Should You Use In Camera Noise Reduction Or Not?

460x150-Banner-Box Should You Use In Camera Noise Reduction Or Not?

This is another common question on many user groups. It comes up time and time again. But really there is no one clear cut answer. In a perfect world we would never need to add any noise reduction, but we don’t live and shoot in a perfect world. Often a camera might be a little noisy or you may be shooting with a lot less light than you would really like, so in camera NR might need to be considered.

You need to consider carefully whether you should use in camera NR or not. There will be some cases where you want in camera NR and other times when you don’t.

Post Production NR.
An important consideration is that adding post production NR on top of in-camera NR is never the best route to go down. NR on top of NR will often produce ugly blocky artefacts. If you ever want to add NR in post production it is almost always better not to also add in camera NR. Post production NR has many advantages as you can more precisely control the type and amount you add depending on what the shot needs. When using proper grading software such as DaVinci Resolve you can use power windows or masks to only add NR to the parts of the image that need it.

Before someone else points it out I will add here that it is almost always impossible to turn off all in camera NR. There will almost certainly be some NR added at the sensor that you can not turn off. In addition most recording codecs will apply some noise reduction to avoid wasting data recording the noise, again this can’t be turned off. Generally higher bit rate, less compressed codecs apply less NR. What I am talking about here is the additional NR that can be set to differing levels within the cameras settings that is in addition to the NR that occurs at the sensor or in the codec.

Almost every NR process, as well as reducing the visibility of noise will introduce other image artefacts. Most NR process work by taking an average value for groups of pixels or an average value for the same pixel over a number of frames. This averaging tends to not only reduce the noise but also reduce fine details and textures. Faces and skin tones may appear smoothed and unnatural if excessively noise reduced. Smooth surfaces such as walls or the sky may get broken up into subtle bands or steps. Sometimes these artefacts won’t be seen in the cameras viewfinder or on a small screen and only become apparent on a bigger TV or monitor. Often the banding artefacts seen on walls etc are a result of excessive NR rather than a poor codec etc (although the two are often related as a weak codec may have to add a lot of NR to a noisy shot keep the bit rate down).

If you are shooting log then any minor artefacts in the log footage from in camera noise reduction may be magnified when you start grading and boosting the contrast. So, generally speaking when shooting log it is always best to avoid adding in camera NR. The easiest way to avoid noise when shooting with log is to expose a bit brighter so that in the grade you are never adding gain. Take gain away in post production to compensate for a brighter exposure and you take away much of the noise – without giving up those fine textures and details that make skin tones look great. If shooting log, really the only reason an image will be noisy is because it hasn’t been exposed bright enough. Even scenes that are meant to look dark need to be exposed well. Scenes with large dark areas need good contrast between at least some brighter parts so that the dark areas appear to be very dark compared to the bright highlights. Without any highlights it’s always tempting to bring up the shadows to give some point of reference. Add a highlight such as a light fixture or a lit face or object and there is no need to then bring up the shadows, they can remain dark, contrast is king when it comes to dark and night scenes.

If, however you are shooting for “direct to air” or content that won’t be graded and needs to look as good as possible directly from the camera then a small amount of in camera NR can be beneficial. But you should test the cameras different levels to see how much difference each level makes while also observing what happens to subtle textures and fine details. There is no free lunch here. The more NR you use the more fine details and textures you will lose and generally the difference in the amount of noise that is removed between the mid and high setting is quite small. Personally I tend to avoid using high and stick to low or medium levels. As always good exposure is the best way to avoid noise. Keep your gain and ISO levels low, add light if necessary or use a faster lens, this is much more effective than cranking up the NR.

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