Depends if you mean Pentax, or Pentax fit.

Assuming you mean ground-to-air photography, the best Pentax lens currently available new is without a doubt the DA 55-300 (not the DA-L version, which although optically the same does not have quick-shift).

I've shot a couple of Farnborough airshows in recent years using the 55-300 exclusively, and I'd say it's quite a bit better than decent. You can have a look at the best of my 2010 show pictures here.

However, it is a little on the short side. In Pentax fit, the best is probably now the Sigma 50-500.

This year at Farnborough I had a Sigma 50-500, which I'd say is significantly better (only because of the extra length), albeit at about 5x the price. It's also very heavy in comparison.

Neither of these lenses is weather-sealed. However, if it's raining, there isn't going to be much of an airshow

For air-to-ground, a wider rather than longer zoom would be better.

Worth verifying what happens if you switch off horizon correction for exactly this reason.

Not being funny, but have you asked your nephew if he knocked it over or banged it in any way?

If you make it very clear that he's not in any trouble, and explain how important it is to know if there's a possibility of damage, you may get an honest answer

Very true, much faster than 1/100 and they tend to look pretty rubbish.

And likewise that Osprey that was displaying at Farnborough. 1/125s, in this, and still hardly any rotor blur. A nice dust spot, though, before someone points it out

No faster than 1/250s for the high performance aerobatic monoplanes.

For WW2 aircraft and earlier, slower still.

And a PM from me.

Yes, I understand that bit

I just meant that unlike in AF-S, if you press the button all the way down in AF-C it will fire whether it's in focus or not (???) whereas in AF-S unless you change the custom option, it only fires if it thinks it's in focus.

Wuss

I absolutely LOVE that one of the two Tornadoes. The front one is a touch soft, but catching the back one like that in the front one's exhaust is really, really excellent.

You should do a lot more with that one, I think - it's an absolutely marvellous capture and very unusual indeed.

BTW - if you're going to play with highlights and shadows, you need to boost the midtone contrast as well.

That'll be the spot metering, especially if the background is cloud.

Still, if you can keep the thing focused using centre-spot only, you've a steadier hand than I.

For most of my ground-to-air pictures, I use centre-weighted metering and AF-point auto select, which mostly doesn't trash the highlights and makes it easier to keep the subject in focus.

However, if the background is white cloud (which is MUCH brighter than blue sky), that means a lot of shadow recovery is often needed.