High ISO Imaging
16 June 2017
Portrait of female Crested Fireback shot in difficult conditions in a thick undergrowth of virgin rainforest (nervous bird seldom in full view, moving erratically) at 1/160 sec. and 650 mm (ISO 8000); open in lightbox to see info on crop
Suitably handled noise reduction and character of non-film grain characteristics in digital photography (canvas-like) at very high ISOs tend to lend images subtle painterly look. Captures in low light or using low-key lighting, natural or otherwise, promote this feeling.
Strong colour at those ISOs can be essential for high ISO imaging and maintain it is more important that amount of the noise itself. We can now get to higher ISO values without losing this important element. Desaturation can also work on occasion if we are to divert from classic colour. One of the aspects of ‘suitable NR’ is suppressing unwanted colour noise and artefacts. The best software to handle this step I have found is Capture NX-D on NEF file. For minor re-adjustments, Topaz DeNoise works also well. It is my main tool for luminance noise reduction/adjustment. We can remind that ISO setting is only a rough and partial indicator of conditions during the exposure and can be deceiving about how the particular ISO value in question relates to noise levels; just as the absolute time of exposure can be when looking at the output light levels in the photo. There are other factors, other than the value of the ISO, that are determining noise characteristic of a particular sensor/camera (such as light wavelength).
The industry had always had a tendency to prioritise resolution over other picture qualities at high ISOs. I suppose it’s because the technical aspect and spirit in fierce competition outweighed the photographic one. There are signs of improvement though, and the sensor/camera manufacturers are becoming more aware of the importance of the key qualities. For image quality at high ISO, we still need to get about double the progress we got in resolution (much of it thanks to new generation lenses) before reaching possibilities of quality imaging for wide-range use and real needs (which will also find a positive response in the broader consumer world). Not to mention the fact known to many photographers that the resolution, especially for these modest amounts, unlike the IQ, is easily adjustable via the state-of-the-art resizing applications available today (like ON1 Genuine Fractals).