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by Roger N. Clark
This page shows an analysis of noise, dynamic range, and full well capacity of a Canon 5D Mark II camera.
Procedures for performing this analysis are described in: Procedures for Evaluating Digital Camera Noise, Dynamic Range, and Full Well Capacities; Canon 1D Mark II Analysis
The lowest possible noise from a system detecting light is the noise due to Poisson statistics from the random rate of the arrival of photons. This is called photon statistics, or photon noise. Noise from the electronics will add to the photon noise. Noise in Canon 5D Mark II images is limited by photon statistics at high signal levels and by electronic noise from reading the sensor (called readout noise) and noise from the downstream electronics at very low signal levels. In the case of high signal levels, a system that is photon statistics limited enables us to directly measure how many photons the sensor captures, and by increasing the exposure, we can determine how many photons are required to saturate the sensor. That is called the full well capacity, or simply, maximum signal capacity. With data on the lowest noise to the highest signal, we can then determine the dynamic range of the sensor.
The data and analysis results below show how the canon 5D Mark II sensor performs. Table 1 shows the results and these results are shown on the graphs at Digital Sensor Performance summary for comparison with other cameras.
Table 1
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Apparent Maximum Measured
ISO Gain Read Noise signal Dynamic range
e/DN (electrons) (electrons) stops
50 4.2 24.2 65700 11.41
100 4.1 23.5 59400 11.30
200 2.03 11.9 29700 11.20
400 1.01 6.4 14800 11.18
800 0.51 3.7 7425 10.97
1600 0.25 2.5 3710 10.54
3200 0.127 2.5 1860 9.54
6400 0.063 2.5 930 8.54
12800 0.032 2.5 460 7.54
25600 0.016 230
Pixel pitch: 6.4 microns.
S/N on 18% gray card, ISO 100 = 103.
Sensor Full Well Capacity at lowest ISO: 65,700 electrons.
Sensor dynamic range = 65700/2.5 = 26,280 = 14.7 stops.
ISO at unity gain (scaled to 12 bit) = 1600 (14-bit unity gain = ISO 404).
Low Light sensitivity Factor: 640.
Apparent Image Quality, AIQ = 109
All data derived by R. Clark, December, 2008.
Values in the above table are described at Digital Sensor Performance summary.
Table 2 shows the noise as a funnction of ISO in image form. The images illustrate several things: 1) lower banding noise at higher ISOs. 2) Better detection of smaller signals at higher ISOs (the random noise decreases). 3) At a certainl high ISO, improvements decrease, meaning there is no benefit to higher ISO. Note, ISO is a post sensor gain and does not increase sensitivity. Increasing ISO digitizes a smaller range (see Table 1) but does improve the noise floor up to a point. Some will find the pattern noise objectionable in ISO 1600 images in shadow areas and night photography. At lower ISOs, the pattern nosie is particularly bad. There is still significant pattern noise at the highest ISOs. For night and low light photography, I usually use ISO 3200 with this camera.
| Table 2a. Apparent Read Noise, Central Image | |
 | ISO 50 Image Range: -20.00 to 20.00 electrons about the mean Central 500 x 300 pixel statistics: min= 6972 electrons max= 7385 electrons mean= 7170 electrons standard deviation= 44.54 electrons |
 | ISO 100 Image Range: -20.00 to 20.00 electrons about the mean Central 500 x 300 pixel statistics: min= 6799 electrons max= 7209 electrons mean= 7006 electrons standard deviation= 43.33 electrons |
 | ISO 200 Image Range: -20.00 to 20.00 electrons about the mean Central 500 x 300 pixel statistics: min= 3396 electrons max= 3612 electrons mean= 3505 electrons standard deviation= 21.91 electrons |
 | ISO 400 Image Range: -20.00 to 20.00 electrons about the mean Central 500 x 300 pixel statistics: min= 1669 electrons max= 1826 electrons mean= 1752 electrons standard deviation= 11.57 electrons |
 | ISO 800 Image Range: -20.00 to 20.00 electrons about the mean Central 500 x 300 pixel statistics: min= 817 electrons max= 935 electrons mean= 876 electrons standard deviation= 6.66 electrons |
 | ISO 1600 Image Range: -20.00 to 20.00 electrons about the mean Central 500 x 300 pixel statistics: min= 383 electrons max= 489 electrons mean= 439 electrons standard deviation= 4.47 electrons |
 | ISO 3200 Image Range: -20.00 to 20.00 electrons about the mean Central 500 x 300 pixel statistics: min= 158 electrons max= 277 electrons mean= 220 electrons standard deviation= 4.49 electrons |
 | ISO 6400 Image Range: -20.00 to 20.00 electrons about the mean Central 500 x 300 pixel statistics: min= 48 electrons max= 167 electrons mean= 110 electrons standard deviation= 4.49 electrons |
 | ISO 12800 Image Range: -20.00 to 20.00 electrons about the mean Central 500 x 300 pixel statistics: min= 9 electrons max= 120 electrons mean= 55 electrons standard deviation= 4.42 electrons |
 | ISO 25600 Image Range: -20.00 to 20.00 electrons about the mean Central 500 x 300 pixel statistics: min= 0 electrons max= 91 electrons mean= 28 electrons standard deviation= 4.47 electrons |
| Table 2b. Apparent Read Noise, Full Image, sub-sampled | |
 | ISO 50 Image Range: -20.00 to 20.00 electrons about the mean Full image statistics: min= 6881 electrons max= 10892 electrons mean= 7167 electrons standard deviation= 45.79 electrons |
 | ISO 100 Image Range: -20.00 to 20.00 electrons about the mean Full image statistics: min= 6751 electrons max= 10636 electrons mean= 7003 electrons standard deviation= 44.88 electrons |
 | ISO 200 Image Range: -20.00 to 20.00 electrons about the mean Full image statistics: min= 3369 electrons max= 6939 electrons mean= 3504 electrons standard deviation= 22.54 electrons |
 | ISO 400 Image Range: -20.00 to 20.00 electrons about the mean Full image statistics: min= 1657 electrons max= 5356 electrons mean= 1752 electrons standard deviation= 11.62 electrons |
 | ISO 800 Image Range: -20.00 to 20.00 electrons about the mean Full image statistics: min= 792 electrons max= 4593 electrons mean= 876 electrons standard deviation= 6.88 electrons |
 | ISO 1600 Image Range: -20.00 to 20.00 electrons about the mean Full image statistics: min= 351 electrons max= 4009 electrons mean= 439 electrons standard deviation= 4.66 electrons |
 | ISO 3200 Image Range: -20.00 to 20.00 electrons about the mean Full image statistics: min= 153 electrons max= 3374 electrons mean= 220 electrons standard deviation= 4.60 electrons |
 | ISO 6400 Image Range: -20.00 to 20.00 electrons about the mean Full image statistics: min= 41 electrons max= 1753 electrons mean= 111 electrons standard deviation= 4.56 electrons |
 | ISO 12800 Image Range: -20.00 to 20.00 electrons about the mean Full image statistics: min= 0 electrons max= 868 electrons mean= 55 electrons standard deviation= 4.50 electrons |
 | ISO 25600 Image Range: -20.00 to 20.00 electrons about the mean Full image statistics: min= 0 electrons max= 442 electrons mean= 28 electrons standard deviation= 4.58 electrons |
References
1) CCD Gain. http://spiff.rit.edu/classes/phys559/lectures/gain/gain.html
4) http://www.photomet.com/library_enc_fwcapacity.shtml
Notes:
DN is "Data Number." That is the number in the file for each pixel. I'm quoting the luminance level (although red, green and blue are almost the same in the cases I cited).
16-bit signed integer: -32768 to +32767
16-bit unsigned integer: 0 to 65535
Photoshop uses signed integers, but the 16-bit tiff is unsigned integer (correctly read by ImagesPlus).
The sensor analysis was done with custom, in-house written software. Raw data were extracted from the camera raw files using DCRAW. Custom software read that data and all processing was done in 32-bit floating point.
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http://www.clarkvision.com/reviews/evaluation-canon-1dii
First published December 2010.
Last updated November 17, 2013.