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How to measure ISO
I have two cameras. At the same ISO, aperture and exposure time one
takes brighter images than the other one. How to measure the real ISO values at which the cameras took the pictures? -- 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 |
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How to measure ISO
On 2015-10-27 19:07:15 +0000, Alfred Molon said:
I have two cameras. At the same ISO, aperture and exposure time one takes brighter images than the other one. What are the sensor differences? How to measure the real ISO values at which the cameras took the pictures? -- Regards, Savageduck |
#3
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How to measure ISO
On 27/10/2015 19:07, Alfred Molon wrote:
I have two cameras. At the same ISO, aperture and exposure time one takes brighter images than the other one. How to measure the real ISO values at which the cameras took the pictures? With my Fuji X-E1 I find I have to push exposure 2/3 stop to get adequate shadow detail. I've found various Canon compacts to be fine. This of course is for "average" scenes, others are likely to need adjustment anyway. I don't really see the relevance of ISO. Obviously, one or other cameras (or both) don't meet the standard, but provided you have an exposure adjustment dial it is just a question of learning your camera (given that you probably have personal tastes in both subject matter and presentation). Or are you saying that you have a camera without such an adjustment, and you are trying to demonstrate that it is faulty? |
#4
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How to measure ISO
In article ,
newshound says... Or are you saying that you have a camera without such an adjustment, and you are trying to demonstrate that it is faulty? I meant that these two cameras, if set at the same ISO value, aperture and exposure time should deliver an image with the same brightness value. But one of the cameras creates a brighter image, even in RAW (if applying the same RAW conversion parameters). In other words either the ISO 100 of one camera is in reality an ISO 80 or an ISO 125 and the other camera is accurate, or both cameras deviate a bit from the ISO. -- 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 |
#5
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How to measure ISO
In article , Alfred
Molon wrote: Or are you saying that you have a camera without such an adjustment, and you are trying to demonstrate that it is faulty? I meant that these two cameras, if set at the same ISO value, aperture and exposure time should deliver an image with the same brightness value. But one of the cameras creates a brighter image, even in RAW (if applying the same RAW conversion parameters). In other words either the ISO 100 of one camera is in reality an ISO 80 or an ISO 125 and the other camera is accurate, or both cameras deviate a bit from the ISO. lots of cameras cheat. |
#6
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How to measure ISO
On 2015-10-28 15:48, Alfred Molon wrote:
In article , newshound says... Or are you saying that you have a camera without such an adjustment, and you are trying to demonstrate that it is faulty? I meant that these two cameras, if set at the same ISO value, aperture and exposure time should deliver an image with the same brightness value. But one of the cameras creates a brighter image, even in RAW (if applying the same RAW conversion parameters). In other words either the ISO 100 of one camera is in reality an ISO 80 or an ISO 125 and the other camera is accurate, or both cameras deviate a bit from the ISO. Back when I bothered to read dpreview there was lots of mention on the disparity of ISO sensitivity between camera makers or even cameras from the same co. Whether this is due to their interpretation of the method, sensor design or optimization to make particular models stand out at a given ISO number is anyone's guess. And it is not at all important. You can do a standard candle test, if you like. Shoot a grey card in direct sunlight. Should give you a sunny-16 exposure. Deviance from that represents "error". That said, the variance in grey cards that I have spans a full stop or more... What is important is testing your camera in various lighting situations, understanding its metering system and if you're a noise-peeper figuring out what ISO is the quietest. (On my preferred camera that would be ISO 160). |
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How to measure ISO
In article , Alan Browne
says... You can do a standard candle test, if you like. Shoot a grey card in direct sunlight. Well, the sun light strength may differ depending on the day of the year and the geographical location. -- 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 |
#8
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How to measure ISO
On 2015-10-30 03:10, Alfred Molon wrote:
In article , Alan Browne says... You can do a standard candle test, if you like. Shoot a grey card in direct sunlight. Well, the sun light strength may differ depending on the day of the year and the geographical location. That is true enough but it's also one of the sole independent tests you can do absent a lab with the right equipment. |
#9
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How to measure ISO
On Tue, 27 Oct 2015 20:07:15 +0100, Alfred Molon
wrote: I have two cameras. At the same ISO, aperture and exposure time one takes brighter images than the other one. How to measure the real ISO values at which the cameras took the pictures? Shoot a grey scale using sunny sixteen values, maybe. |
#10
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How to measure ISO
On Tue, 27 Oct 2015 20:07:15 +0100, Alfred Molon
wrote: I have two cameras. At the same ISO, aperture and exposure time one takes brighter images than the other one. How to measure the real ISO values at which the cameras took the pictures? Borrow or rent an external light meter, compare the values. Then you can have three variables. |
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