Doug Kerr
Well-known member
Often, a we contemplate buying/using one camera (and perhaps lens) vs. another, one consideration is what I will call (intentionally vaguely) 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:
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
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