But based on this apparent principle of 'ever decreasing returns' as we reach into higher bit depths, can you really expect your '2 stops worth' even if you get 16bit?

This highlights the hazards involved in shooting JPEG and leaving the processing to the camera. I have never seen much discussion or advice given here on two apparently critical subjects - 1) how to take proper control of the JPEG output from Pentax DSLRs, and 2) how to practically manage this fine control when out in the field and incorporate it all into the normal shooting process.

I'm glad you raised the matter - I think there should be more discussion and advice here on the issue of how to get the best out of Pentax cameras. Certainly as far as keeping full control over in-camera JPEG processing I think there is a lot more discussion needed, most definately to offer good advice to those new to Pentax and wanting to get the most from the camera.

But, then again, my own advice to them would still be ' RAW RAW RAW' !

I suppose these extra 'bits' should have an impact at both ends of the scale. So can we low ISO shooters look forward to increased visable detail in ever incresing extremes of shadow / highlights as technology advances, without needing to use HDR?

Incidently, I have read that the jump from 8bit (eg shooting JPEG or using a traditional compact) to 12bit (eg K7) provides the most significant quality increase - that the jump to 14bit is not so significant, or even not discernable. I can only assume this is considering the low ISO performance primarily, as I have seen here plenty of testimony to the K5s superiority at high ISO.

Cabstar wrote : 'this could be easily solved by using a polarising filter.'

No doubt that would help - also the glare must make it difficult to assess the colours, both directly on the subject, and especially on the rear LCD. If we are to accept that in-camera JPEG processing is a valid means to achieve consistent quality output with full photographer control, then it must be said that this control can only be applied by continuously referring to the LCD while out shooting.

Even if we actually had the controls required on the camera menu (we don't) then this is an insumountable challenge I contend.

Regarding the polariser - there is a very effective software polariser in Sagelight 4.4, which can be applied to very fine degress and it's effect precisely applied to varying amounts over the image using an 'undo brush' feature, which uses a hidden layer mask (ie not directly managed by the user) to easily control the effect.

Yes, I can see that this 'PRIME' processor is clearly efficient at creating the file in the minimal time required - after all the cameras can shoot in continuous mode up to 7fps - imagine all the processing needed during that!

I was without a laptop for a while last year, and I experimented with using the in-camera RAW processing options - I chose to output to TIFF (but this is only 8bit). So I had my RAW files archived as well as the camera processed TIFFs. I was unable to produce anything like the quality I was getting from PDCU (to 16 bit TIFF) with the camera produced TIFFs - colours were tricky, and textures I found to be blotchy and full of noisey - like interference. I could see the difference at a range of view settings.

Back to the specific problem of the OP - he is not happy with the quality of colours. What he is actually experiencing is poor quality processing - from his camera. I have not seen any specific advice about particular adjustments he could make on the camera to improve it - ie custom image parameters. In fact, we just don't have sufficient fine control over colours on the camera that would be much help here. And in any case, trying to make these adjustments on the shoot, out in the sun, is really wasting time.

I believe that the best advice for someone experiencing this issue and with an obvious interest in quality, is to switch to RAW - forget the in - camera controls except for those that will provide a useful rendering of the image on the LCD for instant feedback - and use a program like PDCU to give you a 16bit TIFF as a starting point. You will find the 'Colour Fine Control' tab can work wonders on individual tones with no quality loss.

John, in relation to the processing times, PDCU takes an age to process a RAW (I mean the actual outputting computing process) compared to a camera processed JPEG. Other RAW converters I have used do also take probably hundreds to thousands of more time units to process than the camera, and this is all on an A10 quad-core machine. There must be a huge amount of extra stuff going on there - it cannot just be innefficient use of computer resources or wasted processes surely?

I don't see that I am exaggerating these differences. And the camera has a tiny brain compared to the computer and program capabilities. Surely it is logical that the output potential from the computer / software combination would be vastly superior?

I have been interested (as mostly a 'low iso' shooter) in understanding what likely benefits there would automatically be at the lower ISO settings on a camera with 'improved high ISO performance'. I'm sure a lot of landscape & architectural shooters would be disappointed to think that the technology for them has 'matured', and is not going to increase much.

It is frustrating that camera makers never emphasise any improvements to quality at low iso setings - I wonder if this is because there truely is no such improvement as cameras develop now, or just that the marketing emphasis is always about 'Low Light performance' ?

As I said, I didn't want to reignite the RAW / JPEG debate, but its difficult to avoid it here. John and Pentaxophile, I believe you are saying that when we reduce an image down to its final printed form, for practical purposes (ie viewing the print from a normal distance) then the difference is minimal.I can accept this to a point - only as far as where the shooting conditions, dynamic range and the scenes colours and tones were within the boundaries that we could expect an in-camera processor to cope with in the microseconds it has to process the shot.

The OP has complained about colours, therefore he is concerned about quality and is looking towards an 'optimised' output (ie he is not accepting of compromise). In my opinion, with DSLRs, an 'optimised' workflow is incompatable with JPEG shooting. The compromise is there from the start, and there's no going back.

If it were true that there was no noticable difference betwen the two posible camera outputs (8 bit JPEG / 12-14 bit RAW) then what is the significance of the enourmous amount of data that is discarded during the 8bit operation? Why bother to capture it then? Don't we buy our cameras with the intention of getting out of them the most they are capable of?

The 'nasty things' I referred to above is not only apparent at the 'pixel peeping' level - it affects the shot's potential on many levels, eg: how much noise reduction will be needed for a smooth sky texture, how much detailing is possible on brickwork or foliage (which translates to potential output sharpening and therefore the largest print you could make)

The reduction to 8bit and the associated data loss will also significantly affect the colour gamut, and therefore the latitute within each colour zone for fine control - exactly what the OP really needs to have much more of at his disposal.

I risk reigniting various ongoing 'RAW vs JPG' debates here but I think it is important - the idea that JPEGS from the camera somehow represent 'no processing' is misleading. In reality, what they represent is in fact a great deal of processing, including WB, hue / saturation, colour vibrancy and toning, and (if needed, such as in the OP shots) a compression of the dynamic range). And all of this processing is being carried out on a tiny camera CPU within microseconds, using various preprogrammed algorithms outside of the photographers control.

The output JPEG represents a file compression and bit depth reduction down to 8 bit (from 12 or 14 bit data created by the sensor which is then simply deleted from the camera memory). Its true that eventually in any workflow we will probably end up creating an 8 bit jpeg, but that is after the opportunity to carry out all the key, quality-critical adjustments on a RAW file or 16bit TIFF, retaining all the extra editing latitude and smooth toning possibilities that allows.

I know RAW processing is not something that everyone wants to get into - but the reality IMO is that if you have any interest in using your camera at its potential and seeing what it has been designed to do, then you have no choice.

Just take a close look at some fine detail from a camera output JPEG (or camera processed 8bit TIFF) and compare to the same image from RAW with basic conversion parameters applied, then output to 16 bit TIFF. I have seen on the 8 bit files some very nasty things!

Nice shot. But what camera controlled custom settings were you using, and how did you keep such a tight grip on any yellow colour noise in those blacks??