LetTheRightLensIn said:
jrista said:
dtaylor said:
We are now WELL into the era of significantly improved DR.
Basically 12+ vs. 13+ stops. The DR meme is driven entirely by BS DxO tests that aren't even physically possible (i.e. claims of >14 stops from a 14-bit ADC).
Actually, it's more like 10.x stops vs. 13.x stops. I agree, DXO's PrintDR numbers are BS. Just use DXO's ScreenDR numbers, which are
literal measurements taken directly from RAW, and a far more trustworthy number. Canon IS behind by about two stops. That is a FACTOR OF FOUR TIMES. DXO would have you believe it was closer to three stops, or EIGHT times...I agree, BS, and highly misleading. That doesn't change the fact that two stops is still a meaningful difference...always has been.
once again, wrong wrong wrong, which is so bizarre because then you flip around and say that photosite density doesn't matter for noise and only sensor size does!!!! that is like saying 1+1=2 and no 1+1 does not equal 2 at the same time.
I think I may begin to see part of our disconnect. Maybe a little clarification of what I think of when I say some of these things would help.
So, first off, I do believe that only sensor size really matters from a fundamental IQ standpoint. I believe that "noise" is relative to sensor size. That's a fairly general statement, maybe I've been lax in my specificity in the past. So, to clarify this first point...I believe that photon shot noise is relative to sensor size. Very specifically, I believe that the total amount of photon shot noise, which affects the signal top to bottom, from the highlights to the shadows, which is an intrinsic part of the real image signal itself, is fundamentally relative to total sensor area.
In that respect, I believe larger sensors will always outperform smaller sensors given similar technology, for identical framing. Assuming non-similar technology, I believe that it is possible, for a short period of time, for a sensor of smaller area to outperform a sensor of larger area...but only so long as the larger sensor's technology is inferior. I believe the generational gap between the small and large sensor would need to be fairly large for the smaller sensor to outperform a larger sensor...within a single generation, I honestly do not believe that any smaller sensor would outperform a larger sensor in terms of overall IQ.
I believe this, because if you frame a subject identically in frames of different physical sizes, the larger the frame, the more total light you gather. That's it. I don't really think that needs any further qualification. More light, better IQ. It's better if you don't normalize, it's better if you do normalize. More total light gathered per unit area of subject, better IQ. It's as simple as that.
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Alright, second. Read noise. I consider read noise to be a fairly distinct form of noise, different in nature and impact than photon shot noise. I do NOT believe that read noise has anything to do with pixel size or sensor size. I believe read noise has to do with the technology itself. I believe read noise is a complex form of noise, contributed to from multiple sources, some of them electronic (i.e. high frequency ADC unit), some of them material in nature (i.e. sensor bias noise, once you average out the random noise components, is fixed....as it partly results from the physical material nature of the sensor itself, it's physical wiring layout, etc.) I believe read noise affects overall image quality, but in a strait up comparison of two images from two cameras with identical sensor sizes, read noise in an invisible quantity. It doesn't really matter how much you scale your images, whether you scale them up or down, whether you normalize or not. Before any editing is performed, read noise is an invisible deep shadow factor, it cannot usually be seen by human eyes.
In this respect, two landscape photos of the same scene taken with different full frame cameras are all largely going to look the same. Photon shot noise is going to be the same, it may just be more finely delineated by a sensor with smaller pixels. Normalize them all, without any other edits, and you aren't going to notice much of any difference between the images. The most significant differences are likely to be firmware/setting related...a Daylight white balance setting will probably differ between cameras (one may be slightly warm, another slightly cold), small nuances of exposure may differ between cameras (one may slightly overexpose, another may slightly underexpose), there may be nuanced differences in color rendition that cater to different personal preferences.
When it comes to read noise, to me, that is all about editing latitude. Because it's a deep shadow thing, it doesn't manifest until you start making some significant exposure adjustments. You have to lift shadows at very low ISO by several stops before the differences between a camera with more sensor+ADC DR and a camera with less sensor+ADC DR really start to manifest. Those differences only matter at ISO 100 and 200, they are significantly diminished by ISO 400, and above that the differences between cameras are so negligible as to be nearly meaningless...sensor size/photon shot noise totally dominate the IQ factor.
I do believe that normalization is important to keep the frequency of photon shot noise, which is the primary visible source of noise in images that have not been edited, at the same frequency for comparison purposes. I do believe that normalization will and should show differences between larger and smaller sensors. I do not believe, however, that normalization of a non-pulled image is going to have any impact on how deep the blacks appear to an observer. I believe the only thing that can actually measure the differences in the deep shadows, where read noise exists, are software algorithms. I do believe that having lower read noise means you have better editing latitude when editing a RAW image in a RAW editor, and that for the purposes of editing, lower read noise, which leads to increased dynamic range (primarily by restoring what would have otherwise been lost to read noise in the shadows) is a good thing, and something that can and does certainly improve certain types of photography. This is the fundamental crux of my belief that DXO's PrintDR numbers are very misleading, and why I prefer to refer to their ScreenDR numbers...as the increase in DR that you gain from having lower read noise is only really of value WHEN editing a RAW image and lifting shadows. Otherwise, I really don't care about comparing cameras within a "DXO-specific context"...I care about comparing cameras based on what you can actually literally do with them in real life. (I KNOW you disagree with this one, but we should just agree to disagree here, because neither of us is ever going to win this argument.

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That is my stance on these things. I am pretty sure you'll disagree in one way or another, and that's ok. However I do not believe that my assessment of these things is fundamentally wrong. I believe it may be different than your assessment, or DXO's assessment for that matter. But I do not believe I have a wrong stance on this subject. I separate photon shot noise and the impact it has on overall IQ (which is significantly greater) from read noise, and the impact it has on the editing latitude you might experience when adjusting exposure of a RAW image in a RAW editor at an unscaled, native image size.