Saturday, 25 June 2011

Shooting High ISO and noise management

I have never switched my ISO settings so widely or as frequently as I did on my visit to the Turner. As well as using ISO 50 for my 30 second exposures I also went up to ISO 12,800 for the hand held shots to nullify the effects of camera shake. Of course, the big issue with winding up the ISO is that you increase noise too. Whilst modern cameras are far better than those of even a few years ago, at these high settings noise needs to be controlled.

Canon 1D Mk IV, EF 24-105 f/4 IS lens at 24mm, 1/30 second hand-held at f/8, ISO 12,800, +2/3 EV
[Taken in Conrad Shawcross' installation "Projections of a Perfect Third"  - it's pretty dark in there].

Tips for shooting at high ISO:
  1. Think about what shutter speed you can get away with and only increase the ISO as a last resort. If you have image stabilisation/vibration reduction this can really help.
  2. Expose to the right; you want to be clipping the highlights as much as you dare, whilst being able to recover these later during image processing. The noise is always in the shadow areas and by pushing the exposure you will drastically reduce it
  3. For images like the one above where the tonal range is quite narrow you can get very good results. For images with wide tonal and colour ranges you may not be so successful - I find that dark blues are particularly difficult to handle
  4. Shoot RAW. JPEGS will never hold the detail you need to get acceptable images
  5. Of course, your carefully controlled RAW image will still hold some noise and there are umpteen different ways to manage this in software which I won't go into here but following the rules above will give you the best chance of getting it right in camera first and that's more than half the battle
All that said, there are times when you will want to use a high ISO to give that grainy type of texture as a creative effect too, particularly in monochrome.

No comments:

Post a Comment