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Forum: Pentax K-5 & K-5 II
10-01-2012, 09:22 PM
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There are many reasons why moiré does not always rear its ugly head:- The spatial frequencies in the scene are too low.
- The lens is wide open and acts as a low-pass filter.
- The f-ratio is high enough to cause sufficient diffraction.
- The lens is slightly defocused.
- There is motion blur from camera shake or subject movement.
In all these cases it would be better to remove the cause of the problem rather than slightly mitigating its effect by not using an AA filter.
Conversely, if you manage to make all stars align so that image sharpness is optimal, capture sharpening can completely restore any loss in contrast when using an AA filter, while not using an AA filter just makest moiré likely to occur.
Contrary to what is often stated, moiré cannot easily be removed:- It is always a manual process, requiring detailed attention. There is no way to "batch process" images, repairing moiré in an automated manner.
- Information has irrevocably been lost. Some invented information has to replace the ugly moiré patterns and this patching may or may not look good.
In contrast, the capture sharpening required to remove the little loss in contrast caused by AA filters, can be applied globally to an image and thus be made part of a default import setting (e.g. in Lightroom).
Once an appropriate level of capture sharpening has been applied to an image recorded through an AA filter, there is no significant difference to an AA filter-less version. This is a 100% true for images with no blur. Only when images already contain some blur, an AA-filter may actually destroy some resolution.
BTW, "AA filter" is a misnomer for the birefringent plates that are put before imaging sensors. Watch the following demonstration of birefringence.
You Tube
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src="https://www.youtube.com/embed/WdrYRJfiUv0?controls=1" allowfullscreen>
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Bear in mind that a sensor using a Bayer-filter matrix absolutely needs an approach like this (or equivalent) unless you are talking about images with (relatively) low spatial frequencies only.
No doubt sooner or later someone will publish comparative lw/ph resolution figures showing how much more the K-5 IIs resolves compared to the K-5 II.
I'm just hoping that- These figures will be obtained using appropriate levels of capture sharpening respectively, and
- the figures won't be based on B&W patterns and an approach that ignores the false colour that will be produced by an AA-filter less sensor.
The main purpose of an AA filter in front of a Bayer-matrix is to prevent colour-moiré. This slightly impacts on the sensor's ability to resolve the finest B&W patterns (in a situation where you know that the source is B&W and you then can faithfully reconstruct the B&W pattern using RAW data), but in the real world we are typically facing colourful subjects.
A more useful representation of a sensor's resolution capabilities would be measuring colour resolution. With the current B&W patterns, AA filter-less sensors appear to be resolving more detail (partly due to clever demosaicing algorithms) than they actually do, if you look at true colour resolution. In other words, do not believe that any lw/ph figure advantage the K-5 IIs may demonstrate, translates 1:1 into more detail in colour images.
One way of looking at an AA filter-less sensor is to observe that each part of a scene that corresponds to the size of a sensel on the sensor is only seen with one colour. The sensel is colour blind to other colours and hence only records one colour independently of the real spectrum the particular portion of the scene has. The AA filter, however, manages to expose the same portion of the scene to four sensels (which in combination see all colours), making sure that its full colour can be captured.
There is a reason why manufacturers have been equipping DSLR with the cost-adding, precision element called "AA filter".
Falk (falconeye) wrote this:Personally, I consider a sub-100MP camera w/o Bayer-AA filter technically flawed which is and must be sold with a disclaimer. He also has some good things to say about removing AA filters; his bottom line is "The ommission of the Bayer-AA slightly improves many images and massively deteriorates a few. The exact balance depends on the #MP."
IMHO, there are only very few people -- who have full control over their subject matter -- that can truly benefit from an AA filter less camera.
The vast majority is much better served with a complete image forming system.
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Forum: Pentax Q
10-12-2012, 11:40 AM
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Yes, the Q10 has focus peaking for manual focus assist! Here is the video I shot today at the Toronto Exposure Imaging Expo. Big thanks to Dan Savoie from Pentax Canada who provided the pre-production Q10, the Pentax K-Q adapter, the 35mm Macro Ltd., the tripod, and the focusing hand! (Hey, I provided the K-5 and 35mm Macro #2 to film it!)
Pentax Q10 focus peaking w/ PK-Q adapter
Incredible depth-of-field for macro work, even "wide open" at f/2.8 (as shown above). That 35 Limited is the equivalent of a 200mm macro!
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Forum: Pentax News and Rumors
10-09-2012, 05:09 PM
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http://dc.watch.impress.co.jp/docs/news/interview/20121010_564928.html
* aimed direct transfer without putting my own thought or assumption
* hope I would be able to write better English...need practice...
* please feel free to remove if any problem with copy-right.
Interviewer: Mr. Masakazu Honda (H)
From Pentax Japan: Mr. Toshiyuki Kitazawa (K)
SLR user seeks for better IQ
(H)
Looking at the trend of Fotokina2012, there were FF SLR models targeting high-amateur looking for higher IQ. Three manufacturers have announced new models with FF sensors. Some of them are priced under US$2400 to attract wider range of users. How will Pentax be keeping your pace with it?
(K)
First, there is a trend that is moving forward to higher IQ among whole this industry includes manufacturers and consumers. Meantime, mirrorless segment is moving forward to smaller size. Even though there was possibility to bring FF into this segment, it was our conclusion that APS-C should be the utmost size for mirrorless segment.
On the other hand, consumer’s journey for higher IQ is still going on. We well understand consumer is tapping FF for not only higher IQ itself but also the “high quality product producing high IQ”.
Mirrorless segment is important since it is easier to reduce price than SLR. Manufacturers designed new mounts which enhanced wider option in sensor size as well as more freedom in design. There would be many other ways than higher IQ to make it attractive.
However, SLR remains costly due to its mechanism such as mirror system which enables photographer to view actual image when shooting. It is for user who requires higher IQ as well as product quality itself. We are pretty sure those users have been seeking for better IQ even if only slightly. For this reason they would like to move forward to the largest sensor size which their lens-mount system accepts.
The other side of the mentioned above is that smartphone has been invading segment of low-end point & shoot. As the segment piled up by smartphone, the upper segment for hobbyist (enthusiast) started an increased need for higher level of satisfaction. Mid-end P&S with improved IQ pushes high-end P&S to have larger image sensor, then the P&S with larger format pushes interchangeable-lens camera to next level of IQ.
(H)
If consumer is not satisfied with smartphone’s camera and asking a camera for that kind of satisfaction, P&S camera with larger format might be enough for them, wouldn’t it?
(K)
I think what is hard for smartphone to satisfy consumers are dynamic range, high quality lens, and bokeh. P&S with larger format could be an answer to make up these factors. Smaller difference of image format between those P&S and SLR may diminish SLR’s appeal. Hence manufactures are developing low-end SLR with FF as well as FF into the other segments.
Under Advanced Development targeting 2013 or later
(H)
So, in this situation that hobbyists’ cameras are getting full-sized, what kind of action are you going to take?
(K)
First, we are discussing development of FF SLR. We are touching base with a sensor manufacturer and proceeding the process of development towards productization.
When looking only at “developing new SLR” there is no difference between APS-C & FF and we must be able to produce upon acquiring sensor and appropriate developing. However, we understand that we must make “clear” difference from APS-C in terms of IQ and expanding shooting capability when we produce FF. It was a reason why we have been producing almost only DA series lenses that we had been thinking it was difficult to make the “clear” difference.
(H)
You think now you can make the clear difference because you have started the process of developing FF?
(K)
We are currently discussing what kind of difference we should be able to make. In our case, many of FF lenses have already been discontinued and only FA Limited Lenses and some others are available. When we go with FF, we need to line-up new lens line. It is different from the other manufacturers that have been producing FF cameras.
What should we do to re-make lens line-up and make difference from competitors such as Canon, Sony, and Nikon? Not merely producing FF, Rather, how we should be able to create additional value on it. We have been discussing and not concluded yet.
However, as we understand we can’t launch products right after conclusion, we are in parallel developing aside from making marketing story. This is current status.
(H)
Looking at others focusing strong line-up in entry SLR as well as FF segment, I’m feeling that they are a bit retreating in mid-level SLR segment which is your main battle area. What is your forecast?
(K)
I also feel the segment have not really been focused as a whole industry recently. However I don’t believe they retreat from this segment completely. Pentax is also responsible to existing users for continuously pioneering the market and enhance K-Mount system. We must develop a successor of K-5II as well as updating line-up. Our long term strategy is towards FF while short term strategy is increasing line-up in APS-C segment.
(H)
Back to FF sensor, it is Pentax’ brand image that you are good for small & light weight which is good in field, processing images suitable for field, and high IQ thank to w/o AA.
(K)
We are developing towards commercial productization and will definitely launch though, it is the matter of whether it makes sense or not for Pentax to produce similar FF SLR to others and slightly smaller & lighter FF Lenses than others. As to time frame, it is under advanced development towards 2013 or later. You can expect that.
w/o AA Filter is Prescribed Course
(H)
You have the upper segment which is 645D. What kind of different value do you need to create?
(K)
We have developed the 645D to beat FF’s IQ. As you know, the others say their updated FF caught up with medium format, right? They are looking at 645D as their bench mark to improve their FF SLRs.
However, it’s “current model” of 645D. We feel so honored that they are still targeting it as their benchmark but it was launched back in June, 2010. Needless to say we have been developing the successor. We have updated the lens road map and released 90mm F2.8. We will be continuously updating 645D line up more and more.
(H)
I think 645D made a clear brand image of Pentax for “Field Photography”. You have announced K-5IIs. Also the upcoming FF is expected not to have AA. Nikon also launched D800E. As a pioneer to developing inter-changeable lens camera w/o AA, how you see it?
(K)
We were afraid of receiving complaint on moire when we first developed 645D. However, upon shooting in several scenes there were less moire and fake-colors. Looking at feedback from users, we are happy that they are complimenting its IQ rather than the risk of moire and fake-colors.
After shooting, you can see the world which you can’t see through the view-finder. Those users have been weighing the advantage of seeing another world which they had never seen.
After that, in this year, Nikon launched D800E and it is becoming a trend that removing AA for better IQ, or choosing it for other purpose.
(H)
I think one of reasons of the trend is narrower pixel pitch, isn’t it?
(K)
Both deeper understanding on w/o AA among the market and narrower pixel pitch enabled us to launch K-5IIs. We heard from dealers that they are focusing the newly developed AF unit which catches up down to -3EV as well as K-5IIs which doesn’t have AA. We are surprised at more pre-order of K-5IIs than we expected. We expected less orders due to moire and fake-colors.
16M APS-C image sensor has less than 5 micron of pixel pitch which means we can see at 100M sensor depends on performance of back-end such as processing LSI and/or forwarding interface of image data. We heard some sensor-manufacturer has been developing to target 100M sensor. Anyway, since we have much less risk of moire and fake-colors than 12M, I think w/o AA will be a main stream.
(H)
In that trend, have you found further direction as Pentax, good manufacturer for field photography?
(K)
It is a prescribed course for Pentax to go with w/o AA. We will apply this strategy to many other segments. Meantime, we have been developing another technology for even better IQ which has different approach than w/o AA. We are planning to enhance our originality from a new perspective. You can expect that.
Q-Series, a Maverick
(H)
You have announced Q10. What is your forecast on this segment?
(K)
We are developing several lenses because we only had 5 lenses. We will be updating lens line-up in this year through next year. We are sometimes asked “are you going to quit?” It’s is our valuable line-up and we will never quit as well as 645D which are Pentax-Only areas.
It is said that IQ of Q series are not so good due to its sensor size. However, they understand when looking at the actual print-out. It has achieved for printing onto large paper to some extent and foremost we need it for consumer to experience the joyful world of inter-changeable lens. For the other mirrorless segment, it might be hard for a whole system to fit into a bag.
Before all, we understand our promotion for Q-World has not been enough, we must show off to get attention more and more. Q10 is being launched shortly but the successor is already under development. We lined-up 100 colors to get attention at storefront. We would like to continuously get attention to this series as a maverick.
***Correction***
exiting users => existing users
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Forum: Pentax News and Rumors
09-19-2012, 07:53 AM
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Also, when I asked them about the full-frame (even as I was reading the question), everyone couldn't help but smile. People smile when they're hiding something :)
They also said that the FF will NOT be at CP+, but chances were high that we'll see one in 2013. That's not to say that other shinies won't be announced at CP+!
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Forum: Pentax News and Rumors
04-19-2012, 08:24 AM
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Forum: Pentax SLR Lens Discussion
07-16-2011, 06:35 PM
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I thought that those with the big expensive gear might find my research helpful.
Amazon.co.jp still carries a number of items that you can't get elsewhere.
** The rear FA* CPL for the FA* 300/2.8, FA* 600/4 and FA* 250/600/5.6:
Amazon.co.jpF PENTAX ‰~•ÎŒġƒtƒBƒ‹ƒ^[ FA~ (ƒP[ƒX•t) 35184: ‰Ĉ“dEƒJƒƒ‰
At the time of this writing, they are still in stock.
** The official Pentax 112mm SMC protective filter, for the F*/FA* 250-600/5.6, FA* 300/2.8, A* 600/5.6, and A* 300/2.8 :
Amazon.co.jpF PENTAX SMC PFƒtƒBƒ‹ƒ^[ 112ƒ~ƒŠ 35621: ‰Ĉ“dEƒJƒƒ‰
There is also a more reasonably priced multicoated 112mm filter on Amazon US:
Amazon.com: Marumi 112mm 112 MC UV MCUV Multi-Coated Filter Japan NEW: Camera & Photo
** The official Pentax 145mm SMC protective filter for the A* 400/2.8:
Amazon.co.jpF PENTAX SMC PFƒtƒBƒ‹ƒ^[ 145ƒ~ƒŠ 35623: ‰Ĉ“dEƒJƒƒ‰
I shopped a lot for a substitute on this one. I could not find *any* other 145mm filters.
** The official Pentax 150mm SMC protective filter for the F*/FA* 600/4 and A*1200/8:
Amazon.co.jpF PENTAX SMC PFƒtƒBƒ‹ƒ^[ 150ƒ~ƒŠ 35624: ‰Ĉ“dEƒJƒƒ‰
--------
Now, you can't order any of these items from Amazon.co.jp unless you are in Japan, so you'll have to find someone to broker the transaction for you. One of our PF users, @Tom1803: View Profile: tom1803 - PentaxForums.com has been extremely helpful in brokering a couple of these transactions for me.
I hope this arcane knowledge has been helpful to you. If so, click the little thumbs up button over on the left. If not, well . :)
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Forum: Canon, Nikon, Sony, and Other Camera Brands
03-01-2012, 12:17 PM
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My compilation from D. Dinning at Nokia 808 PureView in focus: An interview with Damian Dinning - GSMArena.com the best source I could find to date:
 Quote: It all started about five years ago. We wanted to do optical zoom
We looked at folded optics for example, we looked at straight optics; various different configurations, and we couldn't make any of those work well enough.
Later on, when we were thinking about this problem again,
This is where, when you are using the default 5 MP setting, we take up to 7 pixels, take the information that you want from those pixels, and process that using some Nokia algorithms.
GSMArena: Why has no one else produced a 41MP sensor? Is it that expensive?
It's not cheap, but when you compare it to optical zoom, you would have to put more cost into the optics.
There are not many people that can manufacture optics at that level of precision, and you need optics, otherwise you just can't make it work.
it is more complicated than binning. We looked at a number of different methods how we could do this, and some methods preserve more detail
We haven't really made that comparison. What I can say is, depending on the interpolation and downsampling you use in Photoshop, it may be possible that you'll get similar performance.
In Photoshop, you typically might get a sharpness that looks higher, but you might get more noise
The companion chip takes the information directly from the sensor and scales it, before that data goes to the GPU.
We do have a digital stabilizer for video, which we are still tuning at the moment.
Carl Zeiss, yes. The [manufacturing] precision is ten times greater than with SLR [lenses]. There are five lenses, quite small at the top, and then get progressively larger as they approach the sensor. There's also a mechanical ND filter which can be controlled in Creative mode, similar to the N8.
In addition to the precision of the optics, one of the things we've been working on for some time is precision alignment. We have a live image sensor setup when we assemble the optics, so that each and every single module we make is built and then assembled with live feedback from the sensor to ensure proper alignment.
We co-developed the sensor.
GSMArena: Any word on who else is involved?
Unfortunately, not at this time.
[ eds: His boss at the press conference revealed it is Toshiba ;) ]
GSMArena: Are you going to share the technology?
No.
The problem you may have experienced using that algorithm, is that it couldn't adapt quickly enough to sudden bursts of sound.
Whereas with this capability, rather than being limited to a certain level, it's always able to resolve this much higher dynamic range, in terms of volume.
Typically you would need an external microphone to get similar performance capability. In addition to that, the frequency response range that we have is almost the same as CD
We're still optimizing the camera; we don't have the final hardware yet. We're still developing the algorithmsparticularly low-light. We still have plenty of work still to do in low-light. While the low-light images are significantly better than on other devices, we believe we can make them even better. |
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Forum: Pentax News and Rumors
03-02-2012, 07:05 AM
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as nice as this seems, they have just diminished the value of the "Limited" edition by releasing it twice!!!
They sold 1500 Silver units last year, at a premium price because there were only going to be 1500.
This just tells us there is nothing coming to replace the K-5 for a while.
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Forum: Pentax Full Frame
10-18-2011, 12:44 PM
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Last month, the owner of Pentaxeros.com (Spanish Pentax community/store) and I joined forces and wrote a letter to Pentax presenting a case for why Pentax needs to work on developing a full-frame DSLR.
The list of reasons what quite elaborate (here's a brief summary):
In any case, Pentax listened! Not only did we get a written response from the president of Pentax Europe, but he assured us that management in Japan (as well as the R&D department in Europe) will be forwarded our feedback, and that (following acquisition by Ricoh) the company plans on expanding its Advanced Amateur and Professional product lines. Once I get permission to post the letter, I will attach in in this thread!
Update: here is the response from Pentax |
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Forum: Pentax News and Rumors
02-22-2011, 05:13 PM
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 Fig.1: Accuracy of the Pentax K-5 phase detect AF vs. luminosity in EV. The above chart includes all measurements, i.e. various lenses, light colors, distances and apertures. The accuracy is measured as deviation of the focal plane from the sensor plane, in µm. [from the study linked below]
LumoLabs (that's me ;) ) has decided to have a closer look at the K-5 low light front focus issue. After careful evaluation and many hundred test shots I must say that the issue is real.
A preliminary copy of the paper was provided to Pentax earlier this week and the head of Pentax Europe officially receives a printed copy today. I have been told that Pentax engineering will receive a copy too.
The study
The results are too complex to be presented in the scope of a forum article. Fig.1 above may provide a first idea of the work though.
Please, refer to the full blog article and to the complete paper for our findings:
You'll gain a deeper understanding of Fig.1 too ;)
In a nutshell, this is what we find:- The K-5 as it presently ships indeed has a flaw in its phase detect autofocus module or software which causes it to front focus in low light below a lens-dependent threshold in EV.
- If it does, it seems to consistently focus ≈ 255 µm behind the sensor plane (although with a significant ħ 75 µm scatter of results which is about twice as large as the normal scatter of result).
- Faster lenses seem to keep working in lower light but of course, are prone to more blur when the front focus does eventually happen. Slower lenses can already start to front focus at light levels metering as 4 EV or 6 EV even. A fast lens may work down to 0 EV in white light.
- Light sources other than daylight emphasize this problem as they simply appear darker to the AF module. Moreover, it seems to be moderately color blind for red which further emphasizes the effect in deep tungsten light.
- The effect is real and can negatively impact the daily work of a photographer. On the other hand, it is possible to run into a low light tungsten situation without the problem.
- The paper clarifies conditions to hit or avoid the issue. White light (halogen is not white enough though) and a wide lens stopped down help to work around the problem. AF assist light typically doesn't help though. But an LED flash light does. ;)
- I don't rule out that a µm-valued variable becomes 0xFF (255) and causes a false shift of the focus plane by 255 µm. I call it the +0xFFµm hypothesis.
Please, keep discussion within this thread related to the above study and work which is based on experiments. We have another thread for the exchange of observations and opinions.
It is here: https://www.pentaxforums.com/forums/pentax-k-5-forum/128562-relevant-news-re-...ial-light.html
Thanks everybody for their motivation. I probably wouldn't have done it without. Again it turned out to be more work than anticipated ;)
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