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Thread: ISO 800 - some Sinar eMotion 75 samples (2)

  1. #101
    Subscriber gogopix's Avatar
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    HOLD EVERYTHING!

    what's this Brumbaer's Co in the software EXIF entry?

    Does that mean there is noise reduction aleardy applied there?

    Then it is not in the raw.

    However, if it is just raw development, W/O NR then all above comments hold

    Theirry, which is it?

    Regards
    Victor

  2. #102
    thsinar
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    hi Victor,

    there is absolutely no NR applied during conversion into DNG. Read my previous post:during conversion, the centerfold effect is corrected (if selected), the colour balance is set (either a pre-saved default or one's own CB), and the reference file of the specific back is applied, nothing more.

    Thierry

    Quote Originally Posted by gogopix View Post
    HOLD EVERYTHING!

    what's this Brumbaer's Co in the software EXIF entry?

    Does that mean there is noise reduction aleardy applied there?

    Then it is not in the raw.

    However, if it is just raw development, W/O NR then all above comments hold

    Theirry, which is it?

    Regards
    Victor

  3. #103
    asabet
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    Quote Originally Posted by gogopix View Post
    I did open the file in C1 version 4 (whatever they are callingit) and the files are remarkable. I 'pushed' only 2.5 ev but still, Thierry you guys have something here.
    Very little noise even at 100% and pushed.
    Hi Victor,
    Glad you had a chance to have a look, and thanks for sharing how this looks in C1 4. Even if this RAW file had been cooked (NR incorporated) - and I accept Thierry's assurance that it hasn't - it would still be remarkable since the final product is an ISO 4800-6400 equivalent file with a far better detail/noise ratio than the fully processed results from any other camera I've seen at those ISOs with this shutter speed.
    Regards,
    Amin

  4. #104
    thsinar
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    Dear Amin,

    I can re-assure you on this: there is currently no NR possible in either eXposure or Brumbaer dng converters. NR will be incorporated in eXposure in a next version.

    Have a look at those applications.

    Best regards,
    Thierry

    Quote Originally Posted by asabet View Post
    Even if this RAW file had been cooked (NR incorporated) - and I accept Thierry's assurance that it hasn't - it would still be remarkable since the final product is an ISO 4800-6400 equivalent file with a far better detail/noise ratio than the fully processed results from any other camera I've seen at those ISOs with this shutter speed.
    Regards,
    Amin

  5. #105
    asabet
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    Hi Thierry,
    I wasn't doubting you, but thanks for the re-reassurance .
    All the best,
    Amin

  6. #106
    thsinar
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    It was actually meant for other(s).



    Thierry

    Quote Originally Posted by asabet View Post
    Hi Thierry,
    I wasn't doubting you, but thanks for the re-reassurance .
    All the best,
    Amin

  7. #107
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    Not sure things are as good as they seem...

    Thierry,

    I may be wrong here, but what I expect we are seeing with this file is that it actually takes a +3EV push to get us to an ISO 800 equivalent with the file you provided. It still happens to look very nice but it's not getting us to an ISO 6400 as we've assumed so far just ISO 800.

    I'm basing this statement on what I was seeing with Grahams sample files in this thread where he provided the same scene at ISO 50, 100, 200, 400 and adjusted shutter speed for each step up in ISO:

    http://forum.getdpi.com/forum/showthread.php?t=1723

    The difference between the ISO 50 and 400 shots took +3EV on the 400 shot to get to the equivalent brightness of the 50 shot.

    Your thoughts?

    Thanks,

    Greg

  8. #108
    thsinar
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    Re: Not sure things are as good as they seem...

    Dear Creg,

    I do not know who claimed that it was ISO 6400, but not me. All I have said is that I have shot this at ISO 800 and SLIGHTLY under-exposed (purposely).

    Best regards,
    Thierry

    Quote Originally Posted by Greg Seitz View Post
    Thierry,

    I may be wrong here, but what I expect we are seeing with this file is that it actually takes a +3EV push to get us to an ISO 800 equivalent with the file you provided. It still happens to look very nice but it's not getting us to an ISO 6400 as we've assumed so far just ISO 800.

    Your thoughts?

    Thanks,

    Greg

  9. #109
    asabet
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    I was the one who claimed that it was an ISO 6400 equivalent after being pushed 3 stops during RAW conversion. This is based on the file having been taken at a native ISO 800. Greg, are you suggesting that the file, processed at default exposure settings in a RAW converter, is an underexposed ISO 100 file (hence ISO 800 after pushing three stops)?

  10. #110
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    Re: Not sure things are as good as they seem...

    Quote Originally Posted by thsinar View Post
    Dear Creg,

    I do not know who claimed that it was ISO 6400, but not me. All I have said is that I have shot this at ISO 800 and SLIGHTLY under-exposed (purposely).

    Best regards,
    Thierry
    Thierry,

    I know you didn't claim ISO 6400, sorry if I implied that. I'm trying to understand if it's normal behavior for an ISO 800 shot to appear 3EV underexposed in the raw editors. I've tried with both Aperture and ACR and see the same thing - I have to bump up the EV by +3 to get to what I'm roughly guessing another camera would be showing with the same ISO, Aperture and shutter speed.

    Graham thought what was happening might be related to the Brumbaer conversion. Just trying to get your thoughts since I only have this one sample to go on for the eMotion 75. A series of ISO 100,200,400,800 halving the shutter for each subsequent shot on the eMotion 75 would answer the question I suppose.

    Thanks,

    Greg

  11. #111
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    Quote Originally Posted by asabet View Post
    I was the one who claimed that it was an ISO 6400 equivalent after being pushed 3 stops during RAW conversion. This is based on the file having been taken at a native ISO 800. Greg, are you suggesting that the file, processed at default exposure settings in a RAW converter, is an underexposed ISO 100 file (hence ISO 800 after pushing three stops)?
    Hi Amin,

    Yes, that's what I'm suggesting it behaves like in the raw editor. I only have Grahams files for the e54LV to go on but I'm guessing they behave the same. You might want to download his samples to see what I mean.

    Thanks,

    Greg

  12. #112
    thsinar
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    Re: Not sure things are as good as they seem...

    Greg,

    I know you didn't imply it was me. No harm.
    I honestly don't know how Stefan (Hess) does the conversion, but I know for sure that he does not apply any NR, even "behind the stage", for having spoken with his colleague who has helped him to write this tool (Rainer Viertlböck).
    Actually the Sinar eXposure does deliver a DNG which is right on the spot, concerning my exposure (slightly under) and with the exactly same noise level as the Brumbaer DNG.

    Eventually, it doesn't matter what happens, to me, only the end result is of interest, IMO. Even if the file would be 3 stops under and then pushed, what difference would it do? Actually, I am pretty happy of the result, when I see other samples published at this ISO setting.

    But if of interest I can do such a test on the whole ISO range with changing the shutter speed.

    Best regards,
    Thierry

    Quote Originally Posted by Greg Seitz View Post
    Thierry,

    I know you didn't claim ISO 6400, sorry if I implied that. I'm trying to understand if it's normal behavior for an ISO 800 shot to appear 3EV underexposed in the raw editors. I've tried with both Aperture and ACR and see the same thing - I have to bump up the EV by +3 to get to what I'm roughly guessing another camera would be showing with the same ISO, Aperture and shutter speed.

    Graham thought what was happening might be related to the Brumbaer conversion. Just trying to get your thoughts since I only have this one sample to go on for the eMotion 75. A series of ISO 100,200,400,800 halving the shutter for each subsequent shot on the eMotion 75 would answer the question I suppose.

    Thanks,

    Greg

  13. #113
    Senior Member Graham Mitchell's Avatar
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    Quote Originally Posted by Greg Seitz View Post
    Hi Amin,

    Yes, that's what I'm suggesting it behaves like in the raw editor. I only have Grahams files for the e54LV to go on but I'm guessing they behave the same. You might want to download his samples to see what I mean.

    Thanks,

    Greg
    It seems to be a peculiarity of Brumbaer. The actual exposure had a perfectly balanced histogram in my sample.

  14. #114
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    Re: Not sure things are as good as they seem...

    Quote Originally Posted by thsinar View Post
    Greg,

    I know you didn't imply it was me. No harm.
    I honestly don't know how Stefan (Hess) does the conversion, but I know for sure that he does not apply any NR, even "behind the stage", for having spoken with his colleague who has helped him to write this tool (Rainer Viertlböck).
    Actually the Sinar eXposure does deliver a DNG which is right on the spot, concerning my exposure (slightly under) and with the exactly same noise level as the Brumbaer DNG.

    Eventually, it doesn't matter what happens, to me, only the end result is of interest, IMO. Even if the file would be 3 stops under and then pushed, what difference would it do? Actually, I am pretty happy of the result, when I see other samples published at this ISO setting.

    But if of interest I can do such a test on the whole ISO range with changing the shutter speed.

    Best regards,
    Thierry

    Thierry,

    That's good to know, so it sounds like it's related to the Brumbaer conversions. It helps clarify what we're looking at in the file.

    Thanks,

    Greg

  15. #115
    thsinar
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    Re: Not sure things are as good as they seem...

    no problem, Greg, I am learning to, and find it great to be able to communicate openly.

    Best regards,
    Thierry

    Quote Originally Posted by Greg Seitz View Post
    Thierry,

    That's good to know, so it sounds like it's related to the Brumbaer conversions. It helps clarify what we're looking at in the file.

    Thanks,

    Greg

  16. #116
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    Coming back to this party a bit late....

    This issue about exposure is what got things started. In the shot that Thierry provided, going through the Brumbaer conversion, the image, pulled up in a number of apps (Aperture, ACR/PS, C1, Raw Developer), all have a rather dark appearance. They also show about +1EV boost in what would be "brightness", as a collective term. They all tolerate or need another +2EV boost in "Exposure" in each of the tools to get what appears to be a properly exposed image.....at least to my eyes and on my screens.

    So the entire issue becomes what is the real correct exposure? Is the file simply a very underexposed (3EV) 100 ISO shot, or a true ISO 800 shot? I was reading Amin's comments about ISO 6400 coming from the assumption that the file was a true ISO 800 exposure, and that it could then tolerate an added +3EV push.

    I do not think anybody is doubting anybody else here, and as Thierry mentions, the goal is really to figure out what is happening and just how clean the higher ISO shots are from the Sinar back. The shots that Graham posted had a similar situation. The ISO 800 shots looked liked more like an ISO 100 shot that had been underexposed by 3EV or so, and when pushed to what appears to be a more correct looking image, they start to display a bit more noise than the shot Thierry shared with us.

    After reading things above, I still come to a conclusion that there is something in the Brumbaer conversion that appears to render the images at a more "native" ISO 100 rating, and that everything else is pushed from there. The performance of the files is still really incredible, but it would be nice to know that when one sets the camera/back to ISO 800, are they really getting a more true ISO 800 reading, or just an ISO 100 reading that then gets a +3EV push?

    Does that make sense, or am I just adding confusion to all of this?

    LJ

    P.S. I will add that my last paragraph is sort of what does happen with most other cameras and how they expose things. Only difference is that the files tend to display as properly exposed when viewing, and not needing the added EV boost. There is a loss of DR and contrast in the higher ISO renderings, plus noise starts to come in, just as expected. I believe all sensors expose at their "native" design ISO, and that things get pushed from there in the camera processing engines that spit out the files.
    Last edited by LJL; 13th May 2008 at 09:10.

  17. #117
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    easy to sort out, was the original exposure reflected/in camera or was the exposure incident/from meter?

    if this is from in-camera metering then the dark subject is fooling the meter into adding exposure. When it was shot deliberately under you are left with a result that is probably what an incident meter would have yielded from the get go.

    ISO is something in digital that we don't have good norms for, at least to my knowledge. IOW, shoot an 18% grey card under this light, what do you get? 128,128,128? It is dependent on the gamma also of the capture space.

    Interesting to look at the histogram, it is pushed all the way left. But if you turn on the clipping display, setting black to 0, exposure to 0, contrast to zero and brightness to 25 there is nothing clipped. it is a very dimly lit soft picture. Part of that has something to do with it imo. the light is actually very soft and even, and all of the exposure is in the green channel, the best channel.

    regardless of above, it seems extraordinarily good.

    I have pushed M8 files shot at 160 three stops and they look much better than you would expect. But that is dependent on the source lighting, which usually has to be soft and even, like we have here. But pushing 640 is not going to look like this...

  18. #118
    Senior Member Graham Mitchell's Avatar
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    Guys, I am about to start a new thread which should clear all of this up. Give me a few minutes.

  19. #119
    thsinar
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    hi Robert,

    Concerning "ISO":

    I had actually mentioned/written about the definition of the "ISO" in another post. Here what it reads:

    --------------------------------------------------------------------------------------
    The first question one has to ask, is to what the actual (nominal) ISO is corresponding and related. There are of course ISO norms, but those are rather thought for the consumer field and leave open a big "playing gap". Therefore, the manufacturer has to decide by himself to what this ISO should be related.

    When doing a lightmetering, the result should lead to a medium grey (Lab 50/0/0) rendered as medium grey. One has to be aware here, that a RGB medium grey does not necessarily correspond to 128/128/128, respectively a centered histogram does not necessarily lead to a correct exposure.

    This is strongly depending on the Gamma value of the chosen Colour Working Space: in sRGB, a RGB value of 119/119/119 correspond to a medium grey. In ECI RGB, a medium grey is given with a value of 101/101/101.

    The goal of the ISO sensitivity "finding" should therefore be to reach the above value for a medium grey, with ALSO taking in count the used "contrast curve". This has lead to the value of ISO 100 as nominal sensitivity for the eMotion 75, and ISO 50 for the eMotion 54 (resp. eMotion 22), with a "default" or "standard" contrast curve of "3" in Captureshop/eXposure.
    --------------------------------------------------------------------------------------

    To answer your question: the metering was done with the histogram and with my experience of using a histogram. It has been a long time since I have used a light-meter, not even used the camera meter. I was taking care that the highlights were not over-saturated by using the "warning feature". I did take real care for my highlights and make sure to get some details in it, which "pushes" the whole to the left by about 1 stop, not more.
    So I did not let the camera meter fool me!

    I can say and guaranty you that the light was not soft at this time of the morning, and you can actually see it from the light falling on the subject: I have said that it was sunrise, still not full daylight, with the sun nearly at the horizon hitting the leaves with a flat angle. Actually, and out of my own interest, I did measure the contrast with a Minolta spotmeter this last Sunday morning, at the very same time: if am remember right, there were 12 1/3 stops between the brightest highlight on one of the leaves and the shadows in the base of the foreground leaves. But I shall re-meter it when back home, to be sure. In any case, I don't think that one can categorize this situation as a low-contrast light situation.

    In any case, I do not wish here to start arguments and a fight, and am scared it goes this way, with comments like "it was lit in the best channel, the green color channel". It happens that the leaves in my garden are green, sorry about that. But the blacks are black and the highlights are highlights, and the shadows are there to show noise, if there is. which was important to me.

    With these words I wish you all a good day or good night, am leading to some rest.

    Best regards,
    Thierry

    Quote Originally Posted by robertwright View Post
    easy to sort out, was the original exposure reflected/in camera or was the exposure incident/from meter?

    if this is from in-camera metering then the dark subject is fooling the meter into adding exposure. When it was shot deliberately under you are left with a result that is probably what an incident meter would have yielded from the get go.

    ISO is something in digital that we don't have good norms for, at least to my knowledge. IOW, shoot an 18% grey card under this light, what do you get? 128,128,128? It is dependent on the gamma also of the capture space.

    Interesting to look at the histogram, it is pushed all the way left. But if you turn on the clipping display, setting black to 0, exposure to 0, contrast to zero and brightness to 25 there is nothing clipped. it is a very dimly lit soft picture. Part of that has something to do with it imo. the light is actually very soft and even, and all of the exposure is in the green channel, the best channel.

    regardless of above, it seems extraordinarily good.

    I have pushed M8 files shot at 160 three stops and they look much better than you would expect. But that is dependent on the source lighting, which usually has to be soft and even, like we have here. But pushing 640 is not going to look like this...

  20. #120
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    no worries, it is an extraordinary result no matter what.

    no one ever gets patted on the back for doing tests

    thanks for putting it out there, and the ISO definitions and methodology.

  21. #121
    asabet
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    Re: ISO 800 - some Sinar eMotion 75 samples (2)

    Sorry for introducing some incorrect thinking in this thread. Others who find this thread on a search later will also want to see this other thread Graham started. Regards, Amin

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