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11-14-2012, 10:48 PM   #106
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QuoteOriginally posted by vonBaloney Quote
Oh, you caught me (I deleted my message). User error -- had my tabs mixed up -- moire is in the IIs version...
No problem, I saw the post was gone after I replied
So what do you think of the detail that can be pulled out of the K-5 II?

11-14-2012, 11:02 PM   #107
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QuoteOriginally posted by JohnBee Quote
No problem, I saw the post was gone after I replied
So what do you think of the detail that can be pulled out of the K-5 II?
Not much between them -- looks good. We had tried the Topaz inFocus (which has deconvolution) but didn't like it (we have most of the other Topaz plug-ins, most of which are great) -- I wonder if it works on the pixel level like that. I'll have to look into raw therapee. Are there particular parameters on the deblur, or is it just a checkbox?
11-14-2012, 11:11 PM   #108
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QuoteOriginally posted by JohnBee Quote
Pentax K-5 IIs vs Pentax K-5 II (with deblurr).
Thanks, John.

One can see that the sharpening for the K-5 II also amplifies the noise a bit, but a) I prefer the K-5 II image as it is and b) one could address that by appropriate masking settings.

N.B., the pink pattern left of the Queen of Hearts card is interesting as it is already destroyed by K-5 IIs moiré but the K-5 II still shows it with all detail. The pattern below it shows some moiré for both cameras, but the K-5 II moiré is subtle in comparison.
11-14-2012, 11:12 PM - 1 Like   #109
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QuoteOriginally posted by vonBaloney Quote
Not much between them -- looks good. We had tried the Topaz inFocus (which has deconvolution) but didn't like it (we have most of the other Topaz plug-ins, most of which are great) -- I wonder if it works on the pixel level like that. I'll have to look into raw therapee. Are there particular parameters on the deblur, or is it just a checkbox?
Actually I did this one using Topaz Detail. Which is perhaps one of the best deblur tools ever made. However, I've used Raw Therapee's option as well which is very close in terms of performance. And you can find that option under Sharpening :> Method: Deconvoluted Sharpening.

However, if you want to avoid Raw Therapee, you can use Topaz Detail's deblur function with the following settings: Strength/18, Radius/68 which is about what's needed to get the K-5 II into the same area of detail as the K-5 IIs at default.

Once you've deblurred the image you can then sharpen it as you would any image, though I've found that both images require different sharpening adjustments to end-up with similar levels of detail. ie. the K-5 IIs is pretty straight forward, though the K-5 II benefits the most from a low or small radius combined with a high sharpening level. I'm guessing this amplifies the remaining microcontrast details left over in the image.

Hope this helps.

PS. I used FocalBlade to sharpen the images because it is the worlds most powerful sharpening tool ever.


Last edited by JohnBee; 11-15-2012 at 12:03 AM.
11-14-2012, 11:27 PM   #110
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QuoteOriginally posted by goldenarrow Quote
You say the blurring effect can be reversed with capture-sharpening. Can you post pictures that demonstrate what you are talking about?
See the post by JohnBee.

QuoteOriginally posted by goldenarrow Quote
What would the theoretical amount of sharpening be with common forms of moire (AA mitigated)?
You may find Falk's (falconeye's) article about Understanding Image Sharpness interesting.

QuoteOriginally posted by goldenarrow Quote
Would one use USM or High Pass Filter or some other magic elixer???
The best approach would be an image filter that uses a theoretical model of an Bayer-AA-filter and tries to undo it. A deconvolution filter with the correct strength settings should do the job. But other sharpening methods will produce very good results as well. One can even imagine multi-pass sharpening, using different settings in different phases. After all, most users are after images that "look good" as opposed to reconstructing reality with optimal precision.

QuoteOriginally posted by kh1234567890 Quote
One thing that I am puzzled by is the 'weak' AA filter. What advantage are you gaining by not matching the birefringent image offset to the sensel spacing, if that is indeed what is happening ?
Adding to Falk's great response, I'd like to point out that anything between a "full strength" and a non-existing Bayer-AA-filter is a compromise. A compromise between eliminating moiré (plus other image artefacts) and losing spatial information.

The Bayer matrix is cleverly designed because it captures colour information and spatial information at the same time. A Foveon sensor of the same size with the same amount of sensels captures the same colour information but less spatial information. A good demosaicing algorithm can reconstruct spatial information (i.e,. image detail) from incomplete information. The weaker the Bayer-AA-filter, the better the chances of reconstructing image detail that was actually present. At the same time, however, the likelihood of reconstructing that was never part of the scene and producing image artefacts increases as well.

Designing the strength of an Bayer-AA-filter requires judgement as to what level of image artefacts you are happy to see in what percentage of shots.

I feel that the K-5 (II) Bayer-AA-filters are not "too strong" since these cameras still produce moiré in extreme circumstances and show great image detail when capture-sharpening is used (as it should be).
11-15-2012, 03:50 AM   #111
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Of course the real reason for having the AA filter is that it makes jpeg compression easier and faster

Looking at some of the K-5IIs shots posted on Flickr, most of the buyers would have been better off spending the extra cash on a better lens.
11-15-2012, 08:13 PM   #112
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QuoteQuote:
To me, removing an AA-filter is a hack. The better solution is to increase the resolution and keep an AA-filter. This achieves the same resolution advantages without the drawbacks. Of course there are challenges in increasing pixel-pitch, but I'm happy to wait for those to be addressed rather than having "fun" with artefacts from AA-filterless sensors.
This was my first thought when I heard about the K5IIs. It seemed like Pentax was looking for a way to stay relevant at Photokina but didn't have the goods to display a brand new camera. So they tweaked the trusty K5, and produced a gimmicky AA-filterless option. Still, I'm a sucker for sharpness, so I'm intrigued by the K5IIs none-the-less.
11-23-2012, 07:37 PM   #113
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Fantastic article and media!

11-24-2012, 02:20 PM   #114
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QuoteOriginally posted by Class A Quote
See the post by JohnBee.


You may find Falk's (falconeye's) article about Understanding Image Sharpness interesting.


The best approach would be an image filter that uses a theoretical model of an Bayer-AA-filter and tries to undo it. A deconvolution filter with the correct strength settings should do the job. But other sharpening methods will produce very good results as well. One can even imagine multi-pass sharpening, using different settings in different phases. After all, most users are after images that "look good" as opposed to reconstructing reality with optimal precision.


Adding to Falk's great response, I'd like to point out that anything between a "full strength" and a non-existing Bayer-AA-filter is a compromise. A compromise between eliminating moiré (plus other image artefacts) and losing spatial information.

The Bayer matrix is cleverly designed because it captures colour information and spatial information at the same time. A Foveon sensor of the same size with the same amount of sensels captures the same colour information but less spatial information. A good demosaicing algorithm can reconstruct spatial information (i.e,. image detail) from incomplete information. The weaker the Bayer-AA-filter, the better the chances of reconstructing image detail that was actually present. At the same time, however, the likelihood of reconstructing that was never part of the scene and producing image artefacts increases as well.

Designing the strength of an Bayer-AA-filter requires judgement as to what level of image artefacts you are happy to see in what percentage of shots.

I feel that the K-5 (II) Bayer-AA-filters are not "too strong" since these cameras still produce moiré in extreme circumstances and show great image detail when capture-sharpening is used (as it should be).
Thanks, Class A and JohnBee, for the replies. I will study this carefully as my limited understanding of physics allows. The discussion has already found me experimenting with multi-pass sharpening using a combo of High Pass and USM at different radius settings. Interesting that this allows for a more "realistic" look and less of an "oversharpened" look to the resulting image. Deblurr or Raw Therepee deconvolute sounds good to experiment with next.


Last edited by goldenarrow; 11-24-2012 at 02:25 PM. Reason: extra text
12-18-2012, 10:22 PM   #115
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QuoteOriginally posted by normhead Quote
The thought of using a K-5 for weddings somehow makes me shudder. My cousin used to have a wedding business and always shot with hasseys, that's just what good wedding photographers used to do. What is this world coming to?
Norm, I shoot 100% of my weddings with a K-5. Admittedly, most of my colleagues/friends are shooting them at least with FF or MF, but I have never had a situation yet where the resulting images from my K-5 have been a source of disappointment to my clients or not able to server their needs.
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