2017-01-12 18:17 GMT+01:00 Bob Benson <bob.benson91@xxxxxxxxx>:
> I've been puzzling over m4/3 vs. FF for a while. I'm hoping Moose/AG, etal
> can help me.
>
> My question now is stimulated by a recent camera review that stated "FF
> sensors collect 4 times as much information as M4/3" ... presumably based
> on the difference in sensor size. My initial response: "really" ?
>
Lets give it a try ;-). A FF sensor collects 4 times as much *light* as
M43 (that is just about photons and surface). But what was the definition
of information? Resolution or (also) light-intensity?
Probably a bit simplified but that light only equals 4 times as much
resolution if
a) the FF sensor has 4 times the pixels and
b) the lens used on FF resolves 4 times the resolution of the M43 lens.
With comparable sensor technology of course.
From a visual perspective this will be perceived as twice the information,
since it is 2 times in horizontal direction and 2 times in vertical. A 100%
pixel view will be twice the size on your screen.
In real life, the current FF Mp champion has 50 Mp, and M43 champion 20 Mp.
Therefor, the FF pixels are bigger and therefor the FF sensors have
advantages like increased dynamic range, less noise at comparable ISO, etc.
FF will have 4 times more 'energy-levels', meaning 2 bits more per pixel.
Again with comparable sensor technology.
>
> My question has two parts.
>
> 1. For FF and M/43 sensors with the same pixel count, say 20meg, is the
> actual amount of information collected significantly different? (I think I
> understand the issues of dynamic range and LOF and high ISO noise, but I'd
> thought these are artifacts of the circuits and lenses used, not the amount
> of information per se.) I suppose this is the same question: for FF and
> M/43 with the same pixel count, would the RAW files be the same size?
>
The RAW files could be the same size (apart from compression), but the FF
might save these 2 bits more per pixel.
>
> 2. As FF sensors increase in pixel count, say to 60meg, will they begin to
> exhibit similar issues of dynamic range and high ISO noise because of the
> density of the circuits approaching that of the m4/3 sensors?
>
In theory, why not. However, you might need 4 times the energy for reading
the sensor and computing the RAW file (and JPEG), and I'm not sure the
resulting heat is just as easy to handle as with a smaller sensor. If you
want to do it in the same time (performance) you might need 4^2 times the
energy? Maybe that costs some dynamic range, and it definitely would affect
high ISO noise.
Curious about Moose's comments ;-)
Oh and from a user point of view, since I both use M43 (16 Mp) and FF (Sony
24 Mp). Is FF 4x better then M43? Don't think so. However it depends on
what you need and expect. There might be areas where FF indeed is 4x better
then M43 (however I don't know them). But I doubt it will be a big % of any
photographers need ;-)
--
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