The time is probably right to upgrade now then Jonathan! (Unless you go for a S/H option). You can't expect Pentax to keep all their old models in production in perpetuity. Plus any new lower/midrange models will likely be 24MP in a years time anyway....

I'm not sure about 'The use of aperture to control DOF seems to be a dying art in photography these days'. There seems to be an almost obsessive focus on shallow DOF, it's one of the main reasons many people want to go FF, and it's the main reason that Sigma have offered this fast 18-35mm lens - to give the 'Full Frame' shallow DOF look on APSC cameras.

There are certain instances when you do want sharpness across the frame, e.g. most types of landscape shots. The shallow DOF thing is more for portraits, candids and close ups. The ideal lens would be sharp across the frame when stopped down, and provide lovely bokeh when shot wide open (and soft edges would not matter here although not necessarily desirable) but with good central sharpness.

Found myself a little emotional last night. If there was one great man in our lifetime, it was Mandela. RIP

https://www.youtube.com/watch?v=AgcTvoWjZJU&feature=youtube_gdata_player

Clearly when people ask for a hotshoe on these little cameras, it's for adding a radio trigger. The sync speed of these little cameras is much higher than DSLRs, which makes them interesting to strobists.

It's possible to use optical triggers though, as this guy demonstrates http://www.youtube.com/watch?v=JZY3lYIBtZ4

Fortunately, not that much space at least!

The DA and XS versions look much better.

There are a few threads on it on the other Pentax forum (the US one). It looks okay for the money but I don't think it's as good as the Pentax-M 85/2 or Samyang 85/1.4.

Not in the context of that discussion, Algi! But of course if you want to get close to your subject to create that exaggerated perspective, you need a WA/UWA lens. So in practice you do need different focal lengths to play around with perspectives in a confined studio setting. You can crop an image to get 'telephoto compression' but you'll lose resolution by cropping and as yet there's no way of 'uncropping' an image to get a wide angle effect.

I hear they're ideal for cracking nuts with....

We've been through this on another thread, technically you are correct as everyone (except one person :lol agreed there. But obviously in practice you need to use different focal lengths to play with perspective creatively e.g. to give a hackneyed but easily visualised example, a dynamic UWA shot of someone pointing a gun where the gun looms large in the frame.

You can't achieve this with a 50mm lens - shooting from the same distance would not be possible. You would only get part of the intended composition in the frame.

Ralph, your shots illustrate why opening up the aperture to throw the backdrop out of focus (and to be fair moving your subject away from the backdrop) might be a good idea.

Fast lenses aren't just useful for low light, and just because there is plenty of light in a studio doesn't mean we should always stop down to f8, IMO.