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Comparing JPEG Quality
Use this page to compare the quality of JPEG image compression used in various sources, including both digital SLR / digicams (Canon, Nikon, Sony, etc.) and image editing software (such as Photoshop). Note that this is a comparison on each camera's JPEG output — with RAW output you can bypass the compression quantization "error" step. The data points for Photoshop and IrfanView are useful to determine how the final output quality compares.
This interactive page is very new and will be improved over time. Please leave any feedback or suggestions below. Do you want to see data about a camera that is not listed below? Let me know and I'll add it.
Variable Compression / Quantization
Note that there are a growing number of digicams that use variable quantization tables to produce their JPEG output. As a result, it is possible that a camera may generate photos that use a dozen different quantization tables, meaning that the effective compression quality can, in fact, cover quite a large range. For this reason, I have omitted many of these digital cameras from the list below.
Important note about Quality Factors
It is extremely important that the reader understand that compression quality cannot truly be represented by a single value. JPEG compression quality is actually defined by a pair of quantization tables (each with an array of 64 values). Trying to make a comparison between a pair of matrices is not at all straightforward (or always possible).
So, then why are "quality" numbers listed for each camera/software source? Many programs encode their JPEG images using quantization tables that are generated by scaling the coefficients in a "standard" table that is provided in the ITU-T specification.
The IJG group has proposed a method of scaling these coefficients according to a "quality factor" scale. This is NOT a percentage! It is merely a number from 1-100 representing the scaling factor used in generating the table. A quality factor of 100 does not mean Lossless compression! Instead, it generally represents the quality factor that will generate the highest quality compressed image with the provided scaling algorithm.
That said, many software programs and some digicams are indeed using scaled versions of this standard table. If we know that a given program has used the IJG scaling method, then we can indeed make a comparison, because all numbers in the matrices will move according to the algorithm in a similar manner.
So, what about other digicams / software editors that didn't use the IJG scaling method? People always love to make comparisons, and comparing multiple 64-element matrices is not intuitive to the average person. Therefore, as an incredibly rough approximation, a calculation has been made for each source to derive the closest / approximate IJG quality factor for a given table. If the quantization tables follow the standard trend of limited compression in the low-frequency components rising to moderate compression in the high-frequency components, then the approximate quality factor may indeed give one an idea as to how the overall quality may appear.
How to Compare Matrices
When you use the comparison tool below, an assessment is done between the sets of 64 coefficients that make up a quantization table. In order to come up with a better than / worse than assessment, the tables are simplified into high frequency coefficients and low frequency coefficients. If the high frequency coefficients in table A are nearly always greater than the high frequency components in table B, then we can indeed state that digicam A's high frequency content will be compressed more poorly than digicam B. In cases where there is not enough of a clear difference, the comparison will report this accordingly.
JPEG Comparison List of all Cameras & Sources
The following is a sorted summary of the JPEG Quality factor comparisons between all cameras and other sources including Adobe Photoshop and IrfanView. The list is ordered by the approximate luminance quality factor (please see above!). This is only a very rough comparison as the quality factor is not necessarily a good comparison as it doesn't discern between low and high frequency component differences in the same way that the Human Visual System does. Thus, it is only a starting point -- consult the quantization tables themselves for a more accurate comparison. It also provides a loose guide as to the quality settings in Photoshop Save As when coming from various digicams.
The other very important point is the chroma subsampling being used in the chrominance channel. Note that a camera with a subsampling of 1x1 (i.e. none) and lower chrominance quality factor may appear better than an image compressed with a subsampling factor of 2x1 and a higher chrominance quality factor. Note such a changeover in the Photoshop quality factors, where the subsampling is automatically chosen depending on the quality level.
Lastly, sources with the same quantization tables have been grouped together, as they should all have equivalent JPEG compression quality. Of course the following does not take into account any of the differences in optics quality, CMOS/CCD sensor resolution or quality derived from a RAW->JPEG workflow..
NOTE: The following is not an accurate comparison of quality (as it is just listing the approximate quality factor, which only truly applies if the IJG tables were used). Direct quantization table comparisons (using the drop boxes above) will provide a more accurate comparison. The list below can only be used as a rough ballpark comparison chart in light of the limitations of "approximate quality factor" described earlier.
Make | Model | Quality Mode | Chroma Subsamp | Quality Factor Lum | Quality Factor Chr |
---|---|---|---|---|---|
PENTAX | PENTAX Optio S5i | 2x2 | 100 | 100 | |
IrfanView | 100 | 1x1 | 100 | 100 | |
MS Office | MS Office Picture Manager | 2x1 | 100 | 100 | |
CASIO COMPUTER CO.,LTD. | EX-S500 | fine | 2x2 | 100 | 100 |
KONICA MINOLTA | MAXXUM 5D | 2x1 | 98.4798 | 99.1842 | |
KONICA MINOLTA | MAXXUM 7D | 2x1 | 98.4798 | 99.1842 | |
SONY | DSLR-A700 | 2x1 | 98.4798 | 99.1842 | |
Canon | Canon EOS-1Ds Mark II | fine | 2x1 | 98.3246 | 98.829 |
NIKON | E8800 | EXTRA | 2x1 | 98.3246 | 98.829 |
NIKON | NIKON D2X | FINE | 2x1 | 98.3246 | 98.829 |
SIGMA | SIGMA SD10 | Qual:12 | 1x1 | 98.3246 | 98.829 |
SIGMA | SIGMA SD10 | Qual:12 | 1x1 | 98.3246 | 98.829 |
SIGMA | SIGMA SD9 | 1x1 | 98.3246 | 98.829 | |
OLYMPUS IMAGING CORP. | FE240/X795 | shq | 2x1 | 98.3246 | 98.829 |
NIKON | NIKON D3 | FINE | 2x1 | 98.3246 | 98.829 |
FUJIFILM | FinePix S9500 | fine | 2x1 | 98.2922 | 99.0936 |
OLYMPUS CORPORATION | E-1 | 2x1 | 98.2909 | 98.8054 | |
Canon | Canon EOS-1D Mark II | fine | 2x1 | 98.2543 | 98.7342 |
Photoshop | Save For Web 100 | 1x1 | 98.249 | 98.3854 | |
Photoshop | Save As 12 | 1x1 | 98.1053 | 98.3557 | |
OLYMPUS OPTICAL CO.,LTD | E-20,E-20N,E-20P | SHQ | 2x1 | 98.049 | 98.4029 |
FUJIFILM | FinePix S9000 | FINE | 2x1 | 98.0243 | 98.2769 |
NIKON | NIKON D50 | FINE | 2x1 | 98.0237 | 98.389 |
NIKON | NIKON D70s | FINE | 2x1 | 98.0237 | 98.389 |
NIKON | NIKON D80 | FINE | 2x1 | 98.0237 | 98.389 |
NIKON | NIKON D300 | FINE | 2x1 | 98.0237 | 98.389 |
SONY | DSC-F88 | 2x1 | 97.9621 | 98.389 | |
SONY | DSC-F828 | 2x1 | 97.9621 | 98.389 | |
NIKON | NIKON D200 | FINE | 2x1 | 97.9128 | 98.389 |
FUJIFILM | FinePix E550 | fine | 2x1 | 97.8608 | 98.265 |
OLYMPUS IMAGING CORP. | E-410 | SHQ | 2x1 | 97.8325 | 98.3557 |
NIKON | NIKON D1H | FINE | 2x1 | 97.8288 | 98.3557 |
NIKON | NIKON D2H | FINE | 2x1 | 97.8288 | 98.3557 |
NIKON | NIKON D100 | FINE | 2x1 | 97.8288 | 98.3557 |
NIKON | NIKON D80 | FINE | 2x1 | 97.8288 | 98.3557 |
Canon | Canon PowerShot G1 | superfine | 2x1 | 97.7914 | 97.4087 |
NIKON | COOLPIX P2 | FINE | 2x1 | 97.6816 | 97.9296 |
PENTAX | PENTAX Optio 750Z | 2x1 | 97.6816 | 97.9296 | |
SONY | DSC-H1 | variable | 2x1 | 97.6816 | 97.9296 |
SONY | DSC-H9 | variable | 2x1 | 97.6816 | 97.9296 |
SONY | DSC-H2 | variable | 2x1 | 97.6816 | 97.9296 |
SONY | DSC-H5 | variable | 2x1 | 97.6816 | 97.9296 |
SONY | DSC-H7 | variable | 2x1 | 97.6816 | 97.9296 |
SONY | DSC-P200 | 2x1 | 97.6816 | 97.9296 | |
FUJIFILM | FinePix S3Pro | fine | 2x1 | 97.617 | 97.8154 |
OLYMPUS IMAGING CORP. | E-330 | 2x1 | 97.5346 | 97.9296 | |
OLYMPUS CORPORATION | u30D,S410D,u410D | variable | 2x1 | 97.5346 | 97.9296 |
FUJIFILM | FinePix S20Pro | fine | 2x1 | 97.4992 | 97.8035 |
FUJIFILM | FinePixS2Pro | fine | 2x1 | 97.4626 | 97.8035 |
Canon | Canon EOS 5D | fine | 2x1 | 97.2933 | 97.5132 |
Canon | Canon EOS 40D | fine | 2x1 | 97.2933 | 97.5132 |
Canon | Canon EOS-1D Mark II N | fine | 2x1 | 97.2933 | 97.5132 |
Canon | Canon EOS-1D Mark III | fine | 2x1 | 97.2933 | 97.5132 |
Canon | Canon EOS 10D | fine | 2x1 | 97.2894 | 97.5132 |
Canon | Canon EOS 20D | fine | 2x1 | 97.2894 | 97.5132 |
Canon | Canon EOS 30D | fine | 2x1 | 97.2894 | 97.5132 |
Canon | Canon EOS 300D DIGITAL | fine | 2x1 | 97.2894 | 97.5132 |
Canon | Canon EOS DIGITAL REBEL XT | fine | 2x1 | 97.2894 | 97.5132 |
Canon | Canon EOS 350D DIGITAL | fine | 2x1 | 97.2894 | 97.5132 |
Canon | Canon EOS DIGITAL REBEL XTi | fine | 2x1 | 97.2894 | 97.5132 |
Canon | Canon EOS D60 | fine | 2x1 | 97.2894 | 97.5132 |
Canon | Canon EOS 300D DIGITAL | 2x1 | 97.2894 | 97.5132 | |
Canon | Canon PowerShot A40 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot A70 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot A430 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot A700 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot S3 IS | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot S40 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot S45 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot S50 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot S60 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot S70 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot S80 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon DIGITAL IXUS 800 IS | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon DIGITAL IXUS 850 IS | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon DIGITAL IXUS 900Ti | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot SD1000 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot G3 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot G5 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot A510 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot A520 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot TX1 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon DIGITAL IXUS 55 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon DIGITAL IXUS 40 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot S5 IS | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot SD40 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot SD600 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot SD800 IS | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot SD20 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon PowerShot G6 | superfine | 2x1 | 97.2395 | 95.1671 |
Canon | Canon EOS D30 | fine | 2x1 | 97.2194 | 97.5132 |
PENTAX | PENTAX *ist D | 2x1 | 97.1826 | 97.5132 | |
PENTAX | PENTAX *ist DS | 2x1 | 97.1826 | 97.5132 | |
PENTAX | PENTAX *ist DL | 2x1 | 97.1826 | 97.5132 | |
PENTAX | PENTAX *ist DS2 | 2x1 | 97.1826 | 97.5132 | |
PENTAX | PENTAX K100D | 2x1 | 97.1826 | 97.5132 | |
SAMSUNG TECHWIN | GX-1L | 2x1 | 97.1826 | 97.5132 | |
Canon | Canon PowerShot Pro1 | 2x1 | 97.1671 | 95.1671 | |
Canon | Canon DIGITAL IXUS II | 2x1 | 97.1671 | 95.1671 | |
OLYMPUS IMAGING CORP. | E-300 | 2x1 | 97.1496 | 97.3547 | |
OLYMPUS CORPORATION | u30D,S410D,u410D | variable | 2x1 | 97.1496 | 97.3547 |
Samsung Techwin | superfine | 2x1 | 97.1343 | 97.087 | |
FUJIFILM | MX-500 | fine | 2x1 | 97.044 | 97.3753 |
FUJIFILM | FinePix A700 | fine | 2x1 | 97.0043 | 96.961 |
OLYMPUS CORPORATION | u30D,S410D,u410D | variable | 2x1 | 96.9998 | 97.331 |
NIKON | NIKON D1X | FINE | 2x1 | 96.9693 | 96.9937 |
NIKON | NIKON D70 | FINE | 2x1 | 96.9693 | 96.9937 |
FUJIFILM | FinePix E900 | fine | 2x1 | 96.9466 | 96.961 |
SONY | DSC-N2 | fine | 2x1 | 96.9452 | 96.9937 |
SONY | DSC-H1 | variable | 2x1 | 96.9452 | 96.9937 |
SONY | DSC-H9 | variable | 2x1 | 96.9452 | 96.9937 |
SONY | DSC-W35 | fine | 2x1 | 96.9452 | 96.9937 |
SONY | DSC-H2 | variable | 2x1 | 96.9452 | 96.9937 |
SONY | DSC-H7 | variable | 2x1 | 96.9452 | 96.9937 |
SONY | DSC-H5 | variable | 2x1 | 96.9452 | 96.9937 |
FUJIFILM | FinePixS1Pro | fine | 2x1 | 96.9384 | 96.961 |
Canon | Canon PowerShot S1 IS | superfine | 2x1 | 96.8375 | 94.4437 |
Photoshop | Save For Web 090 | 1x1 | 96.7543 | 95.938 | |
PENTAX | PENTAX Optio M40 | 2x1 | 96.722 | 96.9146 | |
FUJIFILM | MX-500 | normal | 2x1 | 96.714 | 96.9159 |
OLYMPUS IMAGING CORP. | E-500 | 2x1 | 96.5989 | 96.8774 | |
OLYMPUS IMAGING CORP. | uD800,S800 | SHQ | 2x1 | 96.5989 | 96.8774 |
OLYMPUS CORPORATION | u30D,S410D,u410D | variable | 2x1 | 96.5989 | 96.8774 |
Canon | Canon EOS-1DS | fine | 2x1 | 96.5918 | 96.5122 |
Canon | Canon EOS-1D | fine | 2x1 | 96.5918 | 96.5122 |
OLYMPUS CORPORATION | u30D,S410D,u410D | variable | 2x1 | 96.4426 | 96.7906 |
NIKON | NIKON D1 | FINE | 2x1 | 96.151 | 96.0156 |
SIGMA | SIGMA SD9 | 2x2 | 96.0636 | 96.0156 | |
NIKON | E8400 | FINE | 2x1 | 96.0636 | 96.0156 |
SONY | DSC-H1 | variable | 2x1 | 96.0636 | 96.0156 |
SONY | DSC-H9 | variable | 2x1 | 96.0636 | 96.0156 |
SONY | DSC-H2 | variable | 2x1 | 96.0636 | 96.0156 |
SONY | DSC-H5 | variable | 2x1 | 96.0636 | 96.0156 |
OLYMPUS IMAGING CORP. | uD800,S800 | variable | 2x1 | 95.569 | 95.8689 |
Photoshop | Save As 11 | 1x1 | 95.479 | 95.4894 | |
SONY | DSLR-A100 | 2x1 | 95.2971 | 94.0658 | |
SONY | DSLR-A700 | fine | 2x1 | 95.2971 | 94.0658 |
NIKON | COOLPIX P3 | FINE | 2x1 | 95.2112 | 95.1022 |
Sony Ericsson | K800i | variable | 2x1 | 95.1419 | 94.9469 |
PENTAX | PENTAX K10D | 2x1 | 95.0371 | 94.9093 | |
NIKON | E8700 | FINE | 2x1 | 95.0371 | 94.9093 |
SONY | DSC-N1 | fine | 2x1 | 95.0371 | 94.9093 |
SONY | DSC-H1 | variable | 2x1 | 95.0371 | 94.9093 |
SONY | DSC-H9 | variable | 2x1 | 95.0371 | 94.9093 |
SONY | DSC-H2 | variable | 2x1 | 95.0371 | 94.9093 |
SONY | DSC-H5 | variable | 2x1 | 95.0371 | 94.9093 |
SONY | DSC-H7 | variable | 2x1 | 95.0371 | 94.9093 |
SONY | DSC-H7 | variable | 2x1 | 95.0371 | 94.9093 |
PENTAX | PENTAX Optio A10 | 2x1 | 94.8469 | 96.3367 | |
NIKON | COOLPIX P4 | 2x1 | 94.7811 | 94.5068 | |
FUJIFILM | FinePix F810 | normal | 2x1 | 94.5757 | 94.0125 |
KONICA MINOLTA | DiMAGE X1 | fine | 2x1 | 94.3699 | 94.0972 |
NIKON | COOLPIX P4 | FINE | 2x1 | 94.1892 | 93.9684 |
FUJIFILM | FinePix S7000 | fine | 2x1 | 94.147 | 93.8883 |
Photoshop | Save For Web 080 | 1x1 | 94.1269 | 93.0311 | |
FUJIFILM | FinePix S5000 | normal | 2x1 | 94.1221 | 93.8883 |
NIKON | COOLPIX L12 | FINE | 2x1 | 94.0161 | 93.9312 |
SONY | DSC-H9 | variable | 2x1 | 94.0161 | 93.9312 |
SONY | DSC-H5 | variable | 2x1 | 94.0161 | 93.9312 |
NIKON | COOLPIX P5000 | FINE | 2x1 | 94.0161 | 93.9312 |
OLYMPUS IMAGING CORP. | uD800,S800 | variable | 2x1 | 93.6175 | 93.8444 |
OLYMPUS IMAGING CORP. | u700,S700 | 2x1 | 93.6175 | 93.8444 | |
OLYMPUS IMAGING CORP. | E-410 | 2x1 | 93.6049 | 93.8444 | |
Canon | Canon PowerShot A640 | fine | 2x1 | 92.9605 | 88.2376 |
Canon | Canon PowerShot G6 | fine | 2x1 | 92.9605 | 88.2376 |
Canon | Canon PowerShot S2 IS | fine | 2x1 | 92.9605 | 88.2376 |
Canon | Canon PowerShot SD400 | fine | 2x1 | 92.9605 | 88.2376 |
Canon | Canon PowerShot A520 | fine | 2x1 | 92.9605 | 88.2376 |
Canon | Canon DIGITAL IXUS 700 | fine | 2x1 | 92.9605 | 88.2376 |
Canon | Canon PowerShot A630 | fine | 2x1 | 92.9605 | 88.2376 |
Canon | Canon PowerShot S30 | fine | 2x1 | 92.9605 | 88.2376 |
Canon | Canon PowerShot SD700 IS | fine | 2x1 | 92.9605 | 88.2376 |
Canon | Canon DIGITAL IXUS 60 | fine | 2x1 | 92.9605 | 88.2376 |
Canon | Canon PowerShot G1 | fine | 2x1 | 92.9605 | 83.5027 |
NIKON | E995 | FINE | 2x1 | 92.9576 | 92.9085 |
NIKON | E4600 | FINE | 2x1 | 92.9576 | 92.9085 |
SONY | DSC-W70 | 2x1 | 92.9576 | 92.9085 | |
OLYMPUS IMAGING CORP. | u1000/S1000 | SHQ | 2x1 | 92.9576 | 92.9085 |
SONY | DSC-H1 | variable | 2x1 | 92.9576 | 92.9085 |
SONY | DSC-H9 | variable | 2x1 | 92.9576 | 92.9085 |
SONY | DSC-H5 | variable | 2x1 | 92.9576 | 92.9085 |
SONY | DSC-H2 | variable | 2x1 | 92.9576 | 92.9085 |
PENTAX | PENTAX Optio A30 | 2x1 | 92.7615 | 95.4061 | |
OLYMPUS IMAGING CORP. | u700,S700 | variable | 2x1 | 92.4518 | 92.7738 |
OLYMPUS IMAGING CORP. | uD800,S800 | variable | 2x1 | 92.2911 | 92.7738 |
OLYMPUS IMAGING CORP. | u700,S700 | variable | 2x1 | 92.2911 | 92.7738 |
SONY | DSC-H9 | variable | 2x1 | 91.8608 | 91.898 |
NIKON | COOLPIX S10 | FINE | 2x1 | 91.8608 | 91.898 |
Photoshop | Save As 10 | 1x1 | 91.6431 | 92.5731 | |
SONY | DSC-T100 | 2x1 | 90.9622 | 90.9581 | |
PENTAX | PENTAX Optio S | 2x2 | 90.9259 | 90.9347 | |
OLYMPUS IMAGING CORP. | u700,S700 | variable | 2x1 | 90.7727 | 91.2087 |
FUJIFILM | FinePix S5000 | normal | 2x1 | 90.5629 | 90.5001 |
Samsung Electronics | Anycall SPH-B4100 | 2x1 | 90.5442 | 90.4434 | |
Photoshop | Save For Web 070 | 1x1 | 90.4171 | 88.9253 | |
Canon | Canon EOS 10D | norm | 2x1 | 90.099 | 90.4197 |
SONY | DSC-H9 | variable | 2x1 | 90.0596 | 89.9304 |
Sony Ericsson | K800i | variable | 2x1 | 90.0596 | 89.9304 |
IrfanView | 090 | 2x2 | 90.0596 | 89.9304 | |
SONY | DSC-R1 | fine | 2x1 | 90.0596 | 89.9304 |
SONY | DSC-W1 | 2x1 | 90.0596 | 89.9304 | |
OLYMPUS IMAGING CORP. | u700,S700 | variable | 2x1 | 90.024 | 90.2869 |
OLYMPUS IMAGING CORP. | uD800,S800 | variable | 2x1 | 89.1122 | 89.3138 |
NIKON | NIKON D40 | FINE | 2x1 | 88.3666 | 88.3729 |
Sony Ericsson | K800i | variable | 2x1 | 88.0672 | 87.9468 |
SONY | DSC-H9 | variable | 2x1 | 88.0479 | 87.9468 |
Photoshop | Save As 09 | 1x1 | 88.0366 | 90.9342 | |
Apple | iPhone | 2x2 | 87.9688 | 87.9329 | |
OLYMPUS IMAGING CORP. | uD800,S800 | variable | 2x1 | 87.7613 | 88.2625 |
FUJIFILM | FinePix F700 | normal | 2x1 | 87.4631 | 87.1065 |
Photoshop | Save For Web 060 | 1x1 | 85.5878 | 82.8867 | |
Photoshop | Save As 08 | 1x1 | 83.8787 | 89.1117 | |
FUJIFILM | FinePix S5000 | normal | 2x1 | 82.7197 | 82.5478 |
Photoshop | Save For Web 051 | 1x1 | 82.5162 | 79.0152 | |
Sony Ericsson | K800i | variable | 2x1 | 82.0076 | 81.878 |
Photoshop | Save For Web 050 | 2x2 | 81.5881 | 86.9581 | |
SONY | DSC-H9 | variable | 2x1 | 81.088 | 80.8553 |
Photoshop | Save As 06 | 2x2 | 80.7187 | 90.6277 | |
IrfanView | 080 | 2x2 | 79.9379 | 79.8685 | |
FUJIFILM | FinePix F40fd | 2x2 | 79.9379 | 79.8685 | |
Photoshop | Save As 07 | 1x1 | 77.3938 | 87.1517 | |
SONY | DSC-H9 | variable | 2x1 | 75.8359 | 75.7596 |
Photoshop | Save As 05 | 2x2 | 74.8237 | 88.8975 | |
MS Paint | MS Paint | 2x2 | 74.7469 | 74.7406 | |
Photoshop | Save For Web 040 | 2x2 | 72.901 | 80.8121 | |
Canon | Canon PowerShot S30 | video | 2x1 | 72.2102 | 69.9584 |
Photoshop | Save As 04 | 2x2 | 70.4571 | 87.3217 | |
IrfanView | 070 | 2x2 | 70.0621 | 70.1315 | |
Photoshop | Save As 03 | 2x2 | 65.8554 | 85.9507 | |
Photoshop | Save For Web 030 | 2x2 | 65.6783 | 76.0281 | |
Photoshop | Save As 02 | 2x2 | 62.4967 | 85.1483 | |
IrfanView | 060 | 2x2 | 59.9404 | 60.0696 | |
Photoshop | Save For Web 020 | 2x2 | 58.4501 | 71.3408 | |
Photoshop | Save As 01 | 2x2 | 51.5026 | 81.9067 | |
IrfanView | 050 | 1x1 | 50 | 50 | |
JPEG Standard | 2x1 | 50 | 50 | ||
Photoshop | Save As 00 | 2x2 | 46.0214 | 80.8089 | |
Photoshop | Save For Web 010 | 2x2 | 40.2033 | 63.3071 | |
IrfanView | 040 | 2x2 | 39.8625 | 39.8893 |
Reader's Comments:
Please leave your comments or suggestions below!JPEGsnoop's "approximate quality factor" is based upon trying to determine the IJG quality factor, as it appears in cjpeg. If the DQT is truly based upon a scaling of the reference / sample tables that appear in the standard annex, then it should be an accurate representation of it. However, when the DQT values were not based upon a scaling of the annex tables, then there isn't any correct quality factor value. This is why the variance value is shown, which hints at whether the scaling was consistent across all values in the matrix or not. Resolving a sequence of 64 values into a single quality value can be done in a multitude of ways.
Basing on the proposed IJG quality formula, the reverse determination is based on an assumption that all values are scaled consistently which means that one can sum up all matrix entries. Once summed and a mean computed, if the mean value is <100 then:
qual = (200.0 - mean) / 2.0
otherwise
qual = 5000.0 / mean
I discovered your application (Thanks for it!) recently and experimented a bit with various jpeg files. I was curious to know what JPEG chroma sub-sampling rates are used in digital cameras and in the photo processing applications that I use. As I expected jpeg files from Nikon D70s and D3100 were displayed as using 2x1 jpeg chroma sub-sampling. What came as a surprise though was the fact that JPEGsnoop indicated that the highest quality jpegs generated from Nikon RAW (NEF) files using Nikon ViewNX2 application and CaptureNX2 application are using 2x2 jpeg chroma sub-sampling.
How this can be explained? Are Nikon software indeed discarding that much of color information from jpeg images by using 2x2 chroma subsampling, or something is recorded in/extracted from ViewNX2/CaptureNX2 generated jpeg's incorrectly?
After looking on the Internet I found claims that CaptureNX2 uses 1x1 chroma sub-sampling in its highest quality jpegs.
Please see the following link for this:
http://www.dpreview.com/forums/thread/3163509
However JPEGsnoop and Jeffrey's EXIF viewer both indicate that 2x2 jpeg chroma sub-sampling is used.
I am confused about this. It would be really interesting to know what is going on with the jpeg files generated by Nikon RAW processing software.
The software versions used were as follows:
ViewNX2 v.2.1.2
CNX2 v.2.4.5 (trial version).
I have tried "NIKON D50" and its quality mode is fine. I get several different quantization tables. So, I think "NIKON D50" uses variable quantization tables .
However,In you blog, it seems that it has just one table.
Can you explain the difference for me?
Thank you
Thank you for your help.
i know this is an oddballl question, but i design cameras and have a micron 1.3MP sensor feeding a jpeg compressor IC, and the IC tells me things are fine. it outputs a standard JFIF header and then outputs a quadword of bytes with a byte count to the end of the image. i get my 0xFFD8 and count the appropriate byte count looking for the 0xFFD9, which never shows up, nor is in any previous byte, nor is it following. i am not sure what could produce this type of behaviour except possibly that the BT656 front end is counting bytes per line and then a number of lines, but never sees the VSYNC so just keeps going. i know the reason is highly dependant on the unknown internals of the IC, but i was wondering what your thoughts or insights might be on this. FYI, things work fine on an eval board, and there is some noise on my traces because i have 2 boards wired together on the 656 interface. i have color bars, and the byte count reported is very high (40K) vs. 11.5K on the working eval board. in all probability, the noise is being DCT'd as a ton of pixel variance. i also have seen tv encoders work with this amount of noise on the 656 interface before, and they do ok - noise on the monitor, but SOI and EOI are o.k.
thanks
dave bassett
you have given more than one quality factor for same camera name and model what is its mean if we want to create a quantization table with the help of quality factor for that which factor we will use for clearity of image.For sony K800i you gave quality factor 95.14 for lum which do not give clear image and snoop gives 96.15 which give clear image. I am using standered quantization table to create the any quantization table with the help of quality factor.
thanks & regards,
roopa saini
I'm trying to get the jpg quality based on this code: http://www.hackerfactor.com/src/jpegquality.c
The results look good for high quality images but low quality I get obvious wrong results like something negative or otherwise unrealistic compared to the results of your tool. So I'm asking how you get the jpg quality, could you please point me to the right direction or give me a hint?
Best regards,
Kevin
i used below 60% quantization table and got the image
Q-table for 60%
13 9 8 13 19 32 41 49
10 10 11 15 21 46 48 44
11 10 13 19 32 46 55 45
11 14 18 23 41 70 64 50
14 18 30 45 54 87 82 62
19 28 44 51 65 83 90 74
39 51 62 70 82 97 96 81
58 74 76 78 90 80 82 79
But when i use photoshop then the 60% compression factor result using photoshop looks significantly better than the result which i get while using the above mentioned Q table . Any reason for this ?
I am on the way of buying a new digi cam - Canon Digital IXUS 990 IS or similar. I am now wondering that they only support FINE as quality setting which results in
whereas I currently use a casio EX-S880
with this tables
Is it worth to switch from 8 MPixel to 12MPixel with that bad quality settings?
Thanks for your advice.
Please suggest me some accurate quantization tables to get 90% Y & 90% chrm.
Just as a small test I converted a 24bit BMP file into JPEG with both FastStone (FS) and IrfanView (IV) at 90 and 100% quality settings. On-screen, the two FS files are almost indiscernable from the original BMP, but the two IV files appear to be 'brighter'.
Also the file sizes are very different:
90% FS 300kB IV 400kB
100% FS 750kB IV 1800kB
I'm keen to know the process or formula of calculating the Quality level based on the quantization table. I understand (based on JPEGSnoop documentation) that it is based on comparing the quantization table to a known table from the JPEG standard but eagerly looking for more information.
Thanks
Jonathan
Digital Image Ballistics (PDF)
They note getting samples from dpreview
As for sourcing images from dpreview or other websites, it became apparent quite quickly that a significant number of images on these review sites (and manufacturer's sites) have been edited, even though one would have expected them to be original images!
I ran into this early on in compiling the list of compression tables that I've posted online. As a result, I generally decided to omit quality values from cameras that appear to use such a variable scheme. One plan I had was to later augment the list to show the upper and lower bound of these compression quality ranges. Some digicams exhibit huge ranges in compression quality -- enough so that it can become an issue.
Interestingly enough, a file-size priority is generally a poor choice if overall image quality is a concern. Images with finely detailed content (at low ISO/noise) will not be as "compressible" as low-detail images. Therefore, these should result in larger file sizes. Conversely, a bland, flat image will compress easily, allowing for much small file sizes with the same quantization table.
Unfortunately, restricting all JPEG image output to a target file size will generally go against the goal of preserving image quality. For detailed images, you are artificially reducing the compression quality, making JPEG artifacts visible. For low-detail images, you unnecessarily increase file size with little gain in image quality. This is why I'm not particularly keen on the idea of file size priority for general shooting, unless you are trying to keep image sizes to some maximum for some reason (email, etc.)
The other approach, optimal quality priority, does seem to serve a reasonably good purpose, as it should shift the compression quality higher if it detects that the image content necessitates it. My guess is that it works the other way around: starts with the highest compression quality allowed (e.g "fine" level), and if the image content appears to be not particularly complex, it reduces the compression quality (increasing the DQT coefficients) until a compromise is reached.
In developing JPEGsnoop, I have seen thousands of user-submitted compression signatures. From these, I have been able to quickly identify the types of cameras that are using such variable compression scheme (certainly common among Fuji digicams) and the ranges selected for each model.
What I find interesting is how the camera makes the decision about what scaling factor to use to produce the alternate compression tables, and whether the user has any choice in this selection process.
I'll have to play with the menus to see if I can find the setting in question and then I'll re-submit.
Cheers,
Brian
PS - Yeah, it is kind of scandalous that their images were touched in photoshop.
Ok here's the complete table for the 3 settings (now that I found them!) ===normal===
... snipped ...
approx quality factor = 72.21
approx quality factor = 69.96
===fine===
... snipped ...
approx quality factor = 92.96
Approx quality factor = 88.24
===superfine===
.. snipped ...
Approx quality factor = 97.24
Approx quality factor = 95.17
Canon SD800 IS uses this table:
luminance:
chrominance:
Interestingly enough, when I was searching for examples photos from the Canon SD800 IS, I had a look at Canon's official sample gallery for this camera. What really surprised me is that Canon's provided sample photos have actually been edited in Photoshop! Of all sources, this is one that I would have expected to provide the original, unmodified photos. Perhaps they used Photoshop simply to resize the images (and sharpen?), but I think this is pretty misleading.
If possible i would like to ask ... is there any know equation between the quality factor and compression ratio
(For example if quality factor = 50 >> you have 2:1 compression ratio)
In other words how mach reduction the quality factor introduce to the image
without considering the entropy coding...:)
Thanks a lot!
omer
In JPEG, you would generally have to perform an iterative process of multiple compression attempts to come up with a given file size or compression rate.
Thanks
I don't have any experience in trying to send upsampled JPEGs to an online printer, and so others might have better suggestions for you on this front. Good luck!