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Thread: P25 Plus noise test/ Very Boring sorry

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    Re: P25 Plus noise test/ Very Boring sorry

    Okay some raws from the kitchen . This one is full tungsten light at ISO 800

    http://www.yousendit.com/transfer.ph...5AFBB43EE5E974

    and this one is from earlier in the day with mixed lighting at ISO 800

    http://www.yousendit.com/transfer.ph...E78D4A4A1FC471
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    Re: P25 Plus noise test/ Very Boring sorry

    Downloaded your images and developed them in RAW Developer with NR set to zero. The noise is there but it's pretty darn good for the conditions.

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    Re: P25 Plus noise test/ Very Boring sorry

    Thanks David and with better light it may not even be noticed
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Guy,

    Appreciate you posting these.

    Here's one of your ISO 800 shots with 0 Lumi/Color noise in C1 everything else at default except wb. After developing I added a bit of Noiseware reduction in photoshop.

    By the way Guy, your 100% crops are actually 50% for some reason in all of these posts. This one is a 100% crop.

    Greg
    Last edited by Greg Seitz; 14th October 2010 at 07:22.

  5. #55
    thsinar
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    Re: P25 Plus noise test/ Very Boring sorry

    Guy,

    I have downloaded the files, but they are not RAWs, but TIF files. Anyway to get access to a real raw or DNG? Sorry, I don't really know how C1 handle files out of the Phase back: what goes in and what comes out?

    Thanks,
    Thierry

    Quote Originally Posted by Guy Mancuso View Post
    Okay some raws from the kitchen . This one is full tungsten light at ISO 800

    http://www.yousendit.com/transfer.ph...5AFBB43EE5E974

    and this one is from earlier in the day with mixed lighting at ISO 800

    http://www.yousendit.com/transfer.ph...E78D4A4A1FC471

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    Re: P25 Plus noise test/ Very Boring sorry

    Actually looks pretty good. I blowup to 100 percent and take a section from it. There all done approximately the same though
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by thsinar View Post
    Guy,

    I have downloaded the files, but they are not RAWs, but TIF files. Anyway to get access to a real raw or DNG? Sorry, I don't really know how C1 handle files out of the Phase back: what goes in and what comes out?

    Thanks,
    Thierry
    There Raw file extension is .tif i would have preferred something else myself because it can be confusing in filing
    Photography is all about experimentation and without it you will never learn art.

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  8. #58
    thsinar
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    Re: P25 Plus noise test/ Very Boring sorry

    Thanks Guy,

    it is indeed very confusing.

    Kind regards,
    Thierry

    Quote Originally Posted by Guy Mancuso View Post
    There Raw file extension is .tif i would have preferred something else myself because it can be confusing in filing

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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by Guy Mancuso View Post
    Actually looks pretty good. I blowup to 100 percent and take a section from it. There all done approximately the same though
    Noiseware cleans up the chroma noise very nicely.

    Check my crop against post #23, you'll see the size difference. Is it possible that your develop settings in C1 are set to 50%?

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    Re: P25 Plus noise test/ Very Boring sorry

    Hmmm i have it set at 100 percent but just noticed my resolution is 360 not 300 maybe the case here Greg .
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Greg is this the program you are using

    http://www.imagenomic.com/nwpg.aspx?...FRcaagodfEyXiQ
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by Guy Mancuso View Post
    Greg is this the program you are using

    http://www.imagenomic.com/nwpg.aspx?...FRcaagodfEyXiQ
    Yes, the Pro version.

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    Re: P25 Plus noise test/ Very Boring sorry

    Great the results look good and the Pro version looks like you can just run a action. Downloading a demo right now
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    If you end up wanting to buy it, PM me, I might have a 20% coupon.

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    Re: P25 Plus noise test/ Very Boring sorry

    Thanks Greg just downloaded the demo so it puts grids on the image and I just used the default which maybe too much but anyway lets see without than with noiseware. Now i turned everything off in C1 all set to zero
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Just for comparison this is ISO 100
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Even though a slight loss in detail we are talking a 4 stop difference here. Hell that is damn good
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Capture One 4.1.X (also C1 3.7.X) has one major technical advantage over any other means of noise reduction when used with a phase one back: it uses data from the dark-slide exposure. Anytime you change shutter speed the back records a dark-slide exposure which maps where and how heat and interference are effecting the CCD. This is most noticeable in long exposures and to some extent high-ISO shots.

    While I prefer the look of the noise reduction in C14 to anything else I've seen this is largely a personal aesthetic choice. Even if you prefer the look you get from a third party noise reduction tool I would suggest doing a minimal amount of noise reduction in Capture One to take advantage of the dark slide information before processing in 16-bit finishing the noise reduction in that third party software. This is similar to my suggested sharpening workflow of doing minimal pre-sharpening in C14 where micro-detail can best be rendered, and then doing print-sharpening in either PS or your preferred 3rd party sharpening/enlargement program.

    Finally, WB and light-source-color can have a dramatic effect on noise. If you're shooting in yellowish light (e.g. outdoors at night with street lights) then the blue pixels on the CCD are going to be drastically underexposed. White balancing a heavily yellow photo to be more neutral is, in fact, just a fancy way of boosting the effective ISO of the blue channel. This is one of the reasons why MFDBs are going to outperform even the best dSLRs in harsh lighting situations (contrast and weird color temperatures) which push dynamic range, shadow recovery, and bit depth to the limit. I've seen noisy images from dSLRs which only needed noise reduction on the blue channel to be usable again, just don't do that to an extreme or you'll get blue halos around sharp shadow-to-midtone transitions.

    Doug Peterson
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    Senior Member EH21's Avatar
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    Re: P25 Plus noise test/ Very Boring sorry

    Doug,
    Thanks for the info - now I have 2 questions for you. Is there a native WB of the Phase backs - in other words is there an optimum color temperature for lighting? Second question, will I see less noise if I set the WB in camera prior to the exposure rather than after in post?

    Thanks,
    Eric

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    Re: P25 Plus noise test/ Very Boring sorry

    Eric great questions. I am sitting right across from Doug and he is tied up at the moment so he asked I send back a reply.
    In regards to the native WB temp that is a very good question, he is investigating that.
    On the second one the WB that is being applied is to the preview of the RAW not the file itself so it should make no difference where you WB it.
    Lance Schad
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    Re: P25 Plus noise test/ Very Boring sorry

    After further playing around , I honestly just like lowering the luminance in C1 and maybe playing around with color to get some of that taken care of. This is at the 800 setting which i don't expect to use often but nice to have it and see some nice results from it. I think we need to remember also is will we really see it in print and I am on a project right now for the next two weeks doing a book but i will explore that some more with my 3800. Lance sent me a 28mm this weekend to play with so I want to try that first and start playing around again with the P25 plus and get a little more used to working with it but so far i love the files and working with this back. images are just looking so nice and I need to get this on a real job and get it going. Been a little slow there
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Guy,
    One other recommendation for you for P25+ ISO 800 files when using C1... when turing down the luminance noise IMHO you can also get a better looking file by also decreasing the standard sharpening. If you haven't already played with this, give it a go, because the standard sharpening also tends to sharpen the grain which again IMHO does not improve the image.
    Eric Hiss

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    Re: P25 Plus noise test/ Very Boring sorry

    Yes and i had that up slightly in all of these files so when i hit the 800 i can reduce that a touch and actually lower the noise more. that is something I will also play with this weekend
    Photography is all about experimentation and without it you will never learn art.

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  24. #74
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    Re: P25 Plus noise test/ Very Boring sorry

    Guy,

    1. when processing in C1, do you need to adjust the exposure (or brightness, or how ever C1 calls this) of the higher ISO shots, and if yes, by how much?

    2. do you mind posting the lower ISO raws too to either CF000040 or to CF000064?

    Thanks
    Gabor

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    Re: P25 Plus noise test/ Very Boring sorry

    Bathroom the exposure was slightly under overall and the Kitchen is actually pushed up a little but I did not play with any shadow recovery because that would throw things off and that would bring in other issues. So if anything just brought up the exposure . I think the kitchen was 3/4 of a stop so more like 1250 but I would rather not say that as completely accurate . C1 things look a little darker than LR so who is correct is the question. I need to find those files if I even kept them. I'm a clean freak sometimes with files and usually don't keep test files around
    Photography is all about experimentation and without it you will never learn art.

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  26. #76
    thsinar
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    Re: P25 Plus noise test/ Very Boring sorry

    Guy,

    it would really be nice to see these files, as raw as possible. I did download your TIFs but these are definitively no raws.

    Is there no way to get "rawer" out of the back?

    Thanks and best regards,
    Thierry

    Quote Originally Posted by Guy Mancuso View Post
    Bathroom the exposure was slightly under overall and the Kitchen is actually pushed up a little but I did not play with any shadow recovery because that would throw things off and that would bring in other issues. So if anything just brought up the exposure . I think the kitchen was 3/4 of a stop so more like 1250 but I would rather not say that as completely accurate . C1 things look a little darker than LR so who is correct is the question. I need to find those files if I even kept them. I'm a clean freak sometimes with files and usually don't keep test files around

  27. #77
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    Re: P25 Plus noise test/ Very Boring sorry

    Guy,

    your CF000040 was three stops underexposed, CF000064 even more. I mean with "underexposed" compared to the maximum exposure without clipping (except for the lamps, their center has been clipped ic CF000062).

    This makes me think that the P25 Plus does not have different ISOs, just like the Sinar 54 (unlike the P45 Plus, which does have different ISO gains.

    I can tell this with certainty only if I see raw files with a serie of ISOs; same scenery, same lighting.

    Thierry,

    those TIFs are pretty raw. You can open them with ACR (in Photoshop or Lightroom).

    Gabor

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    Re: P25 Plus noise test/ Very Boring sorry

    There out of the camera, how raw can you get.
    Photography is all about experimentation and without it you will never learn art.

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  29. #79
    thsinar
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    Re: P25 Plus noise test/ Very Boring sorry

    Dear Gabor,

    yes, I have seen that one can open them, and noticed the same under-exposure.

    Thanks,
    Thierry

    Quote Originally Posted by Panopeeper View Post
    Thierry,

    those TIFs are pretty raw. You can open them with ACR (in Photoshop or Lightroom).

    Gabor

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    Re: P25 Plus noise test/ Very Boring sorry

    Here are a ton from the other day . Look in the jack download here

    http://idisk.mac.com/guymancuso-Public?view=web
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by Panopeeper View Post
    Guy,

    your CF000040 was three stops underexposed, CF000064 even more. I mean with "underexposed" compared to the maximum exposure without clipping (except for the lamps, their center has been clipped ic CF000062).

    This makes me think that the P25 Plus does not have different ISOs, just like the Sinar 54 (unlike the P45 Plus, which does have different ISO gains.

    I can tell this with certainty only if I see raw files with a serie of ISOs; same scenery, same lighting.

    Thierry,

    those TIFs are pretty raw. You can open them with ACR (in Photoshop or Lightroom).

    Gabor
    So how are you measuring the underexposure . If there were that dark don't you think i would see that in C1 , LR or on the LCD screen or the histogram. If that is the case than every P25 file out there is 3 stops under. This makes no sense. You can't go by some of the highly reflective metal either
    Photography is all about experimentation and without it you will never learn art.

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  32. #82
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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by thsinar View Post
    yes, I have seen that one can open them, and noticed the same under-exposure
    Thierry,

    you can see the magnitude of underexposure in ACR only by applying -2 EV "exposure" correction, because ACR applies automatically +2 EV. Note, that this does not show up on the slider.

    Quote Originally Posted by Guy Mancuso View Post
    Here are a ton from the other day . Look in the jack download here
    Guy,

    all those are ISO100.

    Gabor

  33. #83
    thsinar
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    Re: P25 Plus noise test/ Very Boring sorry

    Yes Gabor, that is my understanding. I have one question, related to this "automatic +2" applied by ACR: how is this managed/controlled in ACR, based on what criteria?

    Thanks and best regards,
    Thierry

    Quote Originally Posted by Panopeeper View Post
    Thierry,

    you can see the magnitude of underexposure in ACR only by applying -2 EV "exposure" correction, because ACR applies automatically +2 EV. Note, that this does not show up on the slider.

    Gabor

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    Re: P25 Plus noise test/ Very Boring sorry

    I will run a new test today of the bathroom. My one issue is i have a old AFD loaner body that is not very well behaved and some images are a stop under. I will shoot the bathroom over. The Kitchen is a tough nut to shoot without lights because of reflections and highlights. I will post the raws to my public folder later today and let you know when they load , takes forever to load.
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Did this over again this time right on the money for expousre on the macbeth and right side of frame left side just a touch of blowing out from the window , did not adjust anything. Luminance at 10 color at 51 and lowered the sharpening down

    100
    200
    400
    800

    Full shot ISO 100 . I will post the 4 raws in a little bit here
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    Re: P25 Plus noise test/ Very Boring sorry

    Those settings are pretty much to achieve the best sharpness with Luminance at 10. But I would most likely go a touch higher to smooth a little more
    Photography is all about experimentation and without it you will never learn art.

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    Re: P25 Plus noise test/ Very Boring sorry

    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  38. #88
    Panopeeper
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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by Guy Mancuso View Post
    So how are you measuring the underexposure
    From the maximum possible exposure backwards, based on the non-demosaiced raw data. "Underexposure" is certainly not the correct term. If the exposure is for example 1/2 EV from the very right, that does not mean that the shot is in fact underexposed.

    Anyway, I don't know any better term for this. "Perfect ETTR minus 3 EV" is correct, but a little bit too long.

    If there were that dark don't you think i would see that in C1 , LR or on the LCD screen or the histogram
    ACR is automatically adjusting the exposure of the ISO 800 shots by +2 EV, the ISO 400 by +1 EV and the ISO 100 by -1 EV. I guess C1 is doing that as well, as is the camera's firmware.

    If that is the case than every P25 file out there is 3 stops under
    Only the ISO 800 shots, if you meter correctly. I went through your shots CF000127-CF000145. All are ISO 100, and most of them are well exposed:

    CF000127: -2 2/3 EV
    CF000128: -1 1/3 EV
    CF000129: -2/3 EV
    CF000130: -1/3 EV
    CF000131: -1 EV
    CF000132: -1 EV
    CF000133: -2/3 EV
    CF000134: perfect ETTR
    CF000135: perfect ETTR
    CF000136: perfect ETTR
    CF000137: -1/3 EV
    CF000138: -1 EV
    CF000139: -1/3 EV
    CF000140: -1 EV
    CF000141: -1/3 EV
    CF000142: -1/3 EV
    CF000143: -1/3 EV
    CF000144: -1/3 EV

    (Some *tiny* clippings due to reflections and turned on light bulbs occured in several shots; I qualified those too as "perfect ETTR".)

    Now, let's see the exposure of the ISO serie 100-400, CF0000251-CF000254:









    The ISO 100 shot is almost perfectly exposed (only 1/3 EV down from the max). However, the pixel values went down with the exposure, stop by stop (the thick white bars under the graphs mark one stop, the thin ones mark 1/3 stop). With ISO gain the pixel values would remain roughly on the same level, i.e. there was no ISO gain.

    Using higher ISO is equivalent to a negative exposure bias regarding the raw data. The reason to use different ISOs with this camera is only to see an adjusted preview in-camera and the embedded JPEG image.

    In other words, you must not use ISO as a compensation for exposure.

    Btw, I do not know, why ACR regards ISO 200 as "native" (i.e. it does not adjust the exposure automatically).

    Another aspect: ACR increases the noise reduction as the ISO increases. This too remains hidden from you.

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    Re: P25 Plus noise test/ Very Boring sorry

    Did you check the new raws from the bathroom with 100,200,400 and 800. Now i have to say from a shooters point of view , I think all we care about is ISO 400 and 800 going to look good. But i understand we should know the science behind it but at the end of the day that would be the bottom line. Now i don't know about what ACR and C1 are doing as these images come in the door. Have you tried bringing these in C1
    Photography is all about experimentation and without it you will never learn art.

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  40. #90
    Panopeeper
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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by Guy Mancuso View Post
    Did you check the new raws from the bathroom with 100,200,400 and 800
    CF0000251-CF000254 are the bathroom shots (I posted their raw histograms above).

    Now i have to say from a shooters point of view , I think all we care about is ISO 400 and 800 going to look good. But i understand we should know the science behind it but at the end of the day that would be the bottom line
    Guy, there is no scienece here (until now). There is no ISO 400 and 800 (not even 200) in this camera, that's all I am saying. When using higher ISO than 100, you are simply underexposing.

    The difference between plain underexposure and underexposure with ISO gain is, that the noise would be lower with ISO gain. I could demonstrate that, but I don't feel anyone here is keen to see that.

    You may be happy with the noise after noise removal, but that costs fine details.

    Now i don't know about what ACR and C1 are doing as these images come in the door. Have you tried bringing these in C1
    I don't have C1; I looked at them in raw format and in ACR.

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    Re: P25 Plus noise test/ Very Boring sorry

    It sounds interesting but I don't think I'm picking up what you're putting down... What do you mean when you say the camera (presumably back) doesn't have ISO above 100 and that the higher settings are simply "underexposures". How does this differ from a camera that, for lack of a better vocabulary, has a "true" ISO 200 (or higher).

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    Re: P25 Plus noise test/ Very Boring sorry

    He's saying that back manufacturers apply a gain tag to any ISO shot over the back's native ISO, which is applied during the raw conversion stage. Since pumping exposure also increases noise, the raw converter also applies some proprietary noise reduction when it sees the tag. While this may in fact be the case, it is a phenomena of ALL digital sensors and cameras, not just MF DB's; The Leica M8 does this, the Nikon D3 does this and the Canon 1Ds3 does this.

    ALL sensors have a single, native ISO and it is raw processing that allows for USABLE higher ISO functionality. So the important factor in my mind, is simple: How good does the processing software do this job? If I get an ISO 800 exposure that looks as low noise as Guy's bathroom shot above while maintaining that much detail, I am a very happy camper! Moreover, when sized to match and compared as prints, the latest generation of MF DB offers a significantly better "noise" signature than any DSLR at similar ISO, at least in my opinion and for my uses.

    Cheers,
    Jack
    home: www.getdpi.com

    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

  43. #93
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    Re: P25 Plus noise test/ Very Boring sorry

    Thanks for clearing that up... it's kind of what I thought but couldn't express. Seems like we're back where we should be... if the image looks good than how it got there is only of theoretical importance. Would I be correct in assuming that a back with a higher native ISO is more likely to generate a better high ISO image. If so, then this might be a question that prospective back purchasers should ask.

  44. #94
    Administrator, Instructor Guy Mancuso's Avatar
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    Re: P25 Plus noise test/ Very Boring sorry

    Interesting that the P25 plus came in at the native ISO at 200. i wonder if the P30 plus is actually at ISO 400 there native ISO. Finally i got my arms around this a little, been working too hard on this book project and too much espresso. LOL
    Photography is all about experimentation and without it you will never learn art.

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  45. #95
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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by David K View Post
    Seems like we're back where we should be... if the image looks good than how it got there is only of theoretical importance.
    Precisely

    Would I be correct in assuming that a back with a higher native ISO is more likely to generate a better high ISO image.
    Sure. (BUT...) It will depend a lot on the physics of the native sensor. For example, how hot the sensor was at capture will have a significant effect on total noise, and total noise gets amplified exponentially as gain is applied. This is where I believe the technological advances in higher ISO performance are occurring. Manufacturers are figuring ways of capturing images using less power, therefore keeping sensors cooler and thus generating less noise -- along of course with obtaining improved battery life. Other active cooling methods are likely in play too, especially for sensors that allow long capture times...

    Cheers,
    Jack
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  46. #96
    Panopeeper
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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by David K View Post
    It sounds interesting but I don't think I'm picking up what you're putting down... What do you mean when you say the camera (presumably back) doesn't have ISO above 100 and that the higher settings are simply "underexposures". How does this differ from a camera that, for lack of a better vocabulary, has a "true" ISO 200 (or higher).
    Digital sensors do not have different light sensitivities; they capture photons and "count" them. Unfortunately, this "counting" is not an accurate process. I tried to describe this in Post #55. In short, ISO gain means, that the sensor tries to get more detailed data from the same electric charge, though this is inherently less accurate, i.e. more noisy.

    When you underexpose a shot and "correct" it in raw processing, for example by the "Exposure" slider of ACR, the raw processor simply multiplies the original raw values. +1 EV causes a multiplication by two. The noise (irregularity) gets multiplied by two as well; thus, areas, which were too dark, now appear brighter - but noisier.

    The ISO gain is noisy as well, but to a lesser degree. When increasing the ISO by one stop, the pixel values get roughly doubled, but the noise is less than doubled. With higher and higher ISO, the "noise gain" increases, to a point, where the ISO gain is not better than simply multiplying all pixel values. Some cameras offer even higher ISO settings, but they simulate the effect by multiplying the values in-camera, just like in raw processing these are "fake ISOs".

    Quote Originally Posted by Jack Flesher View Post
    it is a phenomena of ALL digital sensors and cameras, not just MF DB's; The Leica M8 does this, the Nikon D3 does this and the Canon 1Ds3 does this
    It is not a common phenomenon for all digital sensors, not even for MFDBs. I know definitively, that the Phase One P45 Plus does have real ISO gain.

    Let's see the difference between the ISO effects of these two cameras.

    First, two captures from the P45+; the first is with ISO 400, shutter 1/80s, aperture f/5; the second with ISO 800, shutter 1/80s, aperture f/7.1.

    I selected a small area (marked by the orangy rectangle), which is uniformly colored and smooth, thus the noise can be easily measured in term of standard deviation per color.

    The red, green and blue pixel averages in the seelcted area are marked by yellow, the standard deviations by magenta.

    The average raw pixel values are very close despite the one stop lower exposure of the ISO 800 shot, i.e. the values are roughly doubled (the f/7.1 shot captured only half the photons compared to the f/5 shot). However, the noise is much less than doubled.





    Now let's see the comparable P25+ shots. The first is ISO 400, 1/8s, f/13, the second is ISO 800, 1/15s, f/13. I applied +3 EV respectively +4 EV brightness adjustment in the display; this does not affect the raw pixel values, only the RGB.

    As the exposure was halved without ISO gain, the second shot shows much lower pixel values (somewhat less than the half of those in the ISO 400 shot). However, the noise is much more than half of that in the ISO 800 shot due to the low exposure (this shot is almost 3 EV from the right edge, as shown by the histogram above).

    When the pixel values get doubled in raw processing, the noise gets doubled as well, and that will be much more, than it was in the ISO 400 shot.





    Please ignore the appearance of noise on these images, they are GIFs. This layered TIFF file contains the sceen captures without the deterrioration caused by GIF.

    An important note: one might think based on these shots, that the noise of the P25+ at ISO 400 is less, than that of the P45+. This comparison is not valid; the P45+ shot can be compared only to the other P25+ shot, because the P45+ ISO 400 shot is already with two stops ISO gain!

    the Nikon D3 does this and the Canon 1Ds3 does this
    All present DSLRs I have analyzed (two-three dozens) have real ISO gains, but many, perhaps most of them support even higher settings, and those settings are numerical dervatives, done in-camera, which is useful for JPEG only. For example the Nikon D3's highest true ISO is 6400.

    the latest generation of MF DB offers a significantly better "noise" signature than any DSLR at similar ISO, at least in my opinion and for my uses
    I can hardly debate your uses, but from the present shots is clear: the P25+ has a very good noise characteristic at ISO 100, but the lack of real ISO gain is visible when underexposed.

    The consequence of all the above is, that "higher ISO" should be used with the P25+ only when the exposure can not be increased at all, not as a substitute for higher exposure.

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    Re: P25 Plus noise test/ Very Boring sorry

    Maybe I am misunderstanding you as well... The only difference is where (when and how) in the process the gain is applied. You either crank up chip voltage or amplify the chip's base signal after capture, right? Bottom line is either method generates more noise than native and needs to be dealt with somewhere. At the end of the day, if whatever system being used generates an acceptable result for the end user's needs, what difference does it really make?

    The little bit of noise showing in Guy's P25+ ISO 800 example would be acceptable to me in many situations, and is certainly better than my 5D or 1Ds3 I tested was at 800. At 400, I can hardly see any objectionable noise in the P25+ example above. I should have my P45+ in a few days and I will post similar examples for us all to compare. My impression in Puerto Rico after the casual comparison Guy and I did there was that the P25+ did a little BETTER job on noise at 800 than the P45+ on the same image.

    What I think the more relevant discussion would be, is how this affects the total DR...
    Jack
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  48. #98
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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by Jack Flesher View Post
    The only difference is where (when and how) in the process the gain is applied
    Somewhat oversimplified, but one can think of it this way (the kind of digital representation of numbers has nothing to do with their meanings):

    if you have a number and multiply it by two, the low-order bit becomes zero in binary representation; i.e. the information does not increase by the multiplication. This is, what is happening in the raw processing, when applying +1 EV exposure adjustment.

    On the other hand, with ISO gain, the low order bit becomes meaningful; it carries the differences between different shades, making dark details distinguishable.

    This gain may be close to perfect at low ISOs with a good camera; at higher ISO it becomes more and more often unreliable, i.e. noise. Some cameras offer high ISO gain, but it is virtually useless, not better than simply multiplying the values gained by a lower ISO.

    Bottom line is either method generates more noise than native and needs to be dealt with somewhere
    Yes, but it is not irrelevant, if the noise doubles or inclreases to a smaller degree when reducing the exposure by one stop.

    At the end of the day, if whatever system being used generates an acceptable result for the end user's needs, what difference does it really make?
    Of course; I did not mean to communicate, that the P25+ does not have its place. If you are shooting in settings, where the illumination is usually not a problem, then this camera may be perfect for you. However, users have to be aware of the fact, that cranking up the ISO with this camera does not yield the same result as with a camera, which offers true ISO gain.

    I do not know, which other MFDBs (beside the P45+) offer real ISO gain; perhaps the fake ISO is the norm with MFDBs and the P45+ is the exception. I can determine this only based on comparable shots with different ISOs, like the Guy's bathroom set; I don't have such from any other MFDB.

  49. #99
    thsinar
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    Re: P25 Plus noise test/ Very Boring sorry

    Hi Jack,

    No, that is not so with Sinar: I have explained and confirmed a few times that there is ABSOLUTELY NO noise reduction filtering taking place before or during the DNG conversion in either the Sinar eXposure or the Brumbaer Converter.

    I cannot speak for other brands or other MFDBs, but I can assure you about Sinar's DNGs: no noise reduction applied at this stage at all.

    Quote Originally Posted by Jack Flesher View Post
    He's saying that back manufacturers apply a gain tag to any ISO shot over the back's native ISO, which is applied during the raw conversion stage. Since pumping exposure also increases noise, the raw converter also applies some proprietary noise reduction when it sees the tag. While this may in fact be the case, it is a phenomena of ALL digital sensors and cameras, not just MF DB's; The Leica M8 does this, the Nikon D3 does this and the Canon 1Ds3 does this.

    Cheers,

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    Re: P25 Plus noise test/ Very Boring sorry

    Quote Originally Posted by Jack Flesher View Post
    My impression in Puerto Rico after the casual comparison Guy and I did there was that the P25+ did a little BETTER job on noise at 800 than the P45+ on the same image.
    Is there any way we can get the same shot from each of these backs and Gabor can show us whether this is technically true or not?

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