Tuesday, August 28, 2012

Why I Don't Like Noise Reduction

With NR

Without NR

Here's a shot I took of my boss yesterday. Camera was set at 6400 ISO, using my Mir-20 lens, which is a Russian built 20mm (my APS-C sensor turns this into 20 x 1.6 = 32mm). I was using Aperture Priority with the lens opened to it's widest aperture of 3.5. I always keep my in-camera Noise Reduction turned off, and this was simply shot as a Medium JPEG (no RAW). I'm just trying to avoid RAW for awhile, coz Ken Rockwell says I don't need it (hah!) I had pre-focussed the lens while Merlin was busy having a bath by slightly front-focusing ahead of that "splack" on the wall, thinking this would be the best focus point for his eyes if I could get him to look up - turns out this was just right. I said "Boss, Boss" a couple of times and he looked up - that's when I took the shot. The shutter speed turned out to be 1/30.

Here is where personal preference comes in - I noticed the picture is pretty noisy - as expected at ISO 6400, but I sure like the detail that came through around Merlin's eyes and nose. As an experiment, I used Photivo to try some noise reduction. I was heavy handed with it, because all the "good" camera review sites suggest that at high ISO, you have to be to get a technically "good" picture. I personally prefer this without NR - just let the camera, and Merlin, and my bad housekeeping be themselves.

Noise Reduction is for cleaning things up - sometimes it makes things better - I used it in my night photos, but I leave it switched off in my camera, just to give me the choice of introducing it in Post Processing, because it tends to turn the noise speckles into blotches - that is how it works. Also, in your camera, only one NR algorithm is used. PP software like Photivo give you a choice of 9 different methods, with various sliders to vary the effectiveness, depending on the method used.

The Boss says "leave good enough alone!"

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