The size of the diffraction is related to both diaphragm size and distance between diaphragm and image plane. But if the aperture blades don't move back as the back of the lens, then this point is moot. Further, it's hard to predict how the diffraction will be, with glass element behind aperture blade.
I guess. But we do see some correlation between onset of diffraction limit and pixel density.
Yes.
I have no doubt about this.
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I understand what you're saying. A lot people get confused in these discussions b/c people aren't careful in their wording.
I see your point, smaller sensor, shorter focal length lens, smaller physical aperture, diffraction limiting becomes apparent at larger apperrtures. Thats the reason I don't think all those coolpix cameras stop down much below f8; certainly my Panasonic DMC-LC5 which has a 7-21mm f2 zoom and a 1/1.76" sensor will not stop down below f8.
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Yup. I also wonder if perhaps Nikon considered this when specing their AA filter for this sensor. Perhaps a less aggressive AA filter makes more sense considering the greater likelihood of resolution being limited by the lens quality or a higher f-number.
Be careful. Bjorn did not defined l what he means when he says critically sharp. If he is printing an 8x10, then I have little reason to doubt he could make a critically shapr print from an image shot at f/32. Nor did he compare sharpness to the same situation with a smaller f-number. I somehow doubt that fundamental laws of diffraction are ready to be tossed aside. We may, however, find our practical experience with diffraction effects when using digital sensors to not translate directly to what we saw with film. It would be interesting to see the MTF response of a digital sensor compared to that of some typical films.
Perhaps eventually, cameras will be tested based on performance in resolved lines. Phil does that to a fair extent now.
OK. Here's my bet. The Nikon D2x will test out to have a resolution of 72 lp/mm. This will equate to about 2200 LPH (horizontally) in Phil's review. Based on past experiences, this should be accurate to within about + or - 5% (I know of one result that fell outside this range). I would be very surprised if the actual tested resolution exceeded 2300 or dropped below 2100. Time will tell.
An unexplained tangental remark about diffraction supports what? It certainly does not make any case that the realtionship between aperture and diffration have become unclear. Besides, there never was a "nice clear" relationship to begin with. The quality of the optics involved has always been a complicating factor.
Right. Though that number is probably about right.
Its nice to list all the potential variables, but we should also remember that the various sensor and camera makers have not demonstrated that they have any huge edge in any of these areas. So it is very likely that we will get very predictable results.
Yes, it would appear that Nikon is nearing the limit of the APS sized sensor with the D2X. Since the smaller sensor has greater depth of field, one doesn't have to stop down as much but noise is still a problem.
Not really. I'm not at all sure there is any fundamental agreement on what a reasonable limite would be. If a person is OK with taking a most of their images at relatively larger apertures, there is plenty of room for more pixel density. Especially if the images are generally taken in good light which means that they can use a lower ISO and avoid the noise with tends to appear with smaller sensor sites. And if you choose to stop down for increased DOF you simply lose some resolution that you wouldn't otherwise have anyway with a lower resolution sensor.
