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02-19-2010, 11:00 AM   #16
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QuoteOriginally posted by GeneV Quote
How can one tell if the problem is with NR or the jpeg engine or both?
Well, no way of telling for us for sure -
but since the image with no noise reduction does not show red problems (K-x ISO1600 shot with Noise Reduction Off) - I would guess that it's probably not the JPG compression, but the way Pentax are doing the noise reduction?

However in practical terms there is obviously a problem if one sees or are concerned with it.

Let's use two simple examples

1) say one shoots and processes in RAW with very little noise reduction - so on the screen in the RAW editor the reds are fine.

Then because the pic is needed to be posted on the web with limited space - a fairly high compression JPG is used -
then the resultant image probably will have problems in Red - as shown above.

2) start with a normal default JPG from either the K-x or K7 at ISO1600 - do all the necessary processing - but because we're concerned with the quality in Red save to a very high quality (low compression) JPG - however since the image had problems in Red to begin with, a high quality JPG cannot restore Red details - so again the image has red problems.

In either case a viewer is not going to know the difference - if they noticed it at all. However as we know the end result is that there is some problem in Red.

Case (1) shows that even if one shoots and processes inn RAW if the JPG engine saving the file is weak in Red all that extra hard work would be for nothing. eg: if I shot and processed RAW with little or no noise reduction but finished in my normal editor PhotoImpact and saved using its JPG engine even if I used a fairly good quality - the resultant Red would have some problems. My alternative would be to use PhotoShop Elements 7 which seems to do better with Red

(however in mitigation for PhotoImpact 8 check the file sizes PSE=10 is 16Kb, PSE=4 is 4Kb - but PI=75% is 4.2K - no wonder the reds are "better" in PSE!)

Here's a the same crop comparison between PSE=10, PI=100%, and PSE=4


The PhotoImpact image is 19Kb and it is definitely better than the PSE=4 image and looks as good as the PSE=10 image -
so perhaps the PhotoImpact 8 JPG engine is not so bad afterall - it's just that its JPG Quality rating in % terms is not very informative and one has to use a much higher indicated quality
(** note: previously I had posted crops from PSE direct - but these contained metadata which made the files larger I used JPG Cleaner and stripped the metadata out and the files are now smaller PSE=10 is 15Kb and PSE=4 is 4kB)

QuoteOriginally posted by GeneV Quote
The beauty of the K-x to me is that at 1600, shots are amazingly clean right off the sensor. It is too bad if the jpeg engine mucks it up.
I'd agree with you - but other than shooting RAW - one can quite simply turn the noise reduction Off and get an image ready to use without additional processing - and its file size will be some 3 to 5 times smaller - less space on the hard drive, and less to backup......less processing.


Last edited by UnknownVT; 02-19-2010 at 11:50 AM. Reason: typos, stripped metadata in PSE JPGs
02-19-2010, 11:14 AM   #17
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I'm the guy who was looking for a K-X kit with prime. I like meticulous methodical and patient photography. RAW sounds like a good fit for me then anyway. So here's a new part of the beginner's tutorial I'll have to bone up on. I'll head off to Googleland in a sec. But I'll ask here right off the bat since it's relevant to the thread and I'd like to know how it applies to the K-X specifically. Just skip anything too youthful, exuberant, or otherwise impertinant.

What are the pros and cons of shooting RAW with the K-X? Is this a good place to start? http://digital-photography-school.com/raw-vs-jpeg

Are there shooting situations that make it more or less advantageous considering the pros and cons? (i do understand that raw is a bigger file and may affect burst speed, memory space, etc.)

Is the NR on the K-X a discrete function? Turn it off or on when desired without affecting other processing? Is it something that can be 'tweaked' with improved firmware?

In shooting raw, is batch processing it on your laptop pretty much defeating the purpose? The firmware in the K-X for image processing is just being substituted by another software program of your choice, no? So you're generally going to shoot RAW intent on processing each image individually? Can you get improved/different firmware for the K-X if the original is not to your liking or found to be lacking?

And one more volley in the CMOS CCD debate (oh hell, he's gone too far)? Someone lost his K-X in a cab and discovered that he was happily reacquainted with the images from his older camera. Someone suggested that it was likely due to the fact that the other camera used a CCD sensor. This sounded very similar to comments one hears in hi-fidelity discussions when someone 'rediscovers' their old tubesets. Vacuum tubes (so the argument goes) introduce colorations that are more pleasing, though less comparatively accurate, than the cleaner signals through solid state components. Similarly between vinyl/analog and digital. Actually, since the CCD is outputting analog and the CMOS is outputting digital, the analogy between vinyl and digital CDs might be more appropriate. And likewise you hear people saying that analog is purer and more 'pleasing'. Digital adherants generally counter with the claim to accuracy. Any of that at all relevant to the CMOS vs CCD, K-X vs K100 question?

Is it possible that if 'noise' control is a very high priorty in your images that the CCD is advantageous enough (in 2010) to pass on the CMOS for a while when deciding on a new purchase? Is this really nitpicking? The original question in this thread seems to have touched some kind of nerve anyway.

Last edited by frascati; 02-19-2010 at 11:50 AM.
02-20-2010, 04:30 PM   #18
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QuoteOriginally posted by frascati Quote
What are the pros and cons of shooting RAW with the K-X?
Same as with an camera. Pro: more latitude for post processing. Cons: bigger files, slower processing times.

QuoteQuote:
Is this a good place to start? RAW vs. JPEG
Looks really simplistic. There is much better information in the hudnreds existing threads on the subject right here on pentaxforums, so I suggest you start by looking at some of those.

QuoteQuote:
Is the NR on the K-X a discrete function? Turn it off or on when desired without affecting other processing? Is it something that can be 'tweaked' with improved firmware?
Yes, yes, and yes.

QuoteQuote:
In shooting raw, is batch processing it on your laptop pretty much defeating the purpose?
Not at all. The point of shooting RAW is to give you more exposure for PP *when you need it*. For the shots that don't need it, there's nothing wrong with batch processing.

QuoteQuote:
Can you get improved/different firmware for the K-X if the original is not to your liking or found to be lacking?
No, but that's also just not an issue in practice. It's like hesitating before buying answer car to ask if it's possible to download new firmware for the engine control system because some random reviewer who really doesn't know what he's talking about thinks the car shifted from 2nd to 3rd gear sooner than he thought it should and therefore 0.003% worse mileage than it should.

QuoteQuote:
And one more volley in the CMOS CCD debate (oh hell, he's gone too far)?
Yes. There are maybe 17 people on this planet who can reliably tell the difference between an image shot with CCD versus one shot with CMOS. You are *not* one of those people.
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