sin77 said:but since the barrel is bigger, doesn't it means more light will reach the sensor and hence higher shutter speed?
but since the barrel is bigger, doesn't it means more light will reach the sensor and hence higher shutter speed?
Aperture area[edit]
The amount of light captured by a lens is proportional to the area of the aperture, equal to:
Where f is focal length and N is the f-number.
The focal length value is not required when comparing two lenses of the same focal length; a value of 1 can be used instead, and the other factors can be dropped as well, leaving area proportion to the reciprocal square of the f-number N.
If two cameras of different format sizes and focal lengths have the same angle of view, and the same aperture area, they gather the same amount of light from the scene. In that case, the relative focal-plane illuminance, however, would depend only on the f-number N, so it is less in the camera with the larger format, longer focal length, and higher f-number. This assumes both lenses have identical transmissivity.
barrel is bigger.......... like 大支就好? lol.but since the barrel is bigger, doesn't it means more light will reach the sensor and hence higher shutter speed?
but since the barrel is bigger, doesn't it means more light will reach the sensor and hence higher shutter speed?
but since the barrel is bigger, doesn't it means more light will reach the sensor and hence higher shutter speed?
but since the barrel is bigger, doesn't it means more light will reach the sensor and hence higher shutter speed?
I can see where you are confused.
1. Yes, it is true that APS-C will have more light going in at f2.8 than m4/3 going in at f2.8
However APS-C lens will have to illuminate the entire APS-C sensor, while the m4/3 will only have to illuminate the m4/3 sensor. So it is the same shutter speed at the same ISO and aperture as explained in so many of the above posts already.
2. Now, since APS-C captures more light than m4/3 sensor, all things being equal (i.e. the sensors are the same), it would mean that there would be less noise with APS-C than M4/3.
As such, I think you are not asking the right question and thus, confusing yourself with the answer you want to hear.
3. Barrel has nothing to do with it - I'm not even sure what you mean by "barrel". If you mean the physical size, then I would personally prefer a smaller barrel for the same max aperture (f-stop) lens. f1.4 is f1.4, irregardless of size. However, I think what you mean is APS-C f1.4 vs m4/3 f1.4...which will be confusing.