Sensor size matters

Started Feb 15, 2012 | Discussions thread
photoPhlow Regular Member • Posts: 111
Re: Sensor size matters

There is a good point in the comments section:

David says:

"While I enjoyed much of this article, the discussion of pixel size and noise (high ISO performance) is confused and perpetuates the myth that more megapixels equals more noise. Yes, smaller pixels have more noise than bigger pixels. And if you are comparing images at the pixel level , then the lower megapixel sensor will generally outperform the higher megapixel sensor. But except for the pixel peepers, we tend not to look at images at the pixel level. We tend to downsample them and view them online, or print them. And in that case, all other things being equal, there is no noise disadvantage to having more megapixels. Indeed, a higher megapixel camera collects more information than a lower megapixel camera, which can then be used to average out the noise.

DxOMark recognises this, and when making their ISO comparisons they essentially downsample all images to 8 Mpx."

The article is written more from an engineering perspective rather than a photography perspective.

Per-pixel noise is determined mostly by pixel size. However, perceived noise at any particular print size has nothing to do with per-pixel noise. It either gets averaged out by our visual perception system, some NR software, or by the downsampling needed to make the print.

I am a pixel-peeper myself. There is a point beyond which too many pixels is a pain, as the noise requires more post-processing to the pixel-peeper ... but they don't have any downside at a fixed-dpi print or a fixed-size JPEG. However, more pixels always have the possibility, under good lighting and operation, to give greater image detail.

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