Here's my favorite from my gunsmithing days when I was building custom rifle stocks.
1. Initial coating - Defthane satin polyurethane spray. The satin spray fills the woodpoers pretty quicly giving a deep-penetrating weatherproof base.
2. Top this with Birchwood-Casey Tru-Oil. Here in the states, it can be found at discount stores, such as Wal-Mart, in the sporting goods department. About $5 US for a bottle that will cover a good four or five gunstocks. Its a mixture of polyurethane and Tung oil. Dries in four hours which is fast for nearly all of the wood finishes. Build it up to the depth you want. Final coat should dry at least 24 hours.
This combination can be massaged into that beautiful deep glossy finish that a custom gunstock is known for. Probably not needed to that level on a camera, but it can be done if you want.
It is also very weather resistant, as much as needed for a camera unless your shooting out in constantly wet weather. The weather resistance is a necessary factor for a gunstock, and this does the trick.
Instead of the Tru-Oil, exterior polyurethane, tung oil, or Danish oil will suffice.
Well things are moving along quite well with my restoration/duplication project. I have decided on Tried and True Oil Varnish for one camera and Shellac for the other.
There are a few areas such as the inside of the back, and around where the bellows will be attached that need to be painted flat black.
Should I prime these areas with shellac before I apply the paint?
Any thoughts on what kind/brand of flat black paint I should use?
I would follow up the varnish oil with several coats of a fine paste wax, the first coat applied with a very fine steel wool gently rubbed. Buff, re-appply, etc.
For the shellac, if you haven't applied it yet, start with several thinned coats (I think alcohol as a thinner).
The more you can get the finish to permeate the wood the better. The wax seals it in and can be freshened up at regular intervals.
Post a few pics when you're done.