I hate flying, although I have done it quite a few times. My wife will not go near boats. So flying or sailing all the way to Australia is out of the question. If I could drive all the way I would consider it as I understand it is a very nice place.
The 500mm f8 is a very nice lens with three problems that come to mind.
1) Under certain conditions It can have objectionable bokeh.
2) It is almost obligatory that you use a tripod in other than bright light, which somewhat negates the benefits of such a light lens.
3) f8 is all you have, therefore you must up the ISO. flash is not really an option at 500mm.
Anyone considering buying the 500 should know that it uses internal filters that are mounted in a holder. They are inserted in a slot close to the mount end. Minolta claimed that one of these filter must be in place at all times as it is part of the optical system (I doubt that). Mine came with a clear filter and a 4x Neutral density filter, a leather lens cap which holds the 4x ND and a very nice leather case. It is without doubt a classy lens. Those sold on eBay seldom have both the filters.