ISO

  • Future DSLR CMOS Improvements

    Digital cameras have been steadily improving for many years now, but recently progress has started to stagnate. One area I am particularly interested in is the low light (high ISO) performance of digital SLRs. There is enough light captured at high ISOs to generate decent images, but the main problem comes in the form of noise. While advances are still being made, the pace of change seems to be lowing. This is evidenced by the difference in capabilities between successive generations of cameras.

    The Canon EOS 5D was a pretty ground-breaking camera when it was launched back in 2005. It was the first ‘affordable’ full frame DSLR, with a 12 megapixel sensor and was capable of shooting at up to 3200 ISO. In reality (as is always the case, even today), only images a stop or two below the max ISO were really usable. 3 years later a massive upgrade came in the form of the 5D mkII, improving low light shooting by a stop, allowing the same quality of shots with half the light. In 2012 the 5D mkIII added another half stop. Now, in 2016, the law of diminishing returns continues with the 5D mkIV showing virtually no improvement in low light performance over the mkIII. Below are what I consider to be the main areas of current tech where there is room for improvement and by how much.

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  • High ISO Shooting

    You often want to capture the best images you can with the light you have available. Most of the time a tripod isn’t practical, and even when it is, a long exposure can be undesirable. When there isn’t much light, setting a high ISO allows for fast shutter speeds in low light, but with increased image noise and less detail in the highlights and shadows. Remember the golden rule for eliminating camera shake:

    Shutter speed must equal double lens focal length (mm) as a fraction of a second
    This means that with a 50mm lens, you’ll need a shutter speed of 1/100sec or faster. Image stabilising lenses help things a lot, but just remember this rule and you’ll be fine.

     

    Why not simply use a high ISO all the time?

    If a fast shutter speed eliminates camera shake, and a high ISO allows for a fast shutter speed, why not simply always shoot at a high ISO? Well, there are two main reasons, the most visible of which is loss of detail. When working out how much perceived detail is lost at high ISOs, I find it helpful to think of my usable image size halving each stop from 3200 upwards, at least when shooting jpegs. A bit more detail can be recovered from RAW files. read more