Dark comparison Canon D60 to several Canon 10D
300 sec at ISO 800 at +22°C in jpg-fine, WB-auto
The image at right shows 4 darks (vertically cropped, no stretch) from different camera models at 50% size:
Top: my 10D at 26C (serial 0620...)
next: an older 10D (serial 0320...)
next: a newer 10D (serial 0420...)
Bottom: My old D60
The comparison shows that the amplifier glowing from the D60 has been completely eliminated for the 10D; the uniform noise is bad for the 0320... model,
most of the newer 10D models are showing significantly lower noise than the D60 models for bulb exposures.
ATTENTION: also some newer models show high noise, so a comparison test at the shop is recommended, use ISO1600 and 300 sec bulb exposure with the cap on for comparison and check the histogramm.
The major part of this residual noise can be subtracted by taking dark frames.
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Noise at different ISO ratings
All images are 300 sec darks (center crops) at 22°C in jpg-fine, WB-auto
ISO100
statistics (Astroart):
background: 0
average: 0.67
st.dev.: 0.86
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ISO200
statistics (Astroart):
background: 1
average: 0.90
st.dev.: 1.05
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ISO400
statistics (Astroart):
background: 2
average: 1.57
st.dev.: 1.38
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ISO800
statistics (Astroart):
background: 2
average: 2.14
st.dev.: 2.20
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ISO1600
statistics (Astroart):
background: 1
average: 2.66
st.dev.: 5.20
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Dark frame comparison animation
The above darks have been stretched to give all the same light efficiency:
ISO100 multiplied x 16: average 11.8 st.dev. 11.5
ISO200 multiplied x 8: average 7.5 st.dev. 7.2
ISO400 multiplied x 4: average 6.2 st.dev. 5.0
ISO800 multiplied x 2: average 4.3 st.dev. 4.3
ISO1600 left as it is: average 2.7 st.dev. 5.2
The comparison shows that the best S/N ratio should be obtained at high ISO settings (800-1600); lower ISO settings supply more green background.
For the D60 I found a more equal noise level at different ISO settings. The ISO3200 setting should not be used, too noisy and too little dynamic.
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Dark frame comparison at 0 degree C in jpg-fine
The performance of the camera at lower temperature increases significantly:
A test series 300sec at ISO1600 shows st.dev. 2.5-3
The animation shows the noise buid-up at consecutive shooting and a 10x averaged image
Save and view the animation at 200% size for better details.
Noise stays quite low during the shooting, averaging at these conditions does not reduce the noise significantly, see the Veil raw at 0C for comparison.
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In raw mode the best S/N can be reached. Again the dependance of noise on the ambient temperature is very obvious.
On the right side there is a link to a graph of dark noise for 22C and -4C. In contrary to cooled CCD the reduction of noise within this temperature span is 40-50% against 50% reduction for each 6C decrease on typical CCD cameras.
Dark subtraction at temperaures below 0C in raw mode is no more very effective (same as in jpg mode), as only a few hot pixels remain in the raws, the residual noise is more random like.
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A wide field single raw exposure of M17 with the 4" refractor at f/5 and the UHC filter
The UHC filter improves the nebula structure a lot, this is valid for most emission nebulae
300 sec at ISO800, WB sunny, temperature +20 degree C
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raw frame at 50% size
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raw center at 100% size
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A wide field single raw exposure of NGC6992 with the 4" refractor at f/5 and the UHC filter
300 sec at ISO1600, WB sunny, temperature 0 degree C - noise decreased significantly
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raw frame at 50% size
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raw crop at 100% size
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An exposure of M57 with the C11 at f/10
120 sec at ISO800, WB sunny, temperature +15 degree C
comparing the 2 images drastically shows the big step from a raw to the final product
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single raw at 100% size
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20 x 120 sec processed
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First light for the Canon 300 mm f/2.8 L USM lens aimed at Comet 2P/Encke near M31
ISO800, WB sunny, temperature 0 degree C, lens fully open
The very high quality of the lens provides round stars even at the corners with moderate chromatic aberration
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single 60 sec raw at 100% size
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3 x 180 sec processed at 50%
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Again a raw-final comparison on a crop of M42/43 with the 4" TMB refractor at f/5
Data for the raw file: unfiltered, ISO400, WB sunny, temperature -4 degree C
Both crops are 100% size, the raw is a 300 sec exposure without any touching just out of the camera;
The processed image contains 26x5 min, 8x60 sec and 2x10 sec exposures at ISO200 - ISO400
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single 300 sec raw crop
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processed image
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