Is upsizing/zooming more effective when using "simple" ratios?
Over at answers.microsoft.com people are wondering why certain zooms are more blurry than others, even though the clearer ones are often more heavily zoomed. For instance, a 70% zoom can be more blurred than a 90% zoom of the same picture.
Depends on the algorithm. ImageMagick defaults to Lanczos3 for downsampling, and a different one (forgot the name) for upsampling.
My theory is that zooming/resampling is best done in fixed increments. So a 50% zoom will always look better than a 49% zoom.
This would be true of Bilinear downsampling, but hardly at all with Lanczos. However 50% and 49% are not upsizing as in your subject line.
But many hours of research has yielded nothing concrete. Before I suggest to Microsoft that they abandon their 10% zoom increments I want to know if I'm right that they're not optimal.
That was common about a decade ago, before Photoshop came up with Bicubic Smoother.
To clarify, the product is Microsoft's Photos and I imagine that will draw a few giggles. We're working to make it a respectable photo app, yet aimed at the masses.
Anyone? I don't use this product and have no interest in it.
The problem is that some of the user community is trying to understand the inconsistencies of zooming. Apparently this isn't a problem with most editors but I'd assumed that Microsoft was using fairly standard techniques (although naturally the most basic of them).
If the 50% vs 49% is obvious to you, I'd bet they are using Bilinear resampling.
I'm sure a 50% zoom must be better than a 49% zoom but to what degree? You'd probably need a magnifying glass.
Oh, you can't see it?
So are techniques now so sophisticated that there's no need to worry about simplifying things for the software? If so, was this a problem in the past? I know MS won't change its zooming algorithms but it might zoom in "basic" intervals if we can make a good case for it.
Yes - there is better software out there. If you are interested, much more info here:
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