GIMP is good. Complicated, but providing excellent fine control.

Am I right in thinking that it combines some of the features of Adobe Illustrator as well as Photoshop?

I'd almost agree, and for many types of shot in typical shooting conditions this may be true. Two caveats though. Firstly, in conditions of mixed lighting RAW must surely give most post-processors greater latitude to render the seen as it was. And secondly, RAW gives greater latitude for the post-processor to render the scene as they want it.

A huge difference between them. The Pentax-F 1.7x AF adapter is excellent and loses no more than half a stop of light, but it will cost several hundred squids and really, if you have a first rate prime lens you might as well just crop the image.

This helps ...

http://heavens-above.com/

Yesterday I went out with two lenses and a brace of MZ-5n, one each, colour and bw film. Some lens swapping took place over the two rolls. Some filter swapping too, as the haze inclined me towards using a polariser and/or yellow filter.

At no time did it occur to me that I might have wanted to use a different lens, the 31mm and 77mm were just fine.

Many of the Meyer lenses were designed intelligently; iow, a relative amateur can take them apart and put them back together again. I don't know the Domiplan but it may be that the iris will unscrew as a unit once you've unscrewed the rear cover. Once you've removed it, soak the unit in Ronsonol until clean - maybe 24 hours, but probably just a couple of hours.

The grease comes from the helical focusing which tends to leak over time. If the focus is at all stiff you could (remove the glass elements first) drop some Ronsonol between the tubes and work the focus till it becomes looser.

Ronsonol dissolves grease and oil but leaves no residue. It's perfect for old shutters (I use so much I should buy shares) just don't breathe it in (or smoke) while you are working.

Test out your 50mm wide open. I'd say it's the only lens you have that approaches the shallow dof you want. Look for a faster lens when you can.

The evidence for life in this galaxy implies the possibility of life occuring in every galaxy, and there are billions of them. There might well be other occurances of life in our galaxy, but time and distance militates against much contact.

I like the peppercorn analogy. The nearest star to our own is a mere four light years away, but that's really quite a long way. Reduce the Earth down to the size of a peppercorn, and the sun to about the size of a small pumpkin (eight inches) and the next pumpkin would be four thousand miles away - like from London to Miami. If Proxima Centauri had habitable planets then you could imagine one peppercorn in Trafalgar Square and another somewhere in Disneyworld ...

Great material for fiction, of course.

43mm or 77mm.

But I've often used a Biotar or Helios 58mm f2. Yes, they are preset or stopdown lenses, but at f2 ...