Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-16-2018, 04:09 AM   #181
Pentaxian
photoptimist's Avatar

Join Date: Jul 2016
Photos: Albums
Posts: 5,113
QuoteOriginally posted by Class A Quote
That is true. It is, however, often useful to distinguish between "sensels" and "pixels".

In our discussion, the distinction is important because one is either talking about the alignment of raw data (sensel data) or demosaiced data (pixel data).
Agreed.

QuoteOriginally posted by Class A Quote
Of course.

Note that I stated that I do consider that a sensel alignment may have advantages. I furthermore never stated that Ricoh doesn't do sensel alignment. I just expressed that I'd be surprised if they did.

I specifically wrote "All that is required..." because before you were adamant that superresolution would only work at the sensel level. You wrote "it's not how super-resolution works" and "With super-resolution, extremely accurate knowledge of frame-to-frame alignment (as in knowing which sensels match across frames) is absolutely essential."

Hence my response that less than what you claimed is already sufficient.

It seems you now share my view that "superresolution" can work on RGB pixel data.
Yes, demosaiced data can work but it consumes 3X the RAM and is gets poorer results. If the RAW data is available, both the speed and the results are superior.

QuoteOriginally posted by Class A Quote


What Pixel Shift does best is avoid colour moiré and increase colour resolution (in particular for red and blue).
AFAIC, it is moot to argue about whether increasing colour resolution in this manner constitutes increasing "spatial resolution" (in the regular meaning of the word).
Well, you can shoot a USAF test target in B/W or in various colors and measure the significant enhancement of spatial resolution produced by Pixel Shift.

QuoteOriginally posted by Class A Quote

I believe you know what I mean when I try to distinguish between processes that either
  1. aim to emulate a sensor that records full RGB data at each pixel location, or
  2. aim to emulate a sensor with more pixels.
Personally, I'd reserve the use of "increasing spatial resolution" for the latter process, but I won't argue if you want to use it for the first process as well.
In the red channel, the K-1 is a 9 megapixel camera with sensels that have a 25% fill factor. The steps to use the K-1's low spatial resolution sensor to get full 36 MP of spatial resolution in RGB is identical to superresolution.

QuoteOriginally posted by Class A Quote


I personally wouldn't use that term for classic Pixel Shift (as I associate "superresolution" with sub-pixel shifting), but I won't argue that it is an incorrect usage.
Whether the shifts in the pixels are carefully controlled, carefully measured by SR sensors, carefully estimated from the image data, or some combination of the three really doesn't change the superresolution process much although careful shifting (original Pixel Shift) can produce superior results to uncontrolled "hand-shake" shifting (the new "dynamic pixel shift").

QuoteOriginally posted by Class A Quote
That's their statement but I'm assuming they may be considering adverse influences like motion in the scene, or perhaps they are not doing an exhaustive alignment analysis and hence include the possibility of errors?

Otherwise, it seems to me that a correlation analysis between the images should provide the best alignment possible. Acceleration measurements won't be 100% accurate or noiseless. Would you adjust a perfect alignment, just because camera movement measurements indicate that less sharpness should be obtained then actually possible by using a very slightly different alignment?
I'd use both the sensor data and the image data. To the extent that both sources are somewhat noisy but the noise is not 100% correlated, the combination is superior to either data source alone.

QuoteOriginally posted by Class A Quote
I'm not "choosing to disbelieve" at all.

What makes you think that?

I said that I believe that my description of "Dynamic Pixel Shift" is compatible with Pentax's description. So I never implied that they could be lying. All I said was that one should not read too much into marketing statements; meaning that marketing statements are not white papers. It is not uncommon for marketing statements to be not quite accurate in a technical sense, without any intention of deceit on behalf of the company.

To clarify, I'm not saying anyone, including you, is wrong about what "Dynamic Pixel Shift" is. I'm just saying I'd be surprised if some of the theories that have been offered accurately described the actual implementation.
That we can agree on. It's easy (and fun) to speculate but hard to know what's really going on without extensive testing.

04-16-2018, 05:54 AM   #182
Pentaxian
Andrea K's Avatar

Join Date: Mar 2009
Location: Rome, Italy
Posts: 822
QuoteOriginally posted by MJKoski Quote
Gosh! Such lack of vision. Backlit buttons, once you use them with a Nikon, are godsend feature for night shooting. Every model lacking those should be automatically reviewed with lower score.

OVF shutter, not a huge change but a must for long exposures. Now we have some leftover plastic residue as a cap. Incredibly futile and falls off easily.
About backlit buttons, slightly move the articulated screen away from the camera, push the button to turn on the leds.
About OVF shutter, use your glasses/lenses cleaning coth.
04-16-2018, 07:08 AM   #183
Pentaxian




Join Date: Sep 2011
Location: Nelson B.C.
Posts: 3,782
QuoteOriginally posted by MJKoski Quote
Just some thoughts since I got the mk2 on wednesday. Why should I write the same happy-happy joy-joy messages 95% of PF-members expect of a new Pentax model that have already been written? These are just digital soulless devices which deserve no more than they are worth. Every brand puts them out at steady pace.
I'm curious what you are seeing and why. I've noticed that iso performance is dependent on far more than simply the gain; I had an iso 6400 photo yesterday that had less noise than some iso 800 shots I have taken. I couldn't believe what I was seeing in the exif.

I guess the question is whether without the processing the image data would have been better. Any noise handling algorithms wherever they are applies are about attempting to reconstruct detail.

Thanks for posting the image. More information the better.
04-16-2018, 07:55 AM - 1 Like   #184
Senior Member




Join Date: Dec 2014
Photos: Gallery
Posts: 168
I find that when people test iso, they forget how big an influence light is.

04-16-2018, 09:44 AM   #185
Loyal Site Supporter
Loyal Site Supporter
Mikesul's Avatar

Join Date: Sep 2009
Location: Phoenix, AZ
Posts: 7,584
QuoteOriginally posted by CNunez Quote
I find that when people test iso, they forget how big an influence light is.
Yes! This sounds funny but he is correct. The better the light the higher you can go with the ISO, it seems.
04-16-2018, 11:31 AM - 1 Like   #186
Master of the obvious
Loyal Site Supporter
savoche's Avatar

Join Date: Jun 2011
Location: Lowlands of Norway
Posts: 18,309
QuoteOriginally posted by Mikesul Quote
Yes! This sounds funny but he is correct. The better the light the higher you can go with the ISO, it seems.
Exactly so. The noise amounts to the square root of the signal. While that means that you actually have more noise with more light, the noise makes up a much smaller fraction of the total (signal+noise) than when there are fewer photons captured. If you capture 100 times more light you will increase the amount of noise only 10 times.

Or to look at it in another way; it's not high ISO that gives you noisy images, it's the lack of light. (But yes, when you increase the ISO you will let in less light to avoid overexposure. So in practical terms high ISO gives more noise.)
04-16-2018, 06:22 PM - 2 Likes   #187
Pentaxian




Join Date: Dec 2015
Posts: 740
?????? K-1 MarkII?????????????? ? ?? ?????????? ??309??????? - ????

04-16-2018, 07:00 PM   #188
maw
Pentaxian
maw's Avatar

Join Date: Feb 2014
Location: Sassari (Italy)
Posts: 1,118
Hi OoKU,

Beautiful, great latitude of laying seems to me. Punctiform stars also,

great job.
04-17-2018, 05:08 AM   #189
Pentaxian
Andrea K's Avatar

Join Date: Mar 2009
Location: Rome, Italy
Posts: 822
Why in the picture data there are two values of time ? "15mm・20.0sec+80.0sec・iso6400・F/2.8"
04-17-2018, 06:41 AM   #190
Veteran Member
DimC's Avatar

Join Date: Jul 2012
Location: Paris
Photos: Gallery | Albums
Posts: 813
QuoteOriginally posted by Andrea K Quote
Why in the picture data there are two values of time ? "15mm・20.0sec+80.0sec・iso6400・F/2.8"
I was thinkin about 2 different exposure, foreground (20sec) and Stars (80sec).
04-19-2018, 09:27 PM - 1 Like   #191
Site Supporter
Site Supporter




Join Date: Mar 2017
Photos: Gallery | Albums
Posts: 568
QuoteOriginally posted by DimC Quote
I was thinkin about 2 different exposure, foreground (20sec) and Stars (80sec).
Most likely the other way around. 80 sec foreground, 20 sec stars. At 80 secs, stars will be streaks unless you have astrotracer on or a tracking mount. And in either of those cases the foreground would blur.
But 80 secs foreground might be enough to lighten it up to show detail in a composite image with a 20 sec MW shot.
04-19-2018, 11:24 PM   #192
Veteran Member
DimC's Avatar

Join Date: Jul 2012
Location: Paris
Photos: Gallery | Albums
Posts: 813
QuoteOriginally posted by SteveinSLC Quote
Most likely the other way around. 80 sec foreground, 20 sec stars. At 80 secs, stars will be streaks unless you have astrotracer on or a tracking mount. And in either of those cases the foreground would blur.
But 80 secs foreground might be enough to lighten it up to show detail in a composite image with a 20 sec MW shot.
Yep, I mixed things up !
04-20-2018, 06:09 AM - 1 Like   #193
JPT
Pentaxian




Join Date: Jan 2012
Location: Tokyo
Photos: Gallery
Posts: 2,817
The K-1 mark 2 went on sale today in Japan, and a number of camera store bogs have reports on the camera. Of course, the main objective is to make you want to buy the camera from them, so they are not really objective or critical.

Yaotomi Camera's blog is probably the most informative. There are plenty of images, some of them full size.
Part 1: ?????? K-1 MarkII?????????????? ? ?? ?????????? ??309??????? - ????
Part 2: ?????? K-1 MarkII?????????????? ? ?? ???? ???? 2018 - ????
Part 3: ?????? K-1 MarkII??????????? ? ?? ??????????????????? 2018 - ????

A report from Yodobashi Camera
PENTAX???????? K-1 Mark II ?????? | ???????

From Map Camera
?????? | KASYAPA | 475:?????????????K??PENTAX K-1 Mark II? | PENTAX & RICOH

From Fujiya Camera
PENTAX K-1 II ???? | ??????????
05-01-2018, 08:08 AM - 1 Like   #194
JPT
Pentaxian




Join Date: Jan 2012
Location: Tokyo
Photos: Gallery
Posts: 2,817
Yaotomi is really going to town with the K-1 mark 2. They are now up to Part 8 of their sample photos.

Part 4: ?????? K-1 MarkII??????????? ? ?? ?????????????? - ????
Part 5: ?????? K-1 MarkII??????????? ? ?? ??????????? 2018 - ????
Part 6: ?????? K-1 MarkII??????????? ? ?? ???? ????????? 2018 - ????
Part 7: ?????? K-1 MarkII??????????? ? ?? ?????? 2018 - ????
Part 8: ?????? K-1 MarkII??????????? ? ?? ??????????? ??309????? 2018 - ????
05-02-2018, 10:29 PM   #195
Pentaxian
Class A's Avatar

Join Date: Aug 2008
Location: Wellington, New Zealand
Posts: 11,250
DPReview have published a K-1 II sample gallery. A "full review" is supposed to follow.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, dslr, full frame, full-frame, ii, k-1, k-1 mark ii, k1, mark, pentax k-1, pentax k-1 mark, photographers, pictures, pixels, pp, psr, results, reviews, sensor, shift, spectra, term, utility, weeks
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentax K-1 Mark II DSLR camera detailed specifications leaked Craig66 Pentax News and Rumors 389 02-19-2018 10:34 AM
Pentax K3 ii vs Canon 5D mark ii mogge Welcomes and Introductions 49 03-27-2016 02:39 AM
Lens Reviews - Camera used not listed on 3rd party lens reviews? ak_kiwi Pentax SLR Lens Discussion 3 02-15-2014 01:34 PM
Reviews really missed the mark on Kr AWB in tungsten light LRB21 Pentax K-r 3 09-06-2011 03:12 PM



All times are GMT -7. The time now is 11:29 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top