by IanKendall » Oct 5th, '09, 23:14
The book by Ed Mishell explains the use and construction of a Miller gravity hold out. A few years ago Alan Greenberg made a DVD explaining some of the routines from the book.
Michel Vernet from Argentina makes a Gravity holdout (GHO) called the Invisible Hand. This also comes with an attachment set which will greatly increase the number of effects that can be done. His 3 DVD set, also called the Invisible hand is required watching for anyone who wants to use a GHO.
There are a few other commercially available systems, ranging from the quite cheap (the Super-M) through the more expensive (Antonio Roberto's Perfect Holdout) to the ridiculously expensive (the Fitch-Kohler system).
One thing to remember - GHOs take a lot of practice to be able to get the most from them. They are easy to use badly, but to put them to their fullest use, whichever system you get or make, will take a good number of months of diligent work. They are the antithesis of 'self working'.
Having said all that, if you are willing to do a bit of DIY to make one up, your best value for money is the Vernet DVDs. They are a bit more expensive, but the contents far outweigh the Greenberg DVD. However, if you just want to dip your toe in the water, as it were, the Greenberg disc does have a PDF of the book, so you can kill two birds with one stone.
Hope that helps,
Ian