More megapixels, better photos: Fact or fiction?

Started Feb 7, 2008 | Discussions thread
Jay Turberville Forum Pro • Posts: 12,917
Re: Well Chato ... here is a good comparison...

Also, once the sensor clearly outresolves the lens, you can drop the
use of the AA filter, improving overall sharpness a bit - which is
probably the last little bonus you get for having more pixels.
People seem to forget that putting a filter to purposely blur the
image projected by a lens is a significant compromise.

It is only a compromise in a narrow band of MTFs though.

Sure, but that's the area what often really makes an image look sharp or not. In fact, I suspect that it is the softening of the image right as we reach the finest details that get recorded that makes sharpening so important. And because most sharpening is geared toward enhancing this range of spatial frequencies, the pixel based noise tends to get exaggerated by sharpening. I'd expect an image made by an oversampling sensor would have less need for sharpening.

It is
needed if the optics are sharp, relative to the pixel pitch, and it
is irrelevant in the OOF Bokeh.


I haven't worked out a proof, and
don't know if this is already accepted, but it seems to me that the
dispersions caused by things like AA filters, diffraction, soft
optics, etc, all add in quadrature, just like noise does. Therefore,
an AA filter does the most damage when the PSF is the same as that of
the other optical dispersions. Of course, in some images this can be
a prominent range.

Either way, I see the AA filter as taking the edge off of a sharp lens. Doing so may be a very reasonable compromise given a certain level of sensor and image processing technology. But I think oversampling is probably ultimately a better way. As I recall, it didn't take long for the makers of audio gear to come to that conclusion with sound.

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