D300 versus 20D continued analysis

Started Dec 5, 2007 | Discussions thread
abortz Junior Member • Posts: 43
Re: D300 versus 20D continued analysis

I really don't understand why this is such a hard concept for everyone to understand: by comparing 1:1 crops from cameras with different megapixel size sensors, you are doing the equivalent of printing the image from the sensor with more pixels at a larger size, then comparing the two at the same viewing distance. This is because your monitor has a fixed pixel density while you are viewing both images!

Obviously, to compare apples to apples, we'd like to compare both images as if they were printed to the same size and viewed from the same distance (or, for an even better comparison given the constraints of printing technology, printed at the same dpi but then positioned so that they appear the same size to the viewer). While down/upsizing one of the images so that they both appear to be the same size on screen is an attempt to mimic this, it is not necessarily a better way to compare images, because of artifacts introduced by interpolation and fractional downsampling and the combination of low pixel density and close viewing distance of computer screens.

Given that there is no really good way to compare images of different dimensions on the common computer monitor, everyone needs to be aware of the biases that are introduced by comparing 1:1 crops from different cameras and by scaling.

  • Andrew

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