Site Sponsors
Page 4 of 5 FirstFirst ... 2 3 4 5 LastLast
Results 151 to 200 of 211

Thread: Seeing any Posterization issues with A7r ll?

  1. #151
    Senior Member Amin's Avatar
    Join Date
    Dec 2007
    Location
    Boston, MA (USA)
    Posts
    1,809
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    David, I don't agree that the boundaries of the issue have been defined.

    We don't know to what extent (if any) Lloyd's use of lens compensation settings affected the gaps in the raw data.

    We don't know to what extent (if any) another camera with uncompressed or losslessly compressed 14-bit raw would have shown similar effects with the same subject, degree of relative underexposure, and color management.
    Likes 1 Member(s) liked this post

  2. #152
    Senior Member Slingers's Avatar
    Join Date
    Feb 2013
    Location
    Sydney, Australia
    Posts
    457
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by timparkin View Post
    Well here's one that shows up in a print

    http://static.timparkin.co.uk/onland...akes/tiled.jpg

    Tim
    Thanks for this. I find it interesting that's it's the same artefact problem as the star trail image that is used everywhere but with the inverse of sky highlights against the dark background of the tree but the same rounding errors of the compression. It's a scenario I guess we need to be mindful of until the compression is fixed.

  3. #153
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    Hey folks first I want to apologize here on this thread. I may have been a little aggressive in some of my comments so please do not take any offense to that. I simply hate bad data and its been going around on this Sony for reasons I am not sure and people that should be doing there job are in my mind not being very Professional. As you all know I have been in this a very long time and my passion level for this industry is extremely high. I made a good career out of it and it served me well so i care a great deal. Which sometime my red hot Italian blood does get to a boil once in awhile. So for that I am sorry. I also had stuff going on with a personal level that does concern my wife and her health. We have not won the battle but today we are on at least on some neutral ground. Some good news and some stuff we need to address. I get PM's from you folks and I love you all for it. I try not to talk to much about it but holding stuff in is not good for me either and this battle has been going for almost 6 years. In closing I care dearly for our members and I love the respect you show me even though there maybe days I don't deserve it. You are my friends and I do care about you all and your love for Photography..

    Okay working on my test stuff. Hope to have this up soon. Im pretty blown away by what Im seeing. Have a great weekend
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com
    Thanks 1 Member(s) thanked for this post
    Likes 6 Member(s) liked this post

  4. #154
    Senior Member mjm6's Avatar
    Join Date
    Jul 2009
    Location
    Sacramento, CA
    Posts
    526
    Post Thanks / Like
    Images
    15

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Iliah Borg View Post
    First and foremost, try to not underexpose, that means per channel underexposure, not just overall exposure to the right. Consider this: red channel is week, and white balance multiplier for the red channel is 2.4 on this shot, that is even with green channel exposed to the right the red channel is still underexposed more than 1 stop. For daylight shooting a magenta filter (like a Lee CC40M / CC50M) on the lens will bring the channels more to the balance.

    I've been working with a variation of this to improve the file for B&W conversion! Shhhh... it's a secret.

    Basically, if you are shooting for B&W conversion, you are at a distinct disadvantage if you intend to 'red' or 'orange' filter the image as part of the conversion because of exactly what Iliah has indicated in this quote.

    Add to that all the baked in RAW adjustments that you don't even know are occurring, and you have possibly lost a huge amount of data from the Red channel.

    Now, I don't know about you folks, but using a Red or Orange filter on the image in the traditional manner with film often produced a better aesthetic for my work than shooting without, and I certainly don't want to use a Blue filter unless you were aiming for the old Orthochromatic look. A Green sometimes worked OK for me, but normally, I favored the Y, OR, or R.

    So, the point is to knock down the Green and Blue channels somewhat to raise the Red channel and ensure that you have sufficient information in the Red channel for your manipulation that you will be doing later in LR.

    You don't really have to fret the G channel since it is much stronger than the R.

    If you've ever done a B&W conversion using the filtration approach (rather than just combining the channels in to a single channel), and then had problems with posterization in the sky when you went to do any burning, you know why this approach is will produce a better result. Actually, I've seen posterization without even doing any burning...

    I suppose I should do a writeup on this and become internet famous (and not for my account at VM!). Just kidding about the VM account.


    ---Michael
    a7r, a7rII, FE 16-35, FE 24-70GM, FE 70-200, Loxia 21mm, 35mm, 50mm
    Likes 1 Member(s) liked this post

  5. #155
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    Wanted to go back to this for a second because I have shot many times in Yosemite national park at the 10k and above elevations and we used to use with our ND filters up at that elevation IR ND filters because of the IR bleed at those heights Color is actually diffrent at these elevations because of the IR .

    For our engineers folks and scientist would this not have a color effect. Certainly seems it since a IR ND works best. Just a thought
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com
    Likes 1 Member(s) liked this post

  6. #156
    Workshop Member
    Join Date
    Nov 2007
    Location
    Brooklyn
    Posts
    4,043
    Post Thanks / Like
    Images
    1253

    Re: Seeing any Posterization issues with A7r ll?

    in my high altitude experience a UV filter was required to get rid of the excess short wavelength (blue-UV) light less absorbed by the thinner atmosphere and reduced absorption path compared to lower elevations

  7. #157
    Subscriber Member tashley's Avatar
    Join Date
    Jan 2008
    Location
    South of England
    Posts
    3,295
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by jlm View Post
    in my high altitude experience a UV filter was required to get rid of the excess short wavelength (blue-UV) light less absorbed by the thinner atmosphere and reduced absorption path compared to lower elevations
    so that might mean that the relative proportions of red to blue light were low? Not sure if Lloyd's polariser was also a uv?

  8. #158
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    That was why I brought it up. It was something that was never mentioned was the elevation where these shots are taken . The light change is pretty big

    Tim I'm not so sure a polarizer has that built in to it. Never seen one where that was advertised.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  9. #159
    Subscriber Member tashley's Avatar
    Join Date
    Jan 2008
    Location
    South of England
    Posts
    3,295
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Guy Mancuso View Post
    That was why I brought it up. It was something that was never mentioned was the elevation where these shots are taken . The light change is pretty big

    Tim I'm not so sure a polarizer has that built in to it. Never seen one where that was advertised.
    I'm sure I've got a couple knocking about somewhere. If my filter draw didn't make Pandora's Box look like a Scandinavian design statement, I'd look.
    Likes 1 Member(s) liked this post

  10. #160
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    Lol

    Well I do think this elevation has a effect on that file. Hopefully our brain trust here can figure it out.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  11. #161
    Super Duper
    Senior Member
    Vivek's Avatar
    Join Date
    Apr 2008
    Location
    Netherlands
    Posts
    13,604
    Post Thanks / Like
    Images
    21

    Re: Seeing any Posterization issues with A7r ll?

    Guy, Why invoke science and engineering, there are many good ones that are also capabale just as there are good photographers who can read light and make their tools capture it.

  12. #162
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    Well because I know for a fact at those elevations the wave length changes. That's my brain knowing that but I need engineers to do the match and science on how much it would effect the file. That part is where I get off the bus and ask for directions. We need the science but we also need the reality
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  13. #163
    Workshop Member
    Join Date
    Nov 2007
    Location
    Brooklyn
    Posts
    4,043
    Post Thanks / Like
    Images
    1253

    Re: Seeing any Posterization issues with A7r ll?

    quite a few factors contribute to the relative IR-UV content at different elevations and it's effect, atmosphere and atmospheric composition being one. also angle of light, reflectivity of surroundings. e.g.: air in tokoyo vs Chamonix; snow and sand, dark earth, high noon, vs sunset, spectral sensitivity of the sensor, film (or your skin, for example)

    when skiing or at the beach, you need dark UV safe eyewear and sunscreen; if photographing near snow, definitely a UV filter, etc

  14. #164
    Member
    Join Date
    Aug 2015
    Posts
    20
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by tashley View Post
    so that might mean that the relative proportions of red to blue light were low? Not sure if Lloyd's polariser was also a uv?
    Blue channel on non-UV-enabled silicon sensors has extremely low sensitivity to wavelengths shorter than about 380nm, UV per se should not be an issue, sensors are not like film in that regards. Page 6 of http://www.lpriami.altervista.org/Im...r_ICX445-4.pdf gives an idea. Also, most of the lenses attenuate UV dramatically.

    But red to blue ratio on the water and in skies is always low, which makes the red very important, but very brittle at the same time (it is red that adds all the drama in the sky, bw photographers know it allright). That ratio can be easily worse with a polarizer. With digital cameras, red and magenta filters are still useful to remedy this problem.

  15. #165
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    So no one has a answer to my question.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  16. #166
    Member
    Join Date
    Jul 2008
    Location
    Leeds, UK
    Posts
    127
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Guy Mancuso View Post
    So no one has a answer to my question.
    Yes you are right. This is due to molecules scattering higher frequencies of light from the sun (Rayleigh or Tyndall Scattering). However this blue light has to travel through the atmosphere to get to your eye and hence it gets attenuated itself (the blue light trying to get to your sky get attenuated by scattering). Add in dust scatter and humidity reduced viewing distance (haze) and the lower you are the more non-blue light reaches you as well.

    High up you get a deep blue because less blue is scattered but there is less (also thinner) atmosphere to pollute the blue.

    Add a polariser to this and you can end up with the sky almost black (you effectively have a luminance control of the blue channel with your polariser).

    Reflections from waves will alternately reflect the black, polarised sky and possible areas of non-polarised sky (and maybe transparent areas showing the green of the water).

    Tim

    p.s. Dana Lake is at 11,100 ft
    Thanks 1 Member(s) thanked for this post

  17. #167
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    Thanks Tim appreciate this so should we be adding this to the effect that he is getting. The problem to this file is it really started off bad or everything against it to begin with than obviously post and other issues it went to hell in a hand basket.

    Really if you ask me a lot on contributing factors and not necessary pointing in one area but basically a combined fail.

    I know when I shoot up there we use IR ND filters
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  18. #168
    Super Duper
    Senior Member
    Vivek's Avatar
    Join Date
    Apr 2008
    Location
    Netherlands
    Posts
    13,604
    Post Thanks / Like
    Images
    21

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Guy Mancuso View Post

    Really if you ask me a lot on contributing factors and not necessary pointing in one area but basically a combined fail.
    I would think not.

    Metamerism failure is directly equated to lossy RAW files (the original query in this post). I think that is wrong.

    The sidebar/discussions are all fine and very enlightening but the reviewer came to the wrong conclusions not recognizing what he did wrong.

  19. #169
    Subscriber Member tashley's Avatar
    Join Date
    Jan 2008
    Location
    South of England
    Posts
    3,295
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Vivek View Post
    I would think not.

    Metamerism failure is directly equated to lossy RAW files (the original query in this post). I think that is wrong.

    The sidebar/discussions are all fine and very enlightening but the reviewer came to the wrong conclusions not recognizing what he did wrong.
    So just to be clear Vivek, what did he do wrong in your view?

  20. #170
    Super Duper
    Senior Member
    Vivek's Avatar
    Join Date
    Apr 2008
    Location
    Netherlands
    Posts
    13,604
    Post Thanks / Like
    Images
    21

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by tashley View Post
    So just to be clear Vivek, what did he do wrong in your view?
    Making a story that the lossy RAW was to blame for his posterization snaps.

  21. #171
    Subscriber Member tashley's Avatar
    Join Date
    Jan 2008
    Location
    South of England
    Posts
    3,295
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Vivek View Post
    Making a story that the lossy RAW was to blame for his posterization snaps.
    So are you 100% certain that the posterisation has nothing to do with lossy RAW?

    If so, what have you concluded was responsible?

  22. #172
    Super Duper
    Senior Member
    Vivek's Avatar
    Join Date
    Apr 2008
    Location
    Netherlands
    Posts
    13,604
    Post Thanks / Like
    Images
    21

    Re: Seeing any Posterization issues with A7r ll?

    Perhaps you read selectively, Tim?

    I said metamerism failure (here or another thread). Guy has brought in his pesronal experience to that as well.

  23. #173
    Subscriber Member tashley's Avatar
    Join Date
    Jan 2008
    Location
    South of England
    Posts
    3,295
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Vivek View Post
    Perhaps you read selectively, Tim?

    I said metamerism failure (here or another thread). Guy has brought in his pesronal experience to that as well.
    I have a reading age of 54. I asked what Lloyd did wrong, and you replied:

    "making a story that the lossy raw was to blame for his posterisation snaps"

    I think it's reasonable, given exactly what you wrote, to ask what therefore WAS in your view responsible. No?

  24. #174
    Super Duper
    Senior Member
    Vivek's Avatar
    Join Date
    Apr 2008
    Location
    Netherlands
    Posts
    13,604
    Post Thanks / Like
    Images
    21

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by tashley View Post
    I have a reading age of 54. I asked what Lloyd did wrong, and you replied:

    "making a story that the lossy raw was to blame for his posterisation snaps"

    I think it's reasonable, given exactly what you wrote, to ask what therefore WAS in your view responsible. No?
    Hi Tim, when the answer has been provided and if keep repeating your query, there are several possibilities (reading age being not one, i would think since I am in the same age bracket, well over the hill anyway)- a) I am not clear (can't do much about that), b) you do not understand what is said c) you do understand but refuse to accept what i said.

    Cheers!

  25. #175
    Subscriber Member tashley's Avatar
    Join Date
    Jan 2008
    Location
    South of England
    Posts
    3,295
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Vivek View Post
    Hi Tim, when the answer has been provided and if keep repeating your query, there are several possibilities (reading age being not one, i would think since I am in the same age bracket, well over the hill anyway)- a) I am not clear (can't do much about that), b) you do not understand what is said c) you do understand but refuse to accept what i said.

    Cheers!
    a)

  26. #176
    Member
    Join Date
    Jul 2009
    Location
    The Netherlands
    Posts
    38
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    It is somewhat surprising that Lloyd does apparently not have to explain himself. a lot of things he does not like are blamed on 'cooked' RAW files, which apparently means the compression algorithm. And as far as I know without really understanding the basic thinking behind the compression. the part of the compression where Sony divides an image up in squares and limits the dyncamic range within that square to less then the full dynamic range of the sensor, is certainly a potential problem. there are plenty of examples of how this mechanism can cause visible artifacts (although I have never encountered it in a file of mine, and apparently this goes for a lot of other Sony users as well). the other part of the compression, the part that apparently is blamed for posterisation and maybe even for 'orange peel', is not really lossy in the sense that little or no information is being lost. this is the part is where the tone curve is being compressed. so this part of the compression would influence parts of the image with little detail and low contrast (like in the example where posterisation occurs). there is less resolution after this operation, but the reasoning behind it is sound in that the part of the resolution that is thrown away does not contain information, but only (mostly) shot noise. It is possible to have a philosophical discussion about what is lost or not, and whether this could degrade an image, but this is unlikely to have much practical value. and Lloyd would not be an interesting partner in such a discussion, since he does not seems to be willing to try and understand the underlying theory (he and I have had discussions about this in the past).

  27. #177
    Senior Member mjm6's Avatar
    Join Date
    Jul 2009
    Location
    Sacramento, CA
    Posts
    526
    Post Thanks / Like
    Images
    15

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Vivek View Post
    Perhaps you read selectively, Tim?

    I said metamerism failure (here or another thread). Guy has brought in his pesronal experience to that as well.
    Vivek,

    I'm not sure you are using the term metamerism correctly in this context? I don't believe this is an issue of the colors appearing differently under two different light sources.

    I do agree that Lloyd appears to have made more of a fool of himself than add anything to the web knowledge base on the new camera or enlighten the masses on any issues of RAW compression.

    I don't know if the Sony a900 uses the exact same compression algorithm, but if it does, it would be possible to construct an A/B comparison to see if the RAW compression added to the problem that he experienced. I suspect that any impact is minimal at best, and it is almost entirely a case of gamut and spectral sensitivity in combination with the polarizer and elevation.

    That said, since RAW compression is obviously the boogieman, Sony could eliminate it as the problem de jure with some effort, and eliminate most of these inane discussions.


    ---Michael
    a7r, a7rII, FE 16-35, FE 24-70GM, FE 70-200, Loxia 21mm, 35mm, 50mm

  28. #178
    Member
    Join Date
    Aug 2015
    Posts
    20
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by timparkin View Post
    Yes you are right. This is due to molecules scattering higher frequencies of light from the sun (Rayleigh or Tyndall Scattering). However this blue light has to travel through the atmosphere to get to your eye and hence it gets attenuated itself (the blue light trying to get to your sky get attenuated by scattering). Add in dust scatter and humidity reduced viewing distance (haze) and the lower you are the more non-blue light reaches you as well.

    High up you get a deep blue because less blue is scattered but there is less (also thinner) atmosphere to pollute the blue.

    Add a polariser to this and you can end up with the sky almost black (you effectively have a luminance control of the blue channel with your polariser).

    Reflections from waves will alternately reflect the black, polarised sky and possible areas of non-polarised sky (and maybe transparent areas showing the green of the water).

    Tim

    p.s. Dana Lake is at 11,100 ft
    Dear Tim,

    To put some numbers to this,
    {"Sony", "ILCE-7RM2", "Daylight", {2.42578f, 1.0f, 1.58203f, 1.0f}},
    {"Sony", "ILCE-7RM2", "8500K", {3.06250f, 1.0f, 1.23438f, 1.0f}},

    The above is white balance multipliers for R, G1, B, G2 channels.
    R to R ratio is 3.06250 / 2.42578, that is at 8500K CCT the response in red is 80% of what it is for the normal photographic daylight, 5500K. This alone is too small of a difference to have a drastic effect - it is 1/3 EV only.

    But a polarizer complicates the situation by an unknown factor, as we do not know neither the primary effect - the angle (polarizer rotation), nor the secondary, that is how the polarizer (again, at the given angle) interferes with polarization effects in the sensor sandwich.

  29. #179
    Member
    Join Date
    Aug 2015
    Posts
    20
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    > add anything to the web knowledge base
    Lloyd presented experimental data and demonstrated several important issues:
    - imperfection of default colour management;
    - importance of watching for per channel exposure;
    - importance of watching for extreme attenuation of the red channel due to the use of polarizing filters (falls somewhat into the per channel exposure);
    - complete voids in raw data coming from the camera, stretched to 7-8 missing values after applying white balance (posterization of raw data).

    I would say it is quite a lot.
    Thanks 1 Member(s) thanked for this post
    Likes 1 Member(s) liked this post

  30. #180
    Member
    Join Date
    Mar 2013
    Posts
    70
    Post Thanks / Like

    Question Re: Seeing any Posterization issues with A7r ll?

    I suppose that the question is "which of these effects are features of this camera and which would happen with competing models"? In particular, which are attributable to the compression algorithm that Sony have chosen to adopt.

    The idea that removing the compression is just a matter of tweaking the firmware may or may not be the case. Sony's reluctance to offer the option of losslessly compressed raw suggests that there would be unwanted side effects. It would be interesting to know what those would be. Since it is reasonable to assume that the Sony engineers are not idiots, they have chosen the processing pipeline for a reason. I am not clear what it is? Card space saving? Frame rate? ... ? Does anyone else?

    I have read that Sony / Minolta used to have a non-lossy compression, provided the option of this lossy one, and moved over to it completely, when no one complained.

    The idea that ree to offer the option of losslessly compressed raw suggests that there would be unwanted side effects. It would be interesting to know what those would be.

  31. #181
    Subscriber & Workshop Member GrahamWelland's Avatar
    Join Date
    Nov 2007
    Location
    Vancouver, WA
    Posts
    5,802
    Post Thanks / Like
    Images
    564

    Re: Seeing any Posterization issues with A7r ll?

    Btw is this specific to the A7RII or all of the cameras using Sony's imaging pipeline, compression and raw format?
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"

  32. #182
    Senior Member mjm6's Avatar
    Join Date
    Jul 2009
    Location
    Sacramento, CA
    Posts
    526
    Post Thanks / Like
    Images
    15

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Iliah Borg View Post
    > add anything to the web knowledge base
    Lloyd presented experimental data and demonstrated several important issues:
    - imperfection of default colour management;
    - importance of watching for per channel exposure;
    - importance of watching for extreme attenuation of the red channel due to the use of polarizing filters (falls somewhat into the per channel exposure);
    - complete voids in raw data coming from the camera, stretched to 7-8 missing values after applying white balance (posterization of raw data).

    I would say it is quite a lot.

    The top three are known troubles associated with digital imaging and have been for years.

    The bottom is clearly an issue, but is it the fault of the camera or the top three? I've seen gamut manipulations do some pretty drastic appearing things on the fringes, and at this point I don't believe that this is really anything beyond that unless there has been an effort to prove that the compression is the culprit. It may be, but it is also not inconsistent with how digital files have behaved from other cameras under other circumstances in the past when the gamut it strongly challenged.


    ---Michael
    a7r, a7rII, FE 16-35, FE 24-70GM, FE 70-200, Loxia 21mm, 35mm, 50mm

  33. #183
    Senior Member Amin's Avatar
    Join Date
    Dec 2007
    Location
    Boston, MA (USA)
    Posts
    1,809
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Iliah Borg View Post
    > add anything to the web knowledge base
    Lloyd presented experimental data and demonstrated several important issues:
    - imperfection of default colour management;
    - importance of watching for per channel exposure;
    - importance of watching for extreme attenuation of the red channel due to the use of polarizing filters (falls somewhat into the per channel exposure);
    - complete voids in raw data coming from the camera, stretched to 7-8 missing values after applying white balance (posterization of raw data).

    I would say it is quite a lot.

    If Lloyd had written a post presenting the above issues in a level-headed manner, he would have gotten a lot of positive feedback. Instead, he talked about how he was "flabbergasted" by the results of an ISO 100 image taken with a "nearly optimal exposure" and suggested that these results were because of the compression scheme used by "a company that really doesn't understand photography".

  34. #184
    Subscriber Member tashley's Avatar
    Join Date
    Jan 2008
    Location
    South of England
    Posts
    3,295
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by mjm6 View Post
    The top three are known troubles associated with digital imaging and have been for years.

    The bottom is clearly an issue, but is it the fault of the camera or the top three? I've seen gamut manipulations do some pretty drastic appearing things on the fringes, and at this point I don't believe that this is really anything beyond that unless there has been an effort to prove that the compression is the culprit. It may be, but it is also not inconsistent with how digital files have behaved from other cameras under other circumstances in the past when the gamut it strongly challenged.


    ---Michael
    Michael, I think the truth is, we'll never know. I think you can discount factor 1) because the RAW file is quite badly posterised before colour management. The exposure was actually quite good, protecting the highlights on the face, but were it to have been bracketed so that the most optimally ETTR file could have been chosen, maybe things would have been different. However at this level of exposure one would not expect posterisation, or at least, I wouldn't. And I think in practical terms most of us don't expect to have to shoot with a magenta filter though I am sure that would have helped. The polariser is the joker in the pack.

    One may or may not like Lloyd's style of presentation (Amin clearly does not) but as Iliah says, quite a lot has been demonstrated and I think we have all exercised our brains and learned some new stuff here.

    My read of Iliah (he and his colleague Alex are they only people apart from Lloyd and me to have seen the RAW file, but I consider him a very great deal more qualified than me to judge it) is that he thinks the some aspect of the RAW file pipeline is partly to blame, quite possibly regardless of the other factors. I am sure he can answer that directly himself and I would love to hear his answer, even if it's "It isn't possible to say without more information."
    Thanks 1 Member(s) thanked for this post
    Likes 1 Member(s) liked this post

  35. #185
    Super Duper
    Senior Member
    rayyan's Avatar
    Join Date
    Jan 2008
    Posts
    5,887
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    The raw pipeline!

    Here is a quote from a source that shall remain nameless

    "Even though Sony has promised 14 bit raw, it isn’t going to fix the hardware compression that’s occurring before recording – we’re just going to have a larger container (i.e. bigger files) for the same amount of information."

    Could there be some merit in the above statement? Hey, I just use raw...I don't know ( I leave the heavy stuff to the experts ) the intricacies of it all. Get .nef files
    Or whatever, open in a converter, do some manipulation and like magic it seems to be there.

    Kind regards.

  36. #186
    Member
    Join Date
    Aug 2015
    Posts
    44
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by rayyan View Post
    The raw pipeline!
    "Even though Sony has promised 14 bit raw, it isn’t going to fix the hardware compression that’s occurring before recording – we’re just going to have a larger container (i.e. bigger files) for the same amount of information."
    Kind regards.
    I think that's unlikely...they would at least have to ditch the delta compression, or it would be an utterly pointless exercise. Presenting the same lossy data, in an uncompressed format, would solve nothing, and Sony knows that.

    They might still cook the RAW (e.g. we might still have orange peel textures to deal with), but losing the RAW artifacts along high contrast borders caused by delta compression would be better than nothing.
    Thanks 1 Member(s) thanked for this post

  37. #187
    Senior Member mjm6's Avatar
    Join Date
    Jul 2009
    Location
    Sacramento, CA
    Posts
    526
    Post Thanks / Like
    Images
    15

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by rayyan View Post
    The raw pipeline!

    Here is a quote from a source that shall remain nameless

    "Even though Sony has promised 14 bit raw, it isn’t going to fix the hardware compression that’s occurring before recording – we’re just going to have a larger container (i.e. bigger files) for the same amount of information."

    Could there be some merit in the above statement? Hey, I just use raw...I don't know ( I leave the heavy stuff to the experts ) the intricacies of it all. Get .nef files
    Or whatever, open in a converter, do some manipulation and like magic it seems to be there.

    Kind regards.
    Whoa, wait a minute... I think you are conflating lossless compression with lossy compression.

    Nobody here is talking about lossless compression that I am aware of. This is entirely regarding the lossy compressed RAW files that Sony uses to drop the file size (and possibly some other artifact from the image processing pathways, who knows). As Spence mentions, the Delta compression.

    If they implement a lossless compression scheme that reduces file size but does not actually eliminate information that was available to record, that is the question, and it is also what many, many people feel is the right thing to do. Me included. Give me larger files to know that at least the image file has everything that the device was able to collect.


    ---Michael
    a7r, a7rII, FE 16-35, FE 24-70GM, FE 70-200, Loxia 21mm, 35mm, 50mm

  38. #188
    Senior Member mjm6's Avatar
    Join Date
    Jul 2009
    Location
    Sacramento, CA
    Posts
    526
    Post Thanks / Like
    Images
    15

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by tashley View Post
    Michael, I think the truth is, we'll never know...

    Thanks, I agree. I think the combination of a really blue/green lake, high altitude, and a polarizer has resulted in a torture test that possibly many (all?) cameras will fail without taking special precautions.

    I guess this was my point. If this were to occur on a scene that didn't have these very unique color gamut kinds of problems, I would be concerned. But this problem he generated isn't really shown to be that yet. I think he would have been better advised to explore the situation more before making the posts that he did. Seems a bit Chicken Little to me.


    ---Michael
    a7r, a7rII, FE 16-35, FE 24-70GM, FE 70-200, Loxia 21mm, 35mm, 50mm

  39. #189
    Senior Member Malina DZ's Avatar
    Join Date
    Mar 2013
    Location
    S. Florida
    Posts
    549
    Post Thanks / Like
    Images
    1

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by jrp View Post
    Since it is reasonable to assume that the Sony engineers are not idiots, they have chosen the processing pipeline for a reason. I am not clear what it is? Card space saving? Frame rate? ... ? Does anyone else?
    How about priorities over video capture speed and resolution? Lossy compression allows Sony to achieve not only 12FPS for 24MPx stills (a77), but also record video files to SD card at a higher frame rate and resolution compared to Canikon DSLRs.

  40. #190
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by mjm6 View Post
    Thanks, I agree. I think the combination of a really blue/green lake, high altitude, and a polarizer has resulted in a torture test that possibly many (all?) cameras will fail without taking special precautions.

    I guess this was my point. If this were to occur on a scene that didn't have these very unique color gamut kinds of problems, I would be concerned. But this problem he generated isn't really shown to be that yet. I think he would have been better advised to explore the situation more before making the posts that he did. Seems a bit Chicken Little to me.


    ---Michael
    This is exactly my point all along.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com
    Likes 1 Member(s) liked this post

  41. #191
    Senior Member
    Join Date
    Dec 2007
    Location
    Melbourne, Australia
    Posts
    261
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by mjm6 View Post
    Thanks, I agree. I think the combination of a really blue/green lake, high altitude, and a polarizer has resulted in a torture test that possibly many (all?) cameras will fail without taking special precautions.

    I guess this was my point. If this were to occur on a scene that didn't have these very unique color gamut kinds of problems, I would be concerned. But this problem he generated isn't really shown to be that yet. I think he would have been better advised to explore the situation more before making the posts that he did. Seems a bit Chicken Little to me.


    ---Michael
    Diglloyd generates traffic $$$ by making mountains out of mole-hills.

  42. #192
    Senior Member ErikKaffehr's Avatar
    Join Date
    Oct 2012
    Location
    Nyköping Sweden
    Posts
    1,194
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Hi Tim,

    From what I can see in the samples it is not entirely clear what phenomena are attributed to the "orange peel" effect and what is called posterisation.

    Much of the area is out of focus so it can be hard to say what is a wave and what is a possible artefact.

    Something I noticed is that both Tim Ashley, Lloyd Chambers and myself apply quite a bit intensive sharpening, which is often combined with some masking. I have noticed with my settings that this can cause artefacts. Large amount of low radius sharpening enhances noise. The masking removes sharpening in parts of the image, causing the visible grain pattern to switch on and off. This can often be observed as grain pattern in contours along edges.

    In my humble opinion we are sharpening quite a lot at the pixel level which is really seldom optimal. Pictures are not intended to be viewed at the pixel level and prints probably need most sharpening in the low to medium frequencies, say 10-30 lp/mm on 135 film, where the contrast sensivity of human vision is highest. But, he who is without sin may throw the first stone, and that will certainly not be me…

    Best regards
    Erik

    Quote Originally Posted by timparkin View Post
    Yes you are right. This is due to molecules scattering higher frequencies of light from the sun (Rayleigh or Tyndall Scattering). However this blue light has to travel through the atmosphere to get to your eye and hence it gets attenuated itself (the blue light trying to get to your sky get attenuated by scattering). Add in dust scatter and humidity reduced viewing distance (haze) and the lower you are the more non-blue light reaches you as well.

    High up you get a deep blue because less blue is scattered but there is less (also thinner) atmosphere to pollute the blue.

    Add a polariser to this and you can end up with the sky almost black (you effectively have a luminance control of the blue channel with your polariser).

    Reflections from waves will alternately reflect the black, polarised sky and possible areas of non-polarised sky (and maybe transparent areas showing the green of the water).

    Tim

    p.s. Dana Lake is at 11,100 ft

  43. #193
    Senior Member pegelli's Avatar
    Join Date
    Dec 2010
    Location
    Belgium
    Posts
    2,119
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by ErikKaffehr View Post
    Hi Tim,
    Something I noticed is that both Tim Ashley, Lloyd Chambers and myself apply quite a bit intensive sharpening, which is often combined with some masking. I have noticed with my settings that this can cause artefacts. Large amount of low radius sharpening enhances noise. The masking removes sharpening in parts of the image, causing the visible grain pattern to switch on and off. This can often be observed as grain pattern in contours along edges.

    In my humble opinion we are sharpening quite a lot at the pixel level which is really seldom optimal. Pictures are not intended to be viewed at the pixel level and prints probably need most sharpening in the low to medium frequencies, say 10-30 lp/mm on 135 film, where the contrast sensivity of human vision is highest. But, he who is without sin may throw the first stone, and that will certainly not be me…

    Best regards
    Erik
    Hi Erik, I think no sins are committed so no stones need to be thrown. But you raise an interesting point. I've learned most of my sharpening from reading a lot of material by Bruce Frazer and Jeff Schewe who tell us to do as little "capture sharpening" as possible and then do your creative and final sharpening specifically for the output size and medium you're preparing the file for (print or screen). Since the sharpening settings in Lightroom (and I think C1 as well) are "capture sharpening" I do those very mildly and not far from the default settings. Just enough to judge if a file is sharp enough to further process or not. This way I hardly ever have problems with exaggerating noise and/or orange peel effect. After export from LR to prepare the file for printing or web showing I do a final round of noise reduction (only when required) followed by output sharpening specific for the output size and medium. I like the results this workflow gives me and wonder what advantages you (and may be the others you mention) see in doing a very aggressive capture sharpening, since that tends to exaggerate noise and other artifacts that are present in the file. What do you think I am missing by doing only a very mild capture sharpening?

  44. #194
    Member
    Join Date
    Jul 2008
    Location
    Leeds, UK
    Posts
    127
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by ErikKaffehr View Post
    Hi Tim,

    From what I can see in the samples it is not entirely clear what phenomena are attributed to the "orange peel" effect and what is called posterisation.
    In search of this 'orange peel' phenomenon I downloaded the test raw files for D810 and A7R from DPReview's studio comparison and then processed them in rawdigger using 2x2 (pixel binning i.e. without raw demosaic'ing) and I can't find any difference between them. I used a test patch (third grey from the left) on the colourchecker target at the top of the image.

    The Sony's red/blue channels appear a little darker possibly but even accounting for that there is no difference.

    Anybody suggest I should look somewhere else for this orange peel?

    I'm also writing some software to analyse raw files to see if posterisation is causing visible differences (using delta E 2000 taken from a sample processed raw to compare with). Hopefully it will create a contour map of areas of posterisation (multiple contiguous pixels with identical numbers adjacent to another patch of multiple contiguous identical numbers). this can't guarantee picking up posterisation but it will point to possible areas to look at. It may make sense to correlate this with the delta compression values from rawdigger.

    This seems more common sense than guessing if something is a visible problem or not.

    Thoughts?

  45. #195
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    Tim orange peel seems to be related to ACR and LR as folks using C1 are not getting that effect. Not sure what is causing it myself but it seems related to sharpening in those programs.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  46. #196
    Senior Member Amin's Avatar
    Join Date
    Dec 2007
    Location
    Boston, MA (USA)
    Posts
    1,809
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Like Guy, I've never seen orange peel effects in files processed by C1. I have seen them in LR. However, Tim Ashley has seen orange peel from Sony files that were processed to TIFF without sharpening in C1 and then subsequently sharpened in LR, whereas he doesn't see it under any circumstances with D810 files. This is very interesting. I'd like to know what causes it.

    Once I get a break, I'm gonna do a lot of D810 - A7RII comparing. For me, all this stuff doesn't matter a whit for my photography. Artifact peeping is a separate hobby unto itself, but it's one I enjoy.
    Likes 1 Member(s) liked this post

  47. #197
    Member
    Join Date
    Jul 2008
    Location
    Leeds, UK
    Posts
    127
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Amin View Post
    Like Guy, I've never seen orange peel effects in files processed by C1. I have seen them in LR. However, Tim Ashley has seen orange peel from Sony files that were processed to TIFF without sharpening in C1 and then subsequently sharpened in LR, whereas he doesn't see it under any circumstances with D810 files. This is very interesting. I'd like to know what causes it.

    Once I get a break, I'm gonna do a lot of D810 - A7RII comparing. For me, all this stuff doesn't matter a whit for my photography. Artifact peeping is a separate hobby unto itself, but it's one I enjoy.
    Hi Guy/Amin,

    I'll have a look at both files post processed in L1 the same way and compare them with the actual raw data..

    Tim

  48. #198
    Member
    Join Date
    Aug 2015
    Posts
    20
    Post Thanks / Like

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Guy Mancuso View Post
    This is exactly my point all along.
    The file rendered into ProPhoto RGB is acceptably clean, needs only minor retouch on small spots, done in less than 4 minutes. The conversion to Adobe RGB, however, is the whole different story. Concentrating on the camera and shooting conditions shifts the accent into the wrong direction here.
    Thanks 1 Member(s) thanked for this post

  49. #199
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by timparkin View Post
    Hi Guy/Amin,

    I'll have a look at both files post processed in L1 the same way and compare them with the actual raw data..

    Tim
    Thanks Tim. It is really weird to be honest as I am not seeing that effect at all in C1. If I push sharpness really heavy for instance I may see more crosshair look but you really have to push it.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  50. #200
    Administrator, Instructor Guy Mancuso's Avatar
    Join Date
    Oct 2007
    Location
    Arizona
    Posts
    23,623
    Post Thanks / Like
    Images
    2555

    Re: Seeing any Posterization issues with A7r ll?

    Quote Originally Posted by Iliah Borg View Post
    The file rendered into ProPhoto RGB is acceptably clean, needs only minor retouch on small spots, done in less than 4 minutes. The conversion to Adobe RGB, however, is the whole different story. Concentrating on the camera and shooting conditions shifts the accent into the wrong direction here.
    Point taken. I guess the whole thing that throws this all in the air are the polarizer and the altitude than with color management issues, maybe some compression issues this file was just destined to fail. Some may want to blame one thing but I really just think its a combination of circumstances. Or maybe better said I could not take this file to Sony and say your compression scheme alone completely ruined it and that was kind of what was said. So I could not confront Sony based on what everyone has found. Its just not a single issue.

    Other files where compression was the issue. Absolutely present that to Sony this one Im sorry it would be wrong.

    Those are my thoughts. Right or wrong it would be uncomfortable for me at least given what we know now to blame one thing.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com
    Likes 2 Member(s) liked this post

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •