#### Doug Kerr

##### Well-known member

*potential noise performance*.

Simplistically, we know that the greater the luminous energy on each pixel (for any given scene luminance, under "standard exposure" conditions), the better will be the noise performance. As a tactical matter, that means the higher the sensitivity we can employ and still get some certain image quality (from a noise standpoint).

With regard to how different camera-lens combinations will allow us to play this, two properties loom as important (in an "all other things being equal" context):

• The per-pixel area.

• The maximum aperture the lens offers (or the largest aperture we are interested in using based on depth of field and so forth).

We can combine those two into a simple "relative" metric for "potential noise performance" with this equation:

*z*= (

*p*/

*N*)^2

where

*z*is my

*potential noise performance*metric,

*p*is the pixel pitch, in μm, and

*N*is the aperture, as an f-number.

It is interesting to reckon this metric for two of my current cameras, my Panasonic FZ1000 (with a "one inch" sensor and a pixel pitch of 2.41 μm) and my Canon G16 (with a "1/1.7 inch" sensor and a pixel pitch of 1.07 μm).

If we think in terms of operation at the smallest focal length of the lenses on both cameras, where the Z1000 has a maximum aperture of f/2.8 and the G16 has a maximum aperture of f/1.8, then the FZ1000 has z=0.7 and the G16 has z = 1.1, the G16 having a slightly greater

*potential noise performance*.

If now we consider operation at 125 mm ff35e focal length, and again assume operation at the largest possible aperture, the FZ1000 shows

*z*=0.38 and the G16 shows

*z*=0.44. Again, the G16 shows a larger value of

*z*than the FZ1000.

Of course, there is a difference in geometric resolution between these two cameras (with the FZ1000 being a 20 Mpx machine and the G16 12 Mpx), so we certainly can't conclude that the G16 is a better "low light" camera. But the comparison in terms of the metric I discuss here is interesting.

Now for a further comparison, for a Canon EOS M50, equipped with the infamous EF-M 22 mm f/2.0 lens (ff35e 35 mm), we get

*z*=3.5, suggesting (at that focal length!) a superior noise performance potential.

Of course, the reason I include the modifier "potential" here is that this is a rather naïve estimation of noise performance. But I think useful.

Best regards,

Doug