When the 36 megapixel Nikon d800 was announced, a few of the experts said that the huge hike in megapixels would show up the limitations of your favourite lenses.
That seemed a logical consequence to me, I have to admit, but Ctein, the pixel-level guru at The Online Photographer (TOP) has a different point of view. He shares it here:
http://theonlinephotographer.typepad.com/the_online_photographer/2012/02/d800-megapixels.html
In that post, he addresses a handful of myths, and here’s what he says about
Myth #4
‘It's pointless to add more pixels [to sensors] because lenses aren't good enough
Reality: I have no idea where this one came from, because it's contradicted by decades of lens and camera test data. I'm going to cut through the morass of minutia-based arguments about pixel dimensions, filter geometries, and Airy disks and lay it out in very simple terms. A 16-megapixel 35mm-sized Bayer array sensor is going to resolve around 50 line pairs per millimeter (lp/mm). A 36-megapixel sensor will resolve around 75 lp/mm. Even mediocre 35mm lenses will hit 75 lp/mm at some aperture over some portion of their field of view. This is true of both fixed focal length and zoom lenses.
Decent (not at all exceptional) 35mm-format lenses can hit 75 lp/mm at just about all apertures and will do so over most of the field of view for at least one aperture. They'll show peak resolutions more like twice that. Really good lenses (not necessarily expensive ones) will be able to exceed 75 line pair per millimeter without even trying hard over most/all of the field of view and will have peak resolutions three or more times that.
Furthermore, until the lens resolution drops to only half that of the sensor, improving sensor resolution will produce an observable improvement in image resolution.
See the previously cited diffraction column and "Why 80 Megapixels Just Won't Be Enough..."
The only thing holding back camera makers from 50mp, 60mp or more on FX is the data-processing involved. A 72mp FX sensor would only be able to do about 1 frame per second, which most people would think is too slow. And, the high-ISO wouldn't be so hot. But hey, maybe they'll do a D800L for the landscape guys. We have to wait for the data processing to catch up. I think Nikon's best glass -- the recent f/1.4 primes -- are fully capable of delivering with a 72mp sensor, at least in the center of the frame.’
There you go!
Kim
Comments