Originally posted by falconeye For the question of usefulness: equivalence reduces four parameters (focal length, fstop, iso, sensor size) into three parameters (field of view, aperture, noiselevel)
Nice!
Also, there is not only a reduction in number of parameters, but the three remaining parameters are more closely aligned with that a photographer should really care about
:
field of view -> framing
aperture -> DOF
noiselevel -> Image IQ
In contrast, the traditional parameters have a more technical orientation:
focal length -> optical power of the lens (allows inferring framing, if the sensor size is constant)
fstop -> exposure [in combination with shutter speed] (allows inferring noise-level, if the sensor size is kept constant; and DOF if, in addition, focal length is kept constant as well)
iso -> exposure compensation (may indicate level of under- or over-exposure, if the sensor size is kept constant)
sensor size -> influences the photographic relevance of all of the above.
Last edited by Class A; 07-23-2015 at 06:47 AM.