We're not just talking about higher engineering quality, but extra features as well.

The difference is very obvious when you examine the adapters.

I have a very nicely engineered Chinese adapter which fits smoothly onto the Q and does indeed enable use of K lenses. It's tricky, but it can work very well.

The Pentax Q adapter is much more substantially built and has a built in shutter and a built in aperture control mechanism. Electronic contacts enable the shutter to operate. The reason for this is the strange effects that can result from using the Q shutter with fast moving subjects. It's similar to focal plane distortion, but the reasons are quite different. Without the shutter in the adapter fast moving objects will distort.

It's a beautiful piece of kit and. holding it and looking closely at it, it's quite clear that £199 is justified and £50 would be an unrealistic expectation.

Flatness of field relates to a lens projecting an image onto a flat surface. A lens with a flat field, such as a macro lens, will give an image of flat subjects that are sharp from centre to edge.

A lens with field curvature will give images sharp in the centre but not the edge, or vice versa. Lenses naturally have field curvature, so it has to be corrected by good lens design. This is much more difficult with fast, wide aperture lenses.

Hope that helps!

The different lenses have different characteristics, being intended for different purposes.

The f/1.4 is a low light and reportage lens, so has high contrast and lower resolution. It's ideal for newspaper and magazine reproduction. It is unlikely to have a flat field at close distances, so is less suitable for close ups.

The f/1.7 will have higher resolution and a flatter field. It is more suitable for close ups and attaching to bellows and fitting close up lenses. In other words, it can take more optical abuse and still deliver the goods.

I would use both for now, much more intensively, and eventually you will find out for sure which one meets your needs best.

The Q7 has a slightly larger sensor, so the magnification factor will be slightly less. That is, the field of view is wider with any given lens.

There's not much in it.

There will always be open days and small exhibitions around the country, but the logical place for easy access for all seems to be the NEC. Half way from everywhere, close to nowhere....

B&H don't seem to be a great indication of what is or isn't discontinued. We've bee here before, with them marking products thus and then finding supplies are still plentiful elsewhere.

I suppose there are different degrees of "discontinued". Even at the factory items will be made in batches, so it's only discontinued when irrevocably the tooling has worn out and there's a decision made never to make any more. Or the product has been updated, making the last one redundant.

Or "discontinued" in a particular market, as supplies dwindle and no more are ordered for an area.

The FA 50mm f/1.4 is a classic example of a "discontinued" product that seems to have managed to survive in that state for several years so far. I suspect they made some more as demand went up again.

I was having a look at the Pentax adapter at the NEC and it's easy to see why it costs so much more than the Chinese versions.

I have tried the Q with various K lenses and it works very well. However, it takes a bit of practice to nail the focus every time.

The Q7 won't offer quite the same magnification, but should offer improved image quality.

I spent some time with the II and IIs and the K-3 when I reviewed them for ePHOTOzine. Trying to get any moire, especially with the K-3, was next to impossible.

I wouldn't worry about it and would go for the extra bite of the IIs or K-3.

I'll assume you mean dissonance, but let's not be pedantic... I agree that would be a terrible shock, but I'd cope.