play and rewind.

I had about 25 Hi8 tapes to put into my iMovies. I was afraid that all that forward and backward motion would ruin the original Hi8 tapes, and not wanting to go through this process during importing, I recorded all 25 onto miniDV tapes, and then used my digital miniDV camcorder for importing the footage into my iMovies.

And I heartily second Ziatron's suggestion of sticking to iMovie 6. Works great for me and my DVD movie-making!

Message was edited by: Beverly Maneatis

I agree with the comments on iM6 for import. I actually think the image is sharper.
I even use it when I want to eventually end up in iM8 or 9.
I just move the files from the hidden folder in iM6 into a folder in the iMovie events folder.
That way I am not required to wait for every individual clip to create thumbnails.
I can just start iM8 after moving all the files and go take a break and do something constructive while the process is accomplished on all the clips I moved.