Originally posted by slip
a lens that used to be sharp on my K5iis has a slight blur on the K3 due to being able to zoom into the details closer with the higher resolution. I would think that the K1 will be brutal for focusing errors. thoughts?
Randy, I underlined the part ^ that you should think again about. Think about this analogy: a very sharp knife edge that still looks very sharp when viewed with a magnifying glass - but when viewed with a microscope, begins to look like a crumbling, dull wall. Did the knife somehow become less sharp between viewings?
In reality, your lenses will never perform 'worse' with more resolution - they can't. But more resolution allows you to 'magnify' more, which shows you things at 100% you couldn't see before - not because the lens was resolving better at less MP, but because the image just wasn't as magnified. What changed was your absolute value for "100%". This doesn't mean the image looks any better at less resolution, and even if you see flaws more because you're magnifying more, you'll also, sometimes at the same time, see more detail as well.
Every lens, except the truly bad ones, resolve better (MTF) as your MP increases. At some MP point, the curve flattens out and you don't see much of an improvement at typical display sizes, but no lens can ever perform worse with more MP at those display sizes.
In summary: as long as you haven't brushed up against sensor tech limits with read noise and heat, there's almost no IQ-related downside to more MP. The only more-MP downside we really see is with FPS (more data = slower processing,) and file sizes. It's also harder to PP larger files, especially with big batch operations.
Now, sensor manufacturers can reach a current 'sweet spot' where they've maximized DR, or maximized SNR, and that sweet spot may be below the current maximum MP - but it's always a trade off. You sacrifice resolution for perhaps a very small increase in DR on part of ISO the curve, or 1/4 stop less noise on part of the curve, etc... things that may be hard to even notice yet matter to some, but in reality are not keeping the larger-MP bodies from selling the best - for a reason.
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