I'll see if any bellows are left, the only ones staring at me obviously at this minute are some for Pentacon 6, which doesn't help!

I'm glad to see you thinking about things Nigel. You might need different names for your terms, as we already have input and output used in a slightly different way. Input sharpening is the sharpening set in the RAW converter, creative sharpening is done whilst processing an image in Photoshop (et al) and output sharpening is that applied just before outputting the image to the printer.

All of this is at the computer stage. The camera is a capture device that produces a RAW file, but also has limited processing power to produce a JPEG file as well. I say limited, but it's all relative and it can be quite powerful in its own right.

How many macro options do you need? 50mm and 100mm Pentax macro lenses are widely available, both now and since the days of the screw thread cameras. We also now have a 35mm macro. There was even a 200mm macro at one point, much sought after.

Other makes have macro lenses on K mount and always have, then add all the M42 screw mount options.....

I'm not sure why you refer to extension tubes and bellows units? If wanted, these do still exist. When I've offered screw thread or K mount bellows on eBay sales have been few and far between, so I guess demand isn't really there.

Although I shoot JPEG almost all the time, I do use DNG as well. Adobe Camera Raw seems to do the job, nestled comfortably within Photoshop CS5.

There's also an Elicar 90mm that gives greater than life size reproduction. There are exceptions to everything and I think Zeiss even made some f/2 macro lenses.

If looking at manual focus, some are not cheap even now, so I'd think about a screw thread or early bayonet 50mm f/4 or 100mm f/4 from Pentax - very compact and razor sharp, with a flat field.

There's nothing wrong with the Tamron 90mm f/2.5 either, although it is bulky and heavy by comparison.

All the macro lenses are excellent. They are limited in their maximum apertures, but this means that relatively simple lenses can be made that have superb performance. Even the screw thread Takumar lenses will still do the job.

I've looked through your Facebook images, and there are some very interesting and innovative shots there. I've clicked "like" on quite a few of them.

I'm not suggesting this is the problem in this case, but spot metering used incorrectly does cause some a fair bit of grief.

A phone is a small carry anywhere, always, device, not a DSLR. I can't see many people wanting to lug a DSLR around everywhere like people use phones.

The important thing is to get consistent results, so if you achieve that by applying +0.7EV there's little harm in it. It may be that the meter calibration if off, but if it's always the same it isn't a problem.