The red lights do indeed just indicate where the camera is focusing. It's all explained in the manual.....

No, it's just the same. The green hexagon indicates that the camera has found focus.

The centre point flashing does not indicate in focus, it is the green heagon that indicates in focus. This seems to be quite a common misconception as it crops up from time to time on the forum.

I don't think we do - the response is linear. However, if the exposure is very long we may start to get noise as the sensor heats up.

There's nothing wrong with the shot as such, but 1/200s is a bit slow for the 300mm, and indeed for the bird, which is also moving. The crop is also not helping.

I would do a more controlled test using a target such as a newspaper taped to a wall. With a tripod and trying every aperture see whether or not the reproduction is good. A still subject is necessary to discern whether or not your point of focus is accurate.

In the case of negative materials, yes, over- rather than under-exposure. Of course correct exposure is the aim, but erring on the side of over-exposure yirelds better negatives.

In the case of reversal (transparency/slide) film the reverse is true. Never over-expose even a touch as this will ruin the result. Many people would under-expose by half a stop as routine. this meant no burnt out highlights and deeper, richer colours.

It reduces aperture like a Waterhouse stop would, in the case of the finger by obscuring half of the field of the lens. As I'm short sighted I can actually do this and see the effect. Look at a distant landscape and place the finger near the eye and along the edge distant objects will become less blurred.

I think you (and myself too until I realised) have been puzzled by the common references to C----n and similar things. I suspect now it is done either (a) as a tongue-in-cheek but not unfriendly metaphorical wink or (b) in the belief that it will reduce the chance of bots picking up the reference and imeediately skewing the adverts towards those marques mentioned.

Personally, I have nothing against other marques and have used most if not all of them, if I hadn't I wouldn't know that I preferred Pentax. Which of course is why I'm here on Pentax User and not somewhere else such as Nikon User, which I guess must exist in some form or another.

It would be very difficult to improve on some aspects of pentax images, especially the superb colour rendition. I have no complaints about image quality whatsoever.

However, there is one dramatic area of improvement and that lies in the vastly improved noise control on the K-5. A different level of performance completely.

I would imagine that the SMC coating has been steadily developed and refined over the years. It may also change when used with different types of glass.

It does appear to be highly effective though, even with complex zoom lenses with umpteen elements.