Know Your Noise

February 5, 2010

I’ve just begun messing around with a Nikon Coolpix P60. This was one of Nikon’s upper-level point & shoots from back in 2008.

It’s not the greatest camera in its class, and it’s not the worst. For a pocketable 8 megapixel model, the P60 is probably about average.

Nikon Coolpix P60

Nikon Coolpix P60

Its pixels are about 1.9 microns across; today, 1.5 or 1.4 microns has become the norm. In other words, the P60’s pixels have 60-80% more light-gathering area than the ones used in a typical 2010 compact.

So let’s take a quick look at how well it handles noise.

We’ll start with an image where the camera is set to ISO 80, the lowest available. And I’ve zoomed to 135e, for a close view of my (charming) model:

P60 ISO 80 Close-Up

Click for Larger Version

This is the high-quality version, to show us what the textures and details ought to look like. (Although notice that the P60, like any small-pixel camera, is struggling to keep the highlights from blowing out.)

Now we zoom out the lens, and look at some detail crops to see how well the image quality holds up. Here’s the same view of the subject, at ISO 80, ISO 200, and ISO 800 (these are now crops using about 40% of the frame width).

It’s not a huge surprise that ISO 800 looks very grainy:

ISO 800 Crop 1, at 100%

100% view, ISO 800

The top of the camera no longer shows its original texture; any apparent detail is just the noise itself.

P60 Crop 2 at ISO 800

Subtle Details Getting Lost in Noise

While at ISO 80 you could still read “München Germany” below the lens, that detail is gone now.

But let’s give Nikon some credit: Chroma noise is very well controlled here, so the speckles do not have distracting “rainbow confetti” colors. Aesthetically, this noise is fairly inoffensive.

However, what may be more worrying is that even at a moderate ISO 200, we still see some anomalies:

P60 Crop 1 at ISO 200

100% View, ISO 200

Instead of obvious noise, the issue is more subtle here: Rather than looking entirely photographic, the image almost begins to look painted. Noise-reduction processing has kicked in, even at a fairly low ISO—and it’s adding some of its own odd artifacts.

P60 Crop 2 at ISO 200

A "Watercolors" Look in the Lens Reflections

Remember—ideally, it’s supposed to look like this:

Lens Detail, Good Original

Back to the Original

Of course, this “painterly” impression is much less noticeable at any reasonable viewing size. We’re pixel-peeping here.

Yet there’s something troubling about a camera that re-draws your photographs—even if it does so very tastefully.


One Response to “Know Your Noise”

  1. […] had a chance to take some sample shots with the 8-megapixel Nikon Coolpix P60, using the resolution test target I posted last week. (Open a tab to remind yourself how the target […]

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