[Digitalis]

Obviously, a picture taken with an "AA-filter" requires and tolerates more sharpening.

you have to sharpen every shot taken with a camera equipped with a Bayer AA filter - to counter the blurring caused by it. this doesn't mean that cameras with AA filter have greater sharpening latitude. If you are using a high resolution lens capable of resolving 80Lp/mm and beyond the need for sharpening is reduced.

Can the blurring effect be undone by capture-sharpening without loss of information/details? What and how to compare?

Capture sharpening can only increase the accutance of details already in the image - those details lost to AA filter blurring, camera shake, or by simply being out of focus can not be recovered. De-convolution software does exist, however from what I have seen it isn't very effective.

What is the variance in using different samples of the same lens

The best and only way to test two cameras is to use the same lens, preferably a Prime lens with a focal length around 35-100mm, and if you use an aperture below the diffraction limit the differences between the K5 and K5IIs will be clearer - Both cameras have the same resolution, however details at or approaching the Nyquist limit on the K5II will be attenuated by the Bayer AA filter - this does not happen with the K5IIs

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Last edited by Digitalis; 03-05-2013 at 11:11 PM.

[Chris Mak]

More subtlety to the theme and some questions to answer:

1. What is the purpose of trying to prove, that the filterless K5IIs does not produce images with more detail, or that the same detail can also be achieved with capture sharpening/deconvolution/de-blurring, if you do not have any intention of ever buying one?
   
   -looking for ways to bide your time until the k3 is released
   -can't stand the thought that the k5 may not be the best pentax camera around anymore
   
   
2. Should people be upset if an "AA-filterless" camera is sharper?
   
   normally not, but you should be if you:
   -hate pixel peepers that hunt for superior detail at 100%
   -hunt for moire or false colors at 100% yourself all the time
   
   
3. What and how to compare, and are K5IIs owners, and non-owners on equal footing?
   
   not counting those that only just received the K5IIs (they may suffer from seeing it all a bit tóó rosy)
   -owners have a simple benefit: they actually háve the camera that they are judging
   
   
4. How subtle is the difference?
   
   -related to the measure charts: it appears somewhere around 8%
   -related to the satisfaction of users: it appears to be substantially higher.
   
   
5. What about noise?
   
   does the K5IIs generate a lot of noise?
   -in the fora, yes, lots of noise
   -in the images, less than the k5, particularly at 400/800 iso
6. ...

[Digitalis]

What about noise?

This is a bit subjective, but in essence the K5IIs and K5II produce identical amounts of noise - if you excuse the pun, the K5IIs has an edge over the K5II because it doesn't have a Bayer AA filter, so on the K5IIs next to no sharpening is needed* for optimal output. I consider the ISO limit(for me) on the K5IIs to be ISO 12800, that is as far as I am willing to push things on the K5IIs - On my Nikon D4 my limit is ISO 25600.

* Sharpening always makes noise much more apparent,especially luminance noise. There are selective sharpening techniques that can be used as well as noise removal software - but there is a price to be paid by using either method.

[Anvh]

Capture sharpening can only increase the accutance of details already in the image - those details lost to AA filter blurring, camera shake, or by simply being out of focus can not be recovered. De-convolution software does exist, however from what I have seen it isn't very effective.

How much does the filter actually blur?
If we assume it blurs 1 pixel then actually most if not all of the detail can still be captured with a real world colour image instead of a black and white target.
We are working with a bayer filter after all so of the 4 pixels 2 capture green, 1 blue and 1 red. If we shoot a red target then we are roughyl using only 1/4th of the pixels anyway so a blur of 1 pixel will not effect the details there in significant way.

[froeschle]

A remark on comparing JPGs and RAWs with the same settings:

German ColorFoto (1/2013) wrote that Pentax trimmed the K-5 II(s) to deliver more contrasty images (at least up to ISO 1600).
Standard signal processing was found to be more aggressive compared to previous models (like the K-5).
Some speculate that even RAW files might be affected.
So, the same settings will not guarantee the same image processing (when e.g. comparing K-5 and K-5 II images).
The same might be true in a comparison between the K-5 II and the K-5 IIs (the firmware also differs).

you have to sharpen every shot taken with a camera equipped with a Bayer AA filter - to counter the blurring caused by it. this doesn't mean that cameras with AA filter have greater sharpening latitude. If you are using a high resolution lens capable of resolving 80Lp/mm and beyond the need for sharpening is reduced.

Probably, the output from all cameras will profit from some sharpening.
However, the optimal parameters won't be the same.
The "magnitude" for the K-5 II would be higher than that for the K-5 IIs (and could result in an over-sharpened image there).
In this sense, the latitude (to apply a reasonable amount of sharpening) differs.
Using a "better" lens might also increase sharpness to more desirable levels.
So, for a meaningful comparison, one should choose a reasonable starting point:
Choose optimal - and therefore different - settings for both cameras.
The relevant differences may be revealed after this procedure.
This approach might affect e.g. noise as you assert that

[...] Sharpening always makes noise much more apparent [...]

However, there are additional aspects:
The birefringent crystals do not only "blur" the picture, they also have (frequency dependent) optical properties.
These could also modify the final picture.
Some claim that e.g. PF, CA and UV/IR properties change in a noteable way.

[...] those details lost to AA filter blurring, camera shake, or by simply being out of focus can not be recovered. [...] details at or approaching the Nyquist limit on the K5II will be attenuated by the Bayer AA filter - this does not happen with the K5IIs [...]

The question is: Which and how much information is lost - if at all.
Do MTF values drop markedly before the Nyquist limit?
How "strong" is the "AA-filter" in the K-5 (II)?

[...] The best and only way to test two cameras is to use the same lens [...]

Agreed. The purpose of the question ("What is the variance in using different samples of the same lens") was to classify the result of "8%".

1. What is the purpose of trying to prove, that the filterless K5IIs does not produce images with more detail, or that the same detail can also be achieved with capture sharpening/deconvolution/de-blurring, if you do not have any intention of ever buying one?
   
   -looking for ways to bide your time until the k3 is released
   -can't stand the thought that the k5 may not be the best pentax camera around anymore
   
   
2. Should people be upset if an "AA-filterless" camera is sharper?
   
   normally not, but you should be if you:
   -hate pixel peepers that hunt for superior detail at 100%
   -hunt for moire or false colors at 100% yourself all the time
   
   
3. What and how to compare, and are K5IIs owners, and non-owners on equal footing?
   
   not counting those that only just received the K5IIs (they may suffer from seeing it all a bit tóó rosy)
   -owners have a simple benefit: they actually háve the camera that they are judging
   
   
4. How subtle is the difference?
   
   -related to the measure charts: it appears somewhere around 8%
   -related to the satisfaction of users: it appears to be substantially higher.
   
   
5. What about noise?
   
   does the K5IIs generate a lot of noise?
   -in the fora, yes, lots of noise
   -in the images, less than the k5, particularly at 400/800 iso
6. ...

The thread is devoted to the comparison between the K-5 II and the K-5 IIs.
The question is posed whether image quality differs significantly.
What I dislike(d) in this context are unfounded and/or overexagerated statements.

1. Sharpening is required to define a reasonable starting point (see above). More detail could be there (or not).
   A new model with increased number of MPs will most likely be a more significant improvement over the K-5 II than the K-5 IIs [if detail/sharpness/... (=pixel-peeping qualities) are concerned].
   However, the (very similar and very good) image quality of the K-5, the K-5 II and the K-5 IIs will not be altered by this.
   
2. One question is whether and to which amount this ("sharper") really is true. Imho, a lot of exorbitant (maybe even untrue) claims circulate.
   
3. K-5 IIs owners have made their decision and can be happy with it - as K-5, K-5 II, ... owners can be.
   K-5 IIs owners who also possess a K-5 II even could contribute in more detail to the discussion.
   
4. Does the difference scale with the satisfaction of the users?
   
5. According to DxOMark there is no relevant discrepancy between the K-5, the K-5 II and the K-5 IIs.

[Digitalis]

Some claim that e.g. PF, CA and UV/IR properties change in a noticeable way.

that is certainly a valid point, In my comparison against my Pentax K7 the Pentax K5IIs has superior corner sharpness with ultra wide angle lenses, and I also noted improved Image quality when using

The DA15mm f/4 with my hoya R72 IR filter:

100% corner crop - Left - pentax K5IIs Vs Right- Pentax K7

K-5 IIs owners who also possess a K-5 II even could contribute in more detail to the discussion.

That Is part of the problem, many K5IIs owners are reluctant to shell out for a K5II - so comparisons from regular users will be harder to come by. the same goes for the K5 Vs K5IIs - both cameras have the same sensor, sot there isn't much point in buying a K5IIs - Unless a photographer wishes to see what it is like to use a camera without a Bayer AA filter.

However, the optimal parameters won't be the same.

No, they won't. Therein lies the difficulty of comparing the two cameras - Personally I compare the unsharpened output between cameras. because sharpening is a very subjective thing.Personally I prefer people to be able to see what RAW images look like developed straight out of the processing software using default parameters.

According to DxOMark there is no relevant discrepancy between the K-5, the K-5 II and the K-5 IIs.

DxO - they have questionable impartiality, reducing a camera to a two number score where a single digit difference cause pointless arguments over which camera is better.If Dxo couldn't see any difference between the two - they weren't using lenses that were good enough, the DA 18-55mm isn't what I would call a high performance lens.

[Chris Mak]

A remark on comparing JPGs and RAWs with the same settings:

German ColorFoto (1/2013) wrote that Pentax trimmed the K-5 II(s) to deliver more contrasty images (at least up to ISO 1600).
Standard signal processing was found to be more aggressive compared to previous models (like the K-5).
Some speculate that even RAW files might be affected.
So, the same settings will not guarantee the same image processing (when e.g. comparing K-5 and K-5 II images).
The same might be true in a comparison between the K-5 II and the K-5 IIs (the firmware also differs).

How would one speculate as to whether contrast in RAW has increased compared to the original k5?
Only thing I could come up with, would be a tone curve applied to the raw data.
As I shoot only raw, I can not share any thoughts on the jpeg rendering.
In general, I would expect the perceived contrast to be more pronounced with the k5IIs due to the lack of a blurring filter.
Anyhow, if Pentax were to manipulate the Raw data to add contrast to the images, that would be a really dubious step.
As to how "more aggressive signal processing" would be supposed to translate to altered Raw IQ, I have no idea...

The thread is devoted to the comparison between the K-5 II and the K-5 IIs.
The question is posed whether image quality differs significantly.
What I dislike(d) in this context are unfounded and/or overexagerated statements.

My post wasn't really being serious of course, and the removal of the AA-filter is only part of what the K5IIs does better. Better working IS could play a part, reduced mirror shake or better dampening could play a part. Bottom line is, that the K5IIs is still "only" an APSC crop camera with 16mp, and can't be expected to streets ahead of the K5. So over exaggerated statements should be reserved for the Pentax FF or future Apsc releases with considerably higher resolution.
That doesn't take away from the fact that there is a clarity and quality in the K5IIs images, that you will only appreciate if you actually use the camera. IQ is more and more a hard to quantify factor: mostly áll current cameras produce good IQ, raw converters are mostly all very good now.. It will more and more depend on the quality of screen and printer you use at home, the lenses you use, and your own eyes.

1. Sharpening is required to define a reasonable starting point (see above). More detail could be there (or not).
   A new model with increased number of MPs will most likely be a more significant improvement over the K-5 II than the K-5 IIs [if detail/sharpness/... (=pixel-peeping qualities) are concerned].
   However, the (very similar and very good) image quality of the K-5, the K-5 II and the K-5 IIs will not be altered by this.
   
2. One question is whether and to which amount this ("sharper") really is true. Imho, a lot of exorbitant (maybe even untrue) claims circulate.
   
3. K-5 IIs owners have made their decision and can be happy with it - as K-5, K-5 II, ... owners can be.
   K-5 IIs owners who also possess a K-5 II even could contribute in more detail to the discussion.
   
4. Does the difference scale with the satisfaction of the users?
   
5. According to DxOMark there is no relevant discrepancy between the K-5, the K-5 II and the K-5 IIs.

Bottom line for me is: with good lenses you get more clarity an detail out of the K5IIs, it is improved in other areas than only being filterless, compared to the k5. It has no issues (is very dependable). And moire plays no role in general shooting.

[Digitalis]

German ColorFoto (1/2013) wrote that Pentax trimmed the K-5 II(s) to deliver more contrasty images (at least up to ISO 1600). Standard signal processing was found to be more aggressive compared to previous models (like the K-5). Some speculate that even RAW files might be affected.

I would be interested in finding out how they came to this conclusion, since few other people who have reviewed the K5IIs have noticed any anomalies in processing - from my own experience it is in line with other AA filterless cameras I work with - Nikon D800E, Leica S2, Pentax 645D, Leica M8, M9, Leica Monochrom and various Phase One and Leaf Medium format Digital backs.

[Anvh]

A remark on comparing JPGs and RAWs with the same settings:

German ColorFoto (1/2013) wrote that Pentax trimmed the K-5 II(s) to deliver more contrasty images (at least up to ISO 1600).
Standard signal processing was found to be more aggressive compared to previous models (like the K-5).
Some speculate that even RAW files might be affected.
So, the same settings will not guarantee the same image processing (when e.g. comparing K-5 and K-5 II images).
The same might be true in a comparison between the K-5 II and the K-5 IIs (the firmware also differs).

I've also read that the AA filter is actually different as well between the K5 and the MKII version. Haven't seen anything official on this matter though.

[Anvh]

froeschle, you might like this.
https://www.pentaxforums.com/forums/pentax-k-5/207505-pentax-k-5-iis-vs-k-5-ii-take-two.html

[Anvh]

DxO - they have questionable impartiality, reducing a camera to a two number score where a single digit difference cause pointless arguments over which camera is better.If Dxo couldn't see any difference between the two - they weren't using lenses that were good enough, the DA 18-55mm isn't what I would call a high performance lens.

It's actually quite simple why DxO sees no difference, they test things where the AA filter has no effect on.

[froeschle]

superior corner sharpness with ultra wide angle lenses, and I also noted improved Image quality when using [...] The DA15mm f/4 with my hoya R72 IR filter

This difference should only be caused by the (lack of an) "AA-filter"?
This would be an interesting (IR) effect.
Have you checked that with other ultra wide angle lenses?
Is the image equally sharp in the middle of the picture?
Is transmission (exposure time) changed?
Due to e.g. field curvature, do you rate the DA 15 at open aperture as an adequate performer?
Pentax SMC-DA 15mm f/4 AL ED Limited - Review / Test Report - Analysis

they weren't using lenses that were good enough

Wouldn't all lenses profit from the lack of the "AA-filter" (see post #1, #37).

I prefer people to be able to see what RAW images look like developed straight out of the processing software using default parameters.

This approach obviously will favour the filterless versions.
Data from cameras with "AA-filter" will not optimally be processed.

How would one speculate as to whether contrast in RAW has increased compared to the original k5?

Speculation and my point rather is, whether RAW is really as RAW as many suppose.
NR already is applied to RAW files in e.g. the Pentax Q:
DxOMark - A quality review of the Pentax Q

We found a very strong smoothing for the Pentax Q for all ISOs. To put the Pentax Q on the same footing as its competitors, we estimated the noise levels before smoothing, and it is these “pre-smoothed” noise estimates that we use in our comparisons.

ColorFoto indicated that at least the JPG output is nowadays more actively tuned by Pentax - even in the standard settings.

froeschle, you might like this.

Thanks. But I see some "color problems" in these images, which are not present there: K-5 IIs vs K-5 II - can you tell the difference?: Pentax SLR Talk Forum: Digital Photography Review
In this thread you will also find a bold statement:

[...] what is lost to moire can never be regained, though what is obfuscated by the AA filter seems easily recoverable [...]

Dxo couldn't see any difference between the two

My comment belonged to question 5: What about noise?
And "DxOMark Camera Sensor is all about noise": DxOMark Camera Sensor

[Digitalis]

This difference should only be caused by the (lack of an) "AA-filter"? This would be an interesting (IR) effect. Have you checked that with other ultra wide angle lenses? Is the image equally sharp in the middle of the picture? Is transmission (exposure time) changed? Due to e.g. field curvature, do you rate the DA 15 at open aperture as an adequate performer? Pentax SMC-DA 15mm f/4 AL ED Limited - Review / Test Report - Analysis

from what I understand about birefringent materials is that they often have different optical characteristics depending on the frequencies of light passing through them, with the removal of the Bayer AA filter IR performance of a number of lenses is improved - however in contrast to the K7 the K5IIs has significantly reduced red/IR sensitivity. I have also noted that there is a reduction in hot-spotting with certain lenses on the K5IIs with the Hoya R72 filter. The reason for the reduced IR sensitivity is because of the sensors large dynamic range where IR contamination would be visible if they didn't use a strong UV/IR cut filter. I have compared the performance of the DA15mm f/4 ED ASPH limited to the Sigma 8-16mm f/4.5-5.6 ASPH DG:


100% crop extreme top-left, Unsharpened.

While the central resolution of the DA15mm f/4 enjoys a considerable improvement in IQ on the K5IIs over cameras equipped with the Bayer AA filter, resolution is impressively high in the centre but the corner sharpness at f/4 is simply atrocious. this is a characteristic that is common in portrait lenses, but not wide angle lenses, which are less than ideal for such applications. I would only use f/4 on the DA15 when I simply had no other choice. Things improve at f/8:


Un-sharpened 100% crops from the extreme top left from each lens.

The sigma 8-16mm f/4.5-5.6 although being a slower lens holds a significant advantage in image quality compared to the DA15mm f/4 ED ASPH Limited- however the DA15 can be used with filters, it is physically lighter and smaller and possesses superior flare tolerance than the Sigma 8-16mm lens. The field curvature of the DA15mm f/4 ED ASPH Limited necessitates the use of Live view when focusing, because if you simply focus the lens without compensating for the field curvature - even at f/8 this can drastically reduce corner sharpness.

[froeschle]

Lenses for photography normally are not optimized for IR applications.
Outside the visible spectrum [A] e.g. the focal plane changes and the quality of the image suffers.
Additionally, flare and hotspots might become an issue.
The weakness of lenses may become more apparent as the wavelength of the light increases.

[...] in contrast to the K7 the K5IIs has significantly reduced red/IR sensitivity [...] a reduction in hot-spotting [...] a strong UV/IR cut filter [...]

The light transmission of the R72 filter is 50% at 720 nm [B].
So, some tail of the visible light will still form the final image (the viewfinder is not totally black).
Electromagnetic radiation further into the IR region will also travel through the lens and possibly cause the above mentioned problems.
A strong UV/IR cut filter now blocks light with such "problematic" wavelengths [C].
Red/IR sensitivity is reduced and only "less critical" light is captured.
This explains why image quality can be increased and hotspots may disappear.
So, without further knowledge, I would attribute this effect to the presence of a strong UV/IR cut filter.

A fancy frequency dependent influence of the "AA-filter" could be checked by directly comparing the K-5 II and the K-5 IIs (if they use the same UV/IR cut filter).
Until further evidence in this direction, I prefer the explanation above.

[A] Visible spectrum: http://upload.wikimedia.org/wikipedia/commons/thumb/f/f1/EM_spectrum.svg/787...ectrum.svg.png
[B] R72: http://diglloyd.com/articles/Filters/spectral/Hoya_R72-8deg.png
[C] UV-IR cut filter (for on-lens applications): http://www.2filter.com/prices/B+W_filters/uv-ir_cut_filter.jpg

[cadart]

Wow. I hope people who are just starting to delve into the super magic fun of photography don't stumble across this thread.