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#11
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The base ("native") ISO of a sensor
In article ,
RichA wrote: The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a bit less dynamic range) but the highest dynamic range at ISO 200. So what would be the native or base ISO of the sensor? How would that be defined? The "base" would be the ISO where the analog and digital gain are both 1 (0 dB). I've never seen a camera maker publish that. The analog gain stage is a noise source in itself - even at 0 dB - but unavoidable. For my cameras (DSLR's) the base appears to be ISO 160 based on various noise graphs. But frankly anywhere from 100 to 400 appears the same in normal viewing. 800 and shadow noise is discernible in processing at 100% zoom but invisible in prints or display. Although this post disputes what I wrote above - a lot to learn there. http://www.clarkvision.com/articles/....summary/#unit y_gain One post here (by a noted astronomical CCD camera expert) says there is no such thing as native ISO because there is amplification at every ISO. http://www.tomsguide.com/forum/30791...-native-sensor that's a thread from this newsgroup and the ccd camera expert is roger clark, who used to post here and owns clarkvision.com and authored the previous link. |
#12
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The base ("native") ISO of a sensor
On 27/05/2017 6:32 AM, Alfred Molon wrote:
In article , Me says... On 26/05/2017 5:50 PM, nospam wrote: In article , Sandman wrote: The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a bit less dynamic range) but the highest dynamic range at ISO 200. So what would be the native or base ISO of the sensor? How would that be defined? Unless the camera maker doesn't specify this specifically, there is no way to know when the sensor output is boosted or not. there is. Yes. and also the comment that: "The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a bit less dynamic range) makes no sense. Anyway, as Scotty said - "Ye cannae change laws of physics" http://photonstophotos.net/Charts/PD...M1%20Mark%20II But wait - Olympus appears to have done so. So either they're bull****ting about actual ISO setting (which they've done before) or bull****ting by applying noise reduction to raw files (which they've also done before), or bull****ting about both (likely). So if you /think/ when it's set at ISO 6400 - it actually is, and you /think/ there's no NR applied to raw files, and are happy with the result, then enjoy. ... what have you been smoking? You don't believe that if something tests better than the laws of physics dictate is possible, then some trickery or deception is going on? Sure it could be "error" by the manufacturer - but they seem to always err on the side of making the camera seem to perform better than it really does rather than worse - it is deliberate. In the link I posted above, then the plot for "ideal 4/3" format assumes that every pixel is captured and recorded and there's no read noise / electronic noise degrading the dynamic range. Yet that camera appears to perform better than is possible - better than "ideal". The loss of dynamic range as ISO increases is inevitable "shot noise" - there's nothing that can be done to avoid it. |
#13
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The base ("native") ISO of a sensor
On 27/05/2017 2:54 PM, Me wrote:
On 27/05/2017 6:32 AM, Alfred Molon wrote: In article , Me says... On 26/05/2017 5:50 PM, nospam wrote: In article , Sandman wrote: The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a bit less dynamic range) but the highest dynamic range at ISO 200. So what would be the native or base ISO of the sensor? How would that be defined? Unless the camera maker doesn't specify this specifically, there is no way to know when the sensor output is boosted or not. there is. Yes. and also the comment that: "The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a bit less dynamic range) makes no sense. Anyway, as Scotty said - "Ye cannae change laws of physics" http://photonstophotos.net/Charts/PD...M1%20Mark%20II But wait - Olympus appears to have done so. So either they're bull****ting about actual ISO setting (which they've done before) or bull****ting by applying noise reduction to raw files (which they've also done before), or bull****ting about both (likely). So if you /think/ when it's set at ISO 6400 - it actually is, and you /think/ there's no NR applied to raw files, and are happy with the result, then enjoy. ... what have you been smoking? You don't believe that if something tests better than the laws of physics dictate is possible, then some trickery or deception is going on? Sure it could be "error" by the manufacturer - but they seem to always err on the side of making the camera seem to perform better than it really does rather than worse - it is deliberate. In the link I posted above, then the plot for "ideal 4/3" format assumes that every pixel is captured and recorded and there's no read noise / electronic noise degrading the dynamic range. Yet that camera appears to perform better than is possible - better than "ideal". The loss of dynamic range as ISO increases is inevitable "shot noise" - there's nothing that can be done to avoid it. Oh nice. Bill Claff has produced an interactive chart showing comparison between set ISO and measured ISO. Olympus OMD E1 MkII overstates real ISO by 1.23 stops! Something many fanboys won't want to accept I guess - those ISO3200 shots are actually only ISO 1365 - LOL. He's also measured base/native ISO is ISO 200. http://photonstophotos.net/Charts/Measured_ISO.htm |
#14
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The base ("native") ISO of a sensor
In article , Me says...
Oh nice. Bill Claff has produced an interactive chart showing comparison between set ISO and measured ISO. Olympus OMD E1 MkII overstates real ISO by 1.23 stops! Something many fanboys won't want to accept I guess - those ISO3200 shots are actually only ISO 1365 - LOL. He's also measured base/native ISO is ISO 200. http://photonstophotos.net/Charts/Measured_ISO.htm He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II. But the exposure time at ISO 64 is three times longer than at ISO 200, so clearly this Bill Claff is wrong. -- Alfred Molon Olympus E-series DSLRs and micro 4/3 forum at http://tech.groups.yahoo.com/group/MyOlympus/ http://myolympus.org/ photo sharing site |
#15
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The base ("native") ISO of a sensor
On 27/05/2017 5:19 PM, Alfred Molon wrote:
In article , Me says... Oh nice. Bill Claff has produced an interactive chart showing comparison between set ISO and measured ISO. Olympus OMD E1 MkII overstates real ISO by 1.23 stops! Something many fanboys won't want to accept I guess - those ISO3200 shots are actually only ISO 1365 - LOL. He's also measured base/native ISO is ISO 200. http://photonstophotos.net/Charts/Measured_ISO.htm He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II. But the exposure time at ISO 64 is three times longer than at ISO 200, so clearly this Bill Claff is wrong. DXO say the same, so no, Bill Claff is not wrong: https://www.dxomark.com/Cameras/Comp..._1136_1070_909 Olympus lie about ISO. Big lies - Trump style lies. |
#16
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The base ("native") ISO of a sensor
In article , Me says...
On 27/05/2017 5:19 PM, Alfred Molon wrote: In article , Me says... Oh nice. Bill Claff has produced an interactive chart showing comparison between set ISO and measured ISO. Olympus OMD E1 MkII overstates real ISO by 1.23 stops! Something many fanboys won't want to accept I guess - those ISO3200 shots are actually only ISO 1365 - LOL. He's also measured base/native ISO is ISO 200. http://photonstophotos.net/Charts/Measured_ISO.htm He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II. But the exposure time at ISO 64 is three times longer than at ISO 200, so clearly this Bill Claff is wrong. DXO say the same, so no, Bill Claff is not wrong: https://www.dxomark.com/Cameras/Comp..._1136_1070_909 Olympus lie about ISO. Big lies - Trump style lies. No. If the exposure time at ISO 64 is *three times* the exposure time at ISO 200, then both ISO settings do not have the same "true ISO" of 83. That is a *fact* and if DXOMark or whoever say otherwise, they are wrong. -- Alfred Molon Olympus E-series DSLRs and micro 4/3 forum at http://tech.groups.yahoo.com/group/MyOlympus/ http://myolympus.org/ photo sharing site |
#17
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The base ("native") ISO of a sensor
In article ,
RichA wrote: On Friday, 26 May 2017 00:08:58 UTC-4, android wrote: In article , RichA wrote: On Thursday, 25 May 2017 18:03:37 UTC-4, Alfred Molon wrote: The Olympus E-M1 II has the lowest noise at ISO 64 (at the cost of a bit less dynamic range) but the highest dynamic range at ISO 200. So what would be the native or base ISO of the sensor? How would that be defined? -- Alfred Molon Olympus E-series DSLRs and micro 4/3 forum at http://tech.groups.yahoo.com/group/MyOlympus/ http://myolympus.org/ photo sharing site Nobody knows. Finding a place where it is pinned-down to a specific sensor is difficult. Likely you'd have better luck finding out in a professional area where CCD and CMOS-based cameras actually have to meet certain specs, unlike the consumer realm. As we all know: The sensors of quarterframe/mFT cameras are silly small. Thus the photon wells are small too! At the lower ISO the wells fills up more and thus the noise is reduced but the room for play at the top of the well gets thiner and then again less dynamic range is found in the files. Again: Bigger is better! :-)) -- teleportation kills And yet...the 36mp FF sensor has the same pixel well-depth as an old 10mp m4/3rds sensor, but no one criticized the D800... https://www.dxomark.com/Cameras/Comp...us-OM-D-E-M1-M ark-II-versus-Canon-EOS-5D-Mark-IV-versus-Nikon-D810___1136_1106_963 Go to the tab "Measurements" and then "Dynamic Range"... You see Olympus quaterframe sensor wells are about half the size of the full frames Nikon and Canons despite their almost double resolution... -- teleportation kills |
#18
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The base ("native") ISO of a sensor
On 28/05/2017 1:31 AM, Alfred Molon wrote:
In article , Me says... On 27/05/2017 5:19 PM, Alfred Molon wrote: In article , Me says... Oh nice. Bill Claff has produced an interactive chart showing comparison between set ISO and measured ISO. Olympus OMD E1 MkII overstates real ISO by 1.23 stops! Something many fanboys won't want to accept I guess - those ISO3200 shots are actually only ISO 1365 - LOL. He's also measured base/native ISO is ISO 200. http://photonstophotos.net/Charts/Measured_ISO.htm He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II. But the exposure time at ISO 64 is three times longer than at ISO 200, so clearly this Bill Claff is wrong. DXO say the same, so no, Bill Claff is not wrong: https://www.dxomark.com/Cameras/Comp..._1136_1070_909 Olympus lie about ISO. Big lies - Trump style lies. No. If the exposure time at ISO 64 is *three times* the exposure time at ISO 200, then both ISO settings do not have the same "true ISO" of 83. That is a *fact* and if DXOMark or whoever say otherwise, they are wrong. Don't be silly. Base ISO (set in camera) is 200 = real ISO 83. This answers your original question about "native" or "base" ISO of the sensor. If you don't want to believe that Olympus OMD EM1 real ISO is 1.23 stops below stated ISO, bully for you. I don't really care. |
#19
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The base ("native") ISO of a sensor
On 28/05/2017 6:52 PM, RichA wrote:
On Saturday, 27 May 2017 04:44:29 UTC-4, Me wrote: On 27/05/2017 5:19 PM, Alfred Molon wrote: In article , Me says... Oh nice. Bill Claff has produced an interactive chart showing comparison between set ISO and measured ISO. Olympus OMD E1 MkII overstates real ISO by 1.23 stops! Something many fanboys won't want to accept I guess - those ISO3200 shots are actually only ISO 1365 - LOL. He's also measured base/native ISO is ISO 200. http://photonstophotos.net/Charts/Measured_ISO.htm He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II. But the exposure time at ISO 64 is three times longer than at ISO 200, so clearly this Bill Claff is wrong. DXO say the same, so no, Bill Claff is not wrong: https://www.dxomark.com/Cameras/Comp..._1136_1070_909 Olympus lie about ISO. Big lies - Trump style lies. DXO is for zombies. They think camera lenses "change their physical shaprness characteristics" with sensor size and resolution. News flash, DXO, they don't. If they had an interferometer, they'd SEE that. " What a load of crap. Give some example, instead of vague waffling, about where and how DXO is wrong. |
#20
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The base ("native") ISO of a sensor
In article ,
RichA wrote: On Saturday, 27 May 2017 04:44:29 UTC-4, Me wrote: On 27/05/2017 5:19 PM, Alfred Molon wrote: In article , Me says... Oh nice. Bill Claff has produced an interactive chart showing comparison between set ISO and measured ISO. Olympus OMD E1 MkII overstates real ISO by 1.23 stops! Something many fanboys won't want to accept I guess - those ISO3200 shots are actually only ISO 1365 - LOL. He's also measured base/native ISO is ISO 200. http://photonstophotos.net/Charts/Measured_ISO.htm He measures ISO 83 both at ISO 64 and ISO 200 with the Olympus E-M1 II. But the exposure time at ISO 64 is three times longer than at ISO 200, so clearly this Bill Claff is wrong. DXO say the same, so no, Bill Claff is not wrong: https://www.dxomark.com/Cameras/Comp...M-D-E-M1-Mark- II-versus-Olympus-PEN-F-versus-Olympus-OM-D-E-M1___1136_1070_909 Olympus lie about ISO. Big lies - Trump style lies. DXO is for zombies. They think camera lenses "change their physical shaprness characteristics" with sensor size and resolution. News flash, DXO, they don't. If they had an interferometer, they'd SEE that. The DxO test cameras and lenses when making profiles for their reputable soft. They share that very useful data. You can think what you like about how they balance their "scores" but the data in graphs and tables is very interesting. -- teleportation kills |
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