Gave this old lens a whirl yesterday and had a lot of fun with it. I need to use a tripod to do it justice, but here are a few quick snaps from around the edges of our garden. It's a pretty good affordable close up lens if you don't want to shell out lots more on a new macro:

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Please no more mention of surprisingly good lenses. It does not help!!

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Oo err, can feel Takumars calling.... Or even wierd Russian lenses....

Good luck finding one! The Tokina is like hen's teeth. That said, I think someone did put an ad in the marketplace at Pentax Forums recently and managed to acquire one, so might be worth posting there too in order to increase your chances of tracking one down.

If it makes you feel any better, I recently purchased one for £100 and thought it was worth every penny and then some. It's a great lens, and now sits on my camera as standard lens unless I need to use something else.

For somewhere like Botswana, I think the range and compactness of the Tokina 80-400 would take some beating.

On a trip to the Okovango Delta and Linyanti, the lenses I am glad I took with me were 55-300 (the only telezoom I had at the time), Tamron 500 (used more than I ever expected to), 70mm DA Ltd (great for smaller creatures and in poor light as it's good even wide open) and Voigtlander Nokton (as well as being a stunning lens for general landscape and sundown etc in Botswana, f1.4 really helped at night time - I got usable shots of wild dogs in the evening with this when all the Canon crowd with me gave up despite all their long white lenses!)

For macro, you could do a lot worse than either use an extension tube with your existing lenses (which does cut the amount of light entering the camera so will extend shutter speeds), or using a close up filter on the front (I've used Marumi ones, that are relatively cheap in normal filter sizes, and not bad at all). Another option is a reversing ring as suggested by Mat.

The best normal lens I've used that does a pretty good job at close up is the Sigma 17-70, which also happens to be a great upgrade to your 18-55 kit lens. It is, however, bigger and heavier. If you hadn't already got the twin lens kit, then something like the Tamron 70-300 would also be a good cheap way into close up photography, but on the assumption that you already now have the Pentax 55-300, I don't think it is a worthwhile step in your case.

Otherwise, there are a wealth of secondhand macro lenses to look out for. Focal lengths around 90-100mm work well for most people, and Pentax, Tamron and Sigma have all made great lenses between 90-105mm. There are also some legendary Vivitar macro lenses, but you need to choose carefully.

Also look out for some of the older Pentax 1:2 manual lenses that were sold as "macro" - specifically the 50mm and 100mm f4 SMCM lenses. Both are beautifully made, and produce great results.

Jon - I recently bought a Tokina 80-400 and think that unless you want to spend a fortune, it is a pretty decent performer. Build quality is great, it's surprisngly compact (but quite heavy) and has surprised me by how well it keeps things sharp towards the edges. That said, its centre performance is not significantly better than the 55-300 DA lens, (in fact at some focal lengths, the 55-300 is superior) and it does have some mild fringing. If you can pick one up at a decent price, I'd say go for it. But I wouldn't get sucked into a bidding war!

By the way, my cost-effective 500mm option is an old Tamron SP mirror lens. See the other related thread on this site over the past few days. In terms of sharpness, it blows the Tokina out of the field.

At 24mm, in addition to the Pentax lenses, the Sigma Superwide is very well regarded. I have a Tamron Adaptall 2 24mm/2.5 (later version, but the optical formula is unchanged) and have been impressed with that too. The Tamron's can be found quite economically.

If you go wider, the 20mm f4 SMCM is a nice lens, not terribly much bigger than the current 21mm DA Ltd pancake, but likely to cost quite a lot more than 24mm.

I think some of the newer Pentax compacts look quite interesting. The W90 looks like it plays to a niche that Pentax is aiming for: hard-wearing and durable camera that's ready to go wherever you want to take it. The i10 is I am sure as competent as most non-enthusiast digicams out there, but at least looks nicer.

However, other than that, I don't think Pentax really have the model range with the capability to take on either the high end Canon or Lumix models (I would certainly add the latter to the collection of best compacts you can buy), or some of the best that Ricoh has to offer.

That said, I think the recent moves to produce cameras that differentiate themselves from the mainstream is probably a very smart idea - let's hope there is more to follow, as people are influenced by buying products that involve good design as well as capability and function.