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#1
February 28th 08, 11:38 PM
posted to rec.photo.digital.slr-systems
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Interesting comparison (300D/40D)
http://www.diwa-labs.com/photoalbum/...=org&id=191587
http://www.diwa-labs.com/photoalbum/...=org&id=191662 
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#2
February 28th 08, 11:39 PM
posted to rec.photo.digital.slr-systems
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Interesting comparison (300D/40D)
Sorry, meant D300.
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#3
February 29th 08, 12:12 AM
posted to rec.photo.digital.slr-systems
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Interesting comparison (300D/40D)
Charles wrote:
http://www.diwa-labs.com/photoalbum/...=org&id=191587 http://www.diwa-labs.com/photoalbum/...=org&id=191662 So what does this mean to you? Note that scale of chart differs - iso 100-1600 (40d), 100-3200 (D300). Note also no explanation of in-camera file format / raw conversion method, where these days raw converters are not born equal. Am I right in thinking that the test results for DR and S/N ratio in channels might explain the apparent low chroma noise of D300?
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#4
February 29th 08, 01:28 AM
posted to rec.photo.digital.slr-systems
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Interesting comparison (300D/40D)
"frederick" wrote in message news:1204243539.202494@ftpsrv1... Charles wrote: http://www.diwa-labs.com/photoalbum/...=org&id=191587 http://www.diwa-labs.com/photoalbum/...=org&id=191662 So what does this mean to you? To me, it means that the twit who did the test doesn't have a clue as to what dynamic range means (which is ((max signal)/(noise floor)), or the log thereof) or how to test it. Simple reality check: Dynamic range must fall by one stop each time the ISO doubles. While this often doesn't hold at low ISOs (due to read noise and circuit noise), it holds at higher ISOs. And this test doesn't show it. David J. Littleboy Tokyo, Japan
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#5
February 29th 08, 04:07 AM
posted to rec.photo.digital.slr-systems
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Interesting comparison (300D/40D)
On Feb 28, 6:38 pm, "Charles" wrote:
http://www.diwa-labs.com/photoalbum/...=org&id=191662 How come these measurements vary from test venue to test venue? I thought the measurement of them was done in some uniform way?
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#6
February 29th 08, 04:10 AM
posted to rec.photo.digital.slr-systems
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Interesting comparison (300D/40D)
On Feb 28, 8:28 pm, "David J. Littleboy" wrote:
"frederick" wrote in message news:1204243539.202494@ftpsrv1... Charles wrote: http://www.diwa-labs.com/photoalbum/...=org&id=191587 http://www.diwa-labs.com/photoalbum/...=org&id=191662 So what does this mean to you? To me, it means that the twit who did the test doesn't have a clue as to what dynamic range means (which is ((max signal)/(noise floor)), or the log thereof) or how to test it. Simple reality check: Dynamic range must fall by one stop each time the ISO doubles. While this often doesn't hold at low ISOs (due to read noise and circuit noise), it holds at higher ISOs. And this test doesn't show it. David J. Littleboy Tokyo, Japan Who are these people? http://www.diwa-awards.com/about
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#7
February 29th 08, 04:57 AM
posted to rec.photo.digital.slr-systems
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Interesting comparison (300D/40D)
"RichA" wrote: On Feb 28, 8:28 pm, "David J. Littleboy" wrote: "frederick" wrote in message news:1204243539.202494@ftpsrv1... Charles wrote: http://www.diwa-labs.com/photoalbum/...=org&id=191587 http://www.diwa-labs.com/photoalbum/...=org&id=191662 So what does this mean to you? To me, it means that the twit who did the test doesn't have a clue as to what dynamic range means (which is ((max signal)/(noise floor)), or the log thereof) or how to test it. Simple reality check: Dynamic range must fall by one stop each time the ISO doubles. While this often doesn't hold at low ISOs (due to read noise and circuit noise), it holds at higher ISOs. And this test doesn't show it. Who are these people? http://www.diwa-awards.com/about Clearly people who blithely use bad tests without thinking... David J. Littleboy Tokyo, Japan
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#8
March 1st 08, 01:05 AM
posted to rec.photo.digital.slr-systems
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Interesting comparison (300D/40D)
"David J. Littleboy" wrote in message ... "RichA" wrote: On Feb 28, 8:28 pm, "David J. Littleboy" wrote: "frederick" wrote in message news:1204243539.202494@ftpsrv1... Charles wrote: http://www.diwa-labs.com/photoalbum/...=org&id=191587 http://www.diwa-labs.com/photoalbum/...=org&id=191662 So what does this mean to you? To me, it means that the twit who did the test doesn't have a clue as to what dynamic range means (which is ((max signal)/(noise floor)), or the log thereof) or how to test it. Simple reality check: Dynamic range must fall by one stop each time the ISO doubles. While this often doesn't hold at low ISOs (due to read noise and circuit noise), it holds at higher ISOs. And this test doesn't show it. Who are these people? http://www.diwa-awards.com/about Clearly people who blithely use bad tests without thinking... David J. Littleboy Tokyo, Japan DIWA or DxO or both? DxO seems to be valid.
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#9
March 1st 08, 12:00 PM
posted to rec.photo.digital.slr-systems
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Interesting comparison (300D/40D)
David J. Littleboy wrote:
"frederick" wrote in message Charles wrote: http://www.diwa-labs.com/photoalbum/...=org&id=191587 http://www.diwa-labs.com/photoalbum/...=org&id=191662 So what does this mean to you? To me, it means that the twit who did the test doesn't have a clue as to what dynamic range means (which is ((max signal)/(noise floor)), or the log thereof) or how to test it. To me, it means it's a case of "meaningless", since the test is not described well enough for others to repeat it. IOW: completely worthless. Simple reality check: Dynamic range must fall by one stop each time the ISO doubles. Must it? Really? Is there no possibility that, say, a converter with finite bits of precision, limits the dynamic range? Or from RAW to JPEG (in camera?) or whatever? Is there no possibility of the definition of "noise floor" to be ... wrong, I mean, different, in that 'test' due to noise smoothing? (If you talk about every day performance, noise supression does play a role!) The 40D seems to deliver ~9 stops between ISO 100 and 1600: http://www.dpreview.com/reviews/canoneos40d/page20.asp (which obviously talks about JPEG, since RAW is discussed below). What I see from Charles' curves is that whatever the limitation may be, it is probably not the sensor. (But then a camera _is_ more than the sensor.) -Wolfgang [1] captured electrons to digital values
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#10
March 1st 08, 12:43 PM
posted to rec.photo.digital.slr-systems
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Interesting comparison (300D/40D)
"Charles" wrote: "David J. Littleboy" wrote: "RichA" wrote: On Feb 28, 8:28 pm, "David J. Littleboy" wrote: "frederick" wrote in message news:1204243539.202494@ftpsrv1... Charles wrote: http://www.diwa-labs.com/photoalbum/...=org&id=191587 http://www.diwa-labs.com/photoalbum/...=org&id=191662 Who are these people? http://www.diwa-awards.com/about Clearly people who blithely use bad tests without thinking... DIWA or DxO or both? DxO seems to be valid. I'd guess off hand that DxO is dizzy, and the DIWA folks didn't figure it out... David J. Littleboy Tokyo, Japan
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