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12-31-2011, 08:55 AM   #1
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Default NR too strong - destroying detail?

I've just acquired a K5, having used a Samsung GX-10 for several years, latterly with a couple of Pentax-A and -M lenses which gave me some lovely images, but which wasn't great above ISO 400-800 and had poor autofocus and only OK metering. I was really looking forward to the low noise / high ISO ability of the K5, as I prefer natural light shots most of the time. I've also just invested quite a lot in some more lenses (Sigma 105 Macro, 35 Ltd macro, and Pentax 12-24 (yet to arrive) so am quite keen to see the benefit of the upgrades.
I was initially very concerned at the 'mushiness' of detail in the K5 images - my wife has fantastic golden hair which is a great resolution test, and this was coming out terribly even at ISO400. See first two examples below (Pentax 55-300 @ 55, flash 1/180s, and then 35Ltd Macro :-) also at ISO400). Even the RAW versions were little better.

I did some focus adjustments with various lenses, and whilst this was successful in addressing some errors (front focus mostly), I was still not seeing the contrast and edge clarity that I expected, and some edge-associated JPEG artefacts were horribly obvious - looked like a point and shoot shot. A friend's Canon 5DII was in a completely different league, under the same (poor) lighting conditions.
I have checked for 'black' noise by making 1sec exposures with the lens cap on at different ISOs, using ImageJ to produce histograms of each RGB channel's values in the resulting JPG - there is a systematic and reasonable variation, with very little noise apparent - but this is on the NR-treated JPGs so perhaps not a good index. I'll have to find a way to get the full 14-bit values from the RAW files - any suggestions?

Before I update the firmware, which may alter the results, I have turned off NR completely, and this has made a substantial improvement - rather a relief, but it's concerning that such a negative impression of the camera's quality can be had using the default settings.
Without NR, things are much better: even at ISO3200 a 100% crop is just a little noisy but without the mangling of all detail that was happening before. The second pair of hair samples below are at 800 and 3200 ISO, using the Sigma105 macro. Much preferable, although the RAWs may yet deliver something even smoother and more natural looking.

It seems that this is a solved problem, but I wanted to ask anyone with more experience and knowledge whether this has been a known issue with the default settings, whether the newer firmwares are better behaved, and what optimum settings for NR vs ISO might look like. I had worried that my K5 was defective in some subtle way (poor a/d, whatever) but my worries are receding - any confirmation that all is well would be very welcome! I hadn't seen this question discussed despite my extensive reading-around before getting the K5. I'm going to update the firmware and re-calibrate the lenses next...

cheers to all, happy new year!

Miles

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12-31-2011, 09:13 AM   #2
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We performed a hish-ISO NR test in our k5 review, and it's evident that the lack of noise comes at the expense of detail, although the camera does a pretty good job of it:
Pentax K-5 Review - Image Tests - PentaxForums.com

You'll almost always get the best results by shooting raw and disabling all in-camera processing, and then applying the noise reduction in post-processing (i.e using the topaz denoise plugin or just photoshop). For everyday shots I don't mind what the camera does, though

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12-31-2011, 11:35 AM   #3
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Adam, many thanks for confirming that this is the way to go - I will cautiously reintroduce in-camera NR for the higher ISOs and see what I can get - I don't always want to do a full RAW conversion just to get a basic image. I'm on Linux so PS and ACR are not available, I have to use UFRaw and others - and I'm still learning how to get the results I want from these. Denoising and sharpening have to be done carefully! It's been a while since a review of the Linux workflow options, perhaps there's a good opportunity to combine a processing guru and a linux user to make an up to date tutorial.

I've now done the update to firmware v1.11, and have redone the microadjustments for each lens - all are now showing me much more of the clarity that I was hoping for when pixel peeping, and the metering/focusing is very acceptable. I have noticed a shift in metering and image tone between LV and normal shooting - something to check further. Using the 55-300, the LV image (with 2s delay and same manual exposure) had far less colour fringing than the same shot taken normally. Not sure I understand this one yet either. I also noticed a shift from 1/40s to 1/30s metered exposure between normal and LV mode, when doing focus adjustment shots on a static target. Is this common experience?


Happy New Year.

Miles
12-31-2011, 11:59 AM   #4
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QuoteOriginally posted by MilesWH Quote
I'm on Linux so PS and ACR are not available, I have to use UFRaw and others - and I'm still learning how to get the results I want from these. Denoising and sharpening have to be done carefully! It's been a while since a review of the Linux workflow options, perhaps there's a good opportunity to combine a processing guru and a linux user to make an up to date tutorial.
If you're concerned about maximum sharpness at high(er) ISO, post-processing is probably the way to go, based on my limited time with this camera. (In-camera NR is pretty decent but you'll get happier results with PP.) As far as Linux processing options, good luck -- frankly, you might be better off setting up a Windows double-boot system just to run LR (or something similar).

QuoteOriginally posted by MilesWH Quote
redone the microadjustments for each lens -
Threadjacking a little, but is there a best-practices guide somewhere for how to do this?

12-31-2011, 12:01 PM   #5
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I have also noticed LV metering slightly differently (no wonder really as it uses the image sensor as opposed to the dedicated exposure sensor).
12-31-2011, 01:21 PM   #6
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I have a K-r rather than a K-5, but they should be similar in this regard, expecting a bit more from the K-5. I turned off all noise reduction and other pp settings in my camera within a month of getting it. I also turned off default NR and sharpening in ACR, as I'd rather do that in Photoshop (with dedicated plugins). Default settings are created on the expectation of no post processing. People who want to dump photos off their camera and use them, whatever the quality. I think Pentax (and other brands) expect people who want more out of it to turn these things off for themselves.

So yeah, turn it all off, and enjoy your post processing. You'll find it much better that way.
12-31-2011, 02:05 PM   #7
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The one thing you should note as well is that the k5 has a pretty strong AA filter compared to the k10d (gx10). At 100% crops the k10d images are much shaper and to be honest isn't that far behind the k5 when it comes to resolving detail but when it comes to high iso the k5 simply blows the k10d away.

I have had iso 3200 images shot in raw, pushed +1ev and also lifted the shadows (I shoot raw) and the image still looked very nice on print, I couldn't hope to do this with a k10d.
12-31-2011, 03:30 PM   #8
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Boy am I glad I saw this thread, I had no idea! Turned off high ISO NR and it did make a big difference. I think I'll follow Adam's tip and buy topaz denoise, it has great reviews.

12-31-2011, 04:43 PM   #9
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+1...

QuoteOriginally posted by Philoslothical Quote
I have a K-r rather than a K-5, but they should be similar in this regard, expecting a bit more from the K-5. I turned off all noise reduction and other pp settings in my camera within a month of getting it. I also turned off default NR and sharpening in ACR, as I'd rather do that in Photoshop (with dedicated plugins). Default settings are created on the expectation of no post processing. People who want to dump photos off their camera and use them, whatever the quality. I think Pentax (and other brands) expect people who want more out of it to turn these things off for themselves.

So yeah, turn it all off, and enjoy your post processing. You'll find it much better that way.
+1. I turn everything off and shoot RAW in black & white. I feel that black & white gives me the best idea whether the lighting is correct. If I want color output I bring it back in PP.

Last edited by lammie200; 12-31-2011 at 05:08 PM.
01-01-2012, 04:04 AM   #10
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Thanks a lot for this info. Very helpful.
01-01-2012, 06:03 AM   #11
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Hey, it's good to see that my question has been useful :-) Is there a 'K5 tips' document somewhere that would give new owners a brief walkthrough of any 'gotchas' like this, and perhaps also ideas for reprogramming the buttons etc in ways that others have found useful. The number of options and combinations is a lot to think about, and its easy to miss stuff. The manual is helpful, but puts everything on the same level - a 'top tips' list would be very helpful. Is there such a thing? (I haven't looked at the FAQ - next job I guess!)

The B&W shooting tip is an interesting one - I'll try that out. RAW does allow one to do some really neat stuff!!

Happy New Year to all.

Miles
01-01-2012, 06:20 AM   #12
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QuoteOriginally posted by MilesWH Quote
Hey, it's good to see that my question has been useful :-) Is there a 'K5 tips' document somewhere that would give new owners a brief walkthrough of any 'gotchas' like this, and perhaps also ideas for reprogramming the buttons etc in ways that others have found useful. The number of options and combinations is a lot to think about, and its easy to miss stuff. The manual is helpful, but puts everything on the same level - a 'top tips' list would be very helpful. Is there such a thing? (I haven't looked at the FAQ - next job I guess!)

The B&W shooting tip is an interesting one - I'll try that out. RAW does allow one to do some really neat stuff!!

Happy New Year to all.

Miles

One tip I would give would be to customise your raw/fx button, I use mine to get into sensor shift.. its a great and unused feature imho.
01-01-2012, 07:45 AM   #13
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This thread has become quite an informative one. You just saved a lot of peoples time, those with new K5s over the festive period!
01-01-2012, 08:22 AM   #14
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QuoteOriginally posted by Opethian Quote
This thread has become quite an informative one. You just saved a lot of peoples time, those with new K5s over the festive period!
What all do I need to do to turn off ALL pp?
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