08-28-2011, 08:28 AM
[quote name='Yakim' timestamp='1314517572' post='11091']
I'm not sure I follow this. Are you saying that if you mount the same lens on FF and MFT (via adapter) and use the same FL, the same aperture and the same ISO in both bodies you'd get a 2-stop difference in SS? I'm not a technical expert but I think SS will be the same.
Klaus, can you please comment?
[/quote]
No, I am not saying that. Read it again.
Anyway, if one were to use the SAME lens on DIFFERENT sensor sizes, and somehow not care about that the field of view changes.... Then still the sensor is of different size. Suppose one is 135 format ("Full Frame"). And the other of 4/3rds format (2x crop compared to the 135 format sensor). Since the surface of the 4/3rds sensor is just 1/4th of the size of the 135 sensor surface, we do still collect only 1/4th of the light.
To make things easy to understand, lets just suppose each sensor has the same amount of sensels (lets say, 12mp E-30 and 12mp D700). Each sensel of the 4/3rds sensor will also have about 1/4th the size of each sensel of the 135 format sensor. Each sensel of the 4/3rds sensor will collect 1/4th of the light the 135 format sensels collect, for the same exposure time.
The manufacturers compensate these matters by applying amplification to the signal. ISO used to be about sensitivity of film, it is not about sensitivity of the sensor though. It is just a setting that more or less equalizes exposure times over different sensitivity sensors, by applying whatever amplification to reach that point.
So... for the 4/3rds sensor camera to reach the same point, total amplification of the signal will be about 4 times that of the 135 format sensor camera.
To have the SAME amount of amplification. or rather, a similar collected signal, use ISO 100 on 4/3rds and ISO 400 on FF. Or ISO 400 on 4/3rds and ISO 1600 on FF. Equivalent ISO settings.
What I was talking about was equivalent lenses, though... so not the same lens, but a lens that is equivalent. So, if you take the 12mm f4 Oly on 4/3rds, equivalent 135 format lens: 24mm f4. This gives you a similar field of view, and a similar depth of field. If you also care about a similar exposure time, set also the ISO settings to equivalent values: ISO 100 on 4/3rds, ISO 400 on FF.
Now everything will be similar:
* Similar field of view
* Similar DOF
* Similar exposure time
* Similar noise performance (provided the sensor technology is comparable)
I'm not sure I follow this. Are you saying that if you mount the same lens on FF and MFT (via adapter) and use the same FL, the same aperture and the same ISO in both bodies you'd get a 2-stop difference in SS? I'm not a technical expert but I think SS will be the same.
Klaus, can you please comment?
[/quote]
No, I am not saying that. Read it again.
Anyway, if one were to use the SAME lens on DIFFERENT sensor sizes, and somehow not care about that the field of view changes.... Then still the sensor is of different size. Suppose one is 135 format ("Full Frame"). And the other of 4/3rds format (2x crop compared to the 135 format sensor). Since the surface of the 4/3rds sensor is just 1/4th of the size of the 135 sensor surface, we do still collect only 1/4th of the light.
To make things easy to understand, lets just suppose each sensor has the same amount of sensels (lets say, 12mp E-30 and 12mp D700). Each sensel of the 4/3rds sensor will also have about 1/4th the size of each sensel of the 135 format sensor. Each sensel of the 4/3rds sensor will collect 1/4th of the light the 135 format sensels collect, for the same exposure time.
The manufacturers compensate these matters by applying amplification to the signal. ISO used to be about sensitivity of film, it is not about sensitivity of the sensor though. It is just a setting that more or less equalizes exposure times over different sensitivity sensors, by applying whatever amplification to reach that point.
So... for the 4/3rds sensor camera to reach the same point, total amplification of the signal will be about 4 times that of the 135 format sensor camera.
To have the SAME amount of amplification. or rather, a similar collected signal, use ISO 100 on 4/3rds and ISO 400 on FF. Or ISO 400 on 4/3rds and ISO 1600 on FF. Equivalent ISO settings.
What I was talking about was equivalent lenses, though... so not the same lens, but a lens that is equivalent. So, if you take the 12mm f4 Oly on 4/3rds, equivalent 135 format lens: 24mm f4. This gives you a similar field of view, and a similar depth of field. If you also care about a similar exposure time, set also the ISO settings to equivalent values: ISO 100 on 4/3rds, ISO 400 on FF.
Now everything will be similar:
* Similar field of view
* Similar DOF
* Similar exposure time
* Similar noise performance (provided the sensor technology is comparable)