E-M5 has DR 13!

Started Apr 13, 2012 | Discussions
Sergey Borachev
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E-M5 has DR 13!
Apr 13, 2012

Can the technical experts who have been bombarding pixels with photon accelerators and dissecting noise particles emitted comment on what the Techradar review's verdict regarding E-M5's stupendous image results?

I would really like to hear from those who have previously analysed to great details RAW files comment about the review finding that it has a DR of 13 , and that it is the best of all compact camera. Is that believable?

Everdog
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jpegs only?
In reply to Sergey Borachev, Apr 13, 2012

I thought they evaluated jpegs only.

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bg2b
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hard to get 13 bits of DR from 12-bit RAW files [n/t]
In reply to Sergey Borachev, Apr 13, 2012

nothing to see here

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Detail Man
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E-M5 has DR 13 ! - Only 25.81 Times Higher Than Physically Possible !
In reply to Sergey Borachev, Apr 14, 2012

Sergey Borachev wrote:

Can the technical experts who have been bombarding pixels with photon accelerators and dissecting noise particles emitted comment on what the Techradar review's verdict regarding E-M5's stupendous image results?

I would really like to hear from those who have previously analysed to great details RAW files comment about the review finding that it has a DR of 13 , and that it is the best of all compact camera. Is that believable?

TIFF images (after conversion from raw) from the OMD have a better signal to noise ratio than those from the Fujifilm X Pro 1, Panasonic GX1, Sony NEX-7 and Olympus E-P3, showing that the camera copes well with noise .

Regarding: http://cdn1.mos.techradar.com//art/cameras/LabCharts/Olympus/Olympus_EM5_TIFF_SNR-580-100.JPG

Note that the same (it appears un-named) RAW converter show a Signal/Noise Ratio of around 41.0 dB. A linear ratio of 112.20. Take the logarithm to the base 2 and you get 6.81 EV ("stops").

Measured Dynamic Range cannot in any case exceed 3 dB (41.4%) greater than the measured Signal/Noise Ratio - which the same web-page reports as being 6.81 EV ... 13 EV would be 36.50 times greater. Kind of makes one wonder what is going on "upstairs" in their voluminous heads ...

TIFF images (after conversion from raw) have a high dynamic range across the sensitivity range, with the OM-D achieving the highest result we've seen for any compact system camera .

Regarding: http://cdn1.mos.techradar.com//art/cameras/LabCharts/Olympus/Olympus_EM5_TIFF_DR-580-100.JPG

I have yet to discover the "Higgs Boson", but it seems that you may well have discovered some real "Techno Bozos". But, since they are whispering "sweet nothings" into the ear ... go for it !

Note: Just remember that 12-bit analog/digital converters have less than 12 EV Dynamic Range ...

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dkojevnikov
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Re: E-M5 has DR 13!
In reply to Sergey Borachev, Apr 14, 2012

Sergey Borachev wrote:

Can the technical experts who have been bombarding pixels with photon accelerators and dissecting noise particles emitted comment on what the Techradar review's verdict regarding E-M5's stupendous image results?

I would really like to hear from those who have previously analysed to great details RAW files comment about the review finding that it has a DR of 13 , and that it is the best of all compact camera. Is that believable?

They measured 11 for Nikon V1 and 10 for Nikon J1 where as they have identical sensors and electronics. The error is 1 stop (2 times) so I would wait for other independent tests.

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Sergey Borachev
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Re: E-M5 has DR 13 ! - Only 25.81 Times Higher Than Physically Possible !
In reply to Detail Man, Apr 14, 2012

Thanks, DetailMan, Not! Gee, that is fast, shooting that down.

Yes, I remember something about the 14 bit DAC being responsible for the extra high DR in D7000 and K-5. So, no miracles?

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Macx
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Re: E-M5 has DR 13 ! - Only 25.81 Times Higher Than Physically Possible !
In reply to Detail Man, Apr 14, 2012

Detail Man wrote:

Note: Just remember that 12-bit analog/digital converters have less than 12 EV Dynamic Range ...

I'm just wondering, but could some of the idiosyncrasies you've noted indicate that the sensor may use, for example, 14-bit ADC's and the data is being converted into a 12-bit RAW file format?

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Lights
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Re: E-M5 has DR 13 ! - Only 25.81 Times Higher Than Physically Possible !
In reply to Detail Man, Apr 14, 2012

If the ADC is 12bit I don't understand how they can come to 13 stops conclusion

http://www.cambridgeincolour.com/tutorials/dynamic-range.htm

I've seen some tests from 14bit (Canon) and the improvements seemed to me to be very minimal over 12...I can't remember exactly where I saw it on DPR (the Canon forum) and was a while ago. So much in DR is interpreted by the things we see it on too, monitors, paper, i-pads (my laptop) so much relativity.
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Sergey Borachev
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Re: E-M5 has DR 13 ! - Only 25.81 Times Higher Than Physically Possible !
In reply to Macx, Apr 14, 2012

Macx wrote:

Detail Man wrote:

Note: Just remember that 12-bit analog/digital converters have less than 12 EV Dynamic Range ...

I'm just wondering, but could some of the idiosyncrasies you've noted indicate that the sensor may use, for example, 14-bit ADC's and the data is being converted into a 12-bit RAW file format?

I think it is true that the images from this camera are intriguing based on its size and I am hoping it does something similar to what you mentioned or something not conventional to provide extra IQ.

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MichaelKJ
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Re: E-M5 has DR 13!
In reply to Sergey Borachev, Apr 14, 2012

Would love for it to be true. However, this is a site that reviews phones, tablets, computers, TVs, Blu-ray players and cameras.

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micksh6
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Re: hard to get 13 bits of DR from 12-bit RAW files [n/t]
In reply to bg2b, Apr 14, 2012

Hard, but not impossible. It's about raw response curves. DxO rated Sony NEX-7 DR at 13.4 EV. Guess, how many bits per pixel are in Sony RAW file. Hint: No more than in E-M5 raw file.

bg2b wrote:

nothing to see here

Right.

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Detail Man
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Re: E-M5 has DR 13 ! - Only 25.81 Times Higher Than Physically Possible !
In reply to Macx, Apr 14, 2012

Macx wrote:

Detail Man wrote:

Note: Just remember that 12-bit analog/digital converters have less than 12 EV Dynamic Range ...

I'm just wondering, but could some of the idiosyncrasies you've noted indicate that the sensor may use, for example, 14-bit ADC's and the data is being converted into a 12-bit RAW file format?

It sounds like you might want to follow through on my further thoughts on that thread. See:

http://forums.dpreview.com/forums/read.asp?forum=1041&message=41194118
Addendum: http://forums.dpreview.com/forums/read.asp?forum=1041&message=41194176

and:

http://forums.dpreview.com/forums/read.asp?forum=1041&message=41194129

... a realistic and (what should rightly be) humbling epistle for all involved in alleged analysis of DPReview Studio Comparison Tool RAW test-shots; a thorough recitation of the measurement uncertainties involved (which also references my previous related post on the same thread, here):

http://forums.dpreview.com/forums/read.asp?forum=1041&message=41173387

I'm no industry-expert, but my general feel is that it is rather unlikely that the E-M5 employs 14-bit analog/digital conversion. bobn2 would seem to be the best person to ask about that possibility

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Detail Man
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Re: hard to get 13 bits of DR from 12-bit RAW files [n/t]
In reply to micksh6, Apr 14, 2012

micksh6 wrote:

Hard, but not impossible. It's about raw response curves. DxO rated Sony NEX-7 DR at 13.4 EV. Guess, how many bits per pixel are in Sony RAW file. Hint: No more than in E-M5 raw file.

bg2b wrote:

nothing to see here

Right.

Here is an interesting thread started by Iliah Borg a while back with some lively discussions therein involving DSPographer and others which seem to broach what is going on internally in the NEX-7:

http://forums.dpreview.com/forums/readflat.asp?forum=1042&thread=39707815

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SphericalAberration
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Re: hard to get 13 bits of DR from 12-bit RAW files [n/t]
In reply to Detail Man, Apr 14, 2012

Let me have a go at trying to put this straight :
Signal to noise ratio is not the same as dynamic range.

If the sensor full scale corresponds to 13EV of light above dark = 6.02 x 13 dB = 78.26 dB = FS.

Likewise for an ADC the best possible FS SNR = 6.02N + 1.76 dB

For 12 bit it's not possible to have signal to noise ratio SNR better than 74dB.

However notice that the SNR plots from the cameras are way below this number e.g. 42dB.

That is because each ADC bit change corresponds to more than 6dB or 1EV change in light level.

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UnderDriven
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Re: hard to get 13 bits of DR from 12-bit RAW files [n/t]
In reply to bg2b, Apr 14, 2012

DxOMark can indicate higher values than the number of bits in the RAW file if you use the "Print" tab, due to the scaling of the image to 8MP (scaling reduces noise and their DR value is based on the noise floor). If you use the "Screen" tab you should get an absolute reading. For example, when using the "Print" tab the Sony A55 has a DR of 12.39 which exceeds the 12-bit RAW format. However, if you use the "Screen" tab the DR is 11.88. At least that is one possible explanation I can come up with...

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Detail Man
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Clarification about how Digital Camera DR and SNR are specified
In reply to Detail Man, Apr 14, 2012

Detail Man wrote:

Sergey Borachev wrote:

Can the technical experts who have been bombarding pixels with photon accelerators and dissecting noise particles emitted comment on what the Techradar review's verdict regarding E-M5's stupendous image results?

I would really like to hear from those who have previously analysed to great details RAW files comment about the review finding that it has a DR of 13 , and that it is the best of all compact camera. Is that believable?

TIFF images (after conversion from raw) from the OMD have a better signal to noise ratio than those from the Fujifilm X Pro 1, Panasonic GX1, Sony NEX-7 and Olympus E-P3, showing that the camera copes well with noise .

Regarding: http://cdn1.mos.techradar.com//art/cameras/LabCharts/Olympus/Olympus_EM5_TIFF_SNR-580-100.JPG

Note that the same (it appears un-named) RAW converter show a Signal/Noise Ratio of around 41.0 dB. A linear ratio of 112.20. Take the logarithm to the base 2 and you get 6.81 EV ("stops").

Measured Dynamic Range cannot in any case exceed 3 dB (41.4%) greater than the measured Signal/Noise Ratio - which the same web-page reports as being 6.81 EV ... 13 EV would be 36.50 times greater. Kind of makes one wonder what is going on "upstairs" in their voluminous heads ...

TIFF images (after conversion from raw) have a high dynamic range across the sensitivity range, with the OM-D achieving the highest result we've seen for any compact system camera .

Regarding: http://cdn1.mos.techradar.com//art/cameras/LabCharts/Olympus/Olympus_EM5_TIFF_DR-580-100.JPG

I have yet to discover the "Higgs Boson", but it seems that you may well have discovered some real "Techno Bozos". But, since they are whispering "sweet nothings" into the ear ... go for it !

This remains yet to be determined. I will let it stand for now until DxOMark publishes test results ...

Note: Just remember that 12-bit analog/digital converters have less than 12 EV Dynamic Range

(Perhaps) the E-M5 does indeed use a fancy non-linear compression scheme in a manner similar to the Sony NEX-7. Time will tell, and dreamers have more time to entertain sweet dreams. However, (if so), the E-M5 circulating about these days would be compressed (needing the inverse process of digital expansion to result in a process-able RAW image-file) - and that would have been readily apparent to any/all persons who have obtained those image-files. No indication of that to date ...
.

My statements about DR not being able to exceed SNR by more than 3 dB related to the case (as in specifying audio signal processing devices) where the maximum linearly reproduce-able signal-level is divided by the root-mean-square (RMS, vector-summed) value of the "noise-floor" (composed of random as well as periodic noise sources as amplified at the point in the signal-chain of measurment). In those cases of measuring DR and SNR, the peak value of the maximum linearly reproduce-able signal-level is used in the calculation of DR, and the RMS value of the maximum linearly reproduce-able signal-level is used in the calculation of SNR. Since the ratio of the peak to the RMS-average of a sinusoidal test-signal is the square-root of 2 (1.414, or 3 dB when expressed in units of voltage or current), this is why I said what I said (about maximum possible DR related to measured SNR by a difference of 3 dB). I neglected to use my only average brain before posting.

In the case of a digital camera, DR is measured by taking the ratio of the image-sensor system's maximum (so deemed linear, perhaps ambitiously, by somebody ... ;)) output signal when illuminated , divided by the RMS value of the image-sensor system's "noise-floor" when not illuminated - or, in the case of DxOMark, apparently very slightly illuminated to the point where the ratio of the signal corresponding to that slight illumination is equal to the RMS value of the "noise-floor" that exists in that particular situation. Thus, when the Signal/Noise Ratio equals 1.0 (0.0 dB).

In the case of a digital camera, (the maximum) SNR is measured by taking the ratio of the image-sensor system's maximum (so deemed linear, perhaps ambitiously, by somebody ... ;)) output signal when illuminated divided by the RMS (vector-summed) value of the sum of all noise-sources (Read Noise, Dark Noise, Photon Shot Noise, etc.). As a result of the existence (almost entirely) of Photon Shot Noise in that situation, the SNR is indeed smaller in value than the DR (as can be seen in DxOMark's RAW-level test-results). I write this in order to amend my misguiding of the readers ...
.

That being said, I do think that TechRadar's test-results seem perhaps just "a bit" (actually more like "two bits" or so) hard to believe. I don't see any mention of the RAW converter/processor used. That in itself seems rather odd, and lacking in reasonable specificity. Please provide a reference if you yourself have found such information regarding test procedures utilized. Dream on!

DM ...

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Detail Man
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TechRadar used DxOMark's test-gear to analyze TIFFs ?
In reply to Detail Man, Apr 14, 2012

Detail Man wrote:

... I do think that TechRadar's test-results seem perhaps just "a bit" (actually more like "two bits" or so) hard to believe. I don't see any mention of the RAW converter/processor used. That in itself seems rather odd, and lacking in reasonable specificity. Please provide a reference if you yourself have found such information regarding test procedures utilized ...

Hmmm,

http://www.techradar.com/news/photography-video-capture/cameras/noise-and-dynamic-range-results-explained-1027588

Wonder why the RAW processor/converter used to convert to 16-bit TIFF is not similarly disclosed?

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Jogger
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just wait for the real DxOMark tests
In reply to Detail Man, Apr 14, 2012

They are doing something wonky. No way in hall that the EM5 is beating the D4/D800 in DR. Thats just ridiculous. They messed up their "test".

This is what should be expected.

Detail Man wrote:

Detail Man wrote:

... I do think that TechRadar's test-results seem perhaps just "a bit" (actually more like "two bits" or so) hard to believe. I don't see any mention of the RAW converter/processor used. That in itself seems rather odd, and lacking in reasonable specificity. Please provide a reference if you yourself have found such information regarding test procedures utilized ...

Hmmm,

http://www.techradar.com/news/photography-video-capture/cameras/noise-and-dynamic-range-results-explained-1027588

Wonder why the RAW processor/converter used to convert to 16-bit TIFF is not similarly disclosed?

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jkrumm
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Re: E-M5 has DR 13!
In reply to Sergey Borachev, Apr 14, 2012

I would guess they are using Viewer to convert to Tiffs, and Viewer clearly has a strong noise filter now for the EM5, even when you turn it off, so it's not surprising they are clean.

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Louis_Dobson
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Re: E-M5 has DR 13!
In reply to Sergey Borachev, Apr 14, 2012

They're not looking at the RAW itself, so forget it.

I suspect they are analysing a TIFF created by Viewer, and Viewer applies NR even in the "off" position, but either way, not, that's not credible.

Sergey Borachev wrote:

Can the technical experts who have been bombarding pixels with photon accelerators and dissecting noise particles emitted comment on what the Techradar review's verdict regarding E-M5's stupendous image results?

I would really like to hear from those who have previously analysed to great details RAW files comment about the review finding that it has a DR of 13 , and that it is the best of all compact camera. Is that believable?

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