Nikon D4s: Bayer processing breakthru?

Started 4 months ago | Discussions thread
Scottelly
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Re: Maybe, but I don't think so.....
In reply to DMillier, 4 months ago

DMillier wrote:

A very thorough review - you do a better job than the professionals!

Some points to reflect upon:

- there is no reason to think that full frame increases the resolution over APS-C if the pixel counts are the same. More dynamic range maybe, lower noise at high ISOs for sure, ability to distinguish more subtle shades of colour in many cases, yes. But no reason resolution should be any different as that is limited by pixel count. You do see differences in lenses in the sense that APS-C is more demanding on a lens's resolution while full frame is more demanding of the lens edge/corner performance.

- You shouldn't expect removal of the AA filter will necessarily lead to an increase in resolution. It might when compared to a camera with an overly strong AA filter but in general what the AA filter does is reduce the micro-contrast/acutance around the Nyquist frequency rather than wiping out the detail completely.

- there is no reason to think that the resolution performance of any of Nikon's 24MP cameras should be that much different whether full frame or half frame, cheap or expensive, fitted with an AA filter or not. They should all resolve in the same ball park.

- The Merrill sensor certainly has high resolution but where it shines is in micro-contrast/acutance as that allows you to see the resolution it has more easily. The eye is fooled by micro-contrast and we will often rate a lower resolution image as preferable if it has high contrast. The other thing with foveon is you can never ignore luminance aliasing. It's there all the time (right off the scale on Techradar's chart) and it is often difficult to distinguish real detail from false detail. Different people will arrive at a different value on the chart depending on their tolerance of aliasing.

But overall, I think you have pointed out so many inconsistencies in their scores that I would be sceptical at any conclusions they arrive at for any camera!

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"...while I am tempted to bludgeon you, I would rather have you come away with an improved understanding of how these sensors work" ---- Eric Fossum
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When you mention micro-contrast, I'm pretty sure you're talking about stuff like this, right?

Screen capture from DPreview's image comparison tool (with view zoom reset).

In this particular instance the Sigma SD1 trumps all others . . . even the 40 MP medium format 645D from Pentax. This is where the Foveon sensor is strongest.

When you write that it does not matter whether a sensor is full-frame or APS-C, I must argue that I believe you are mistaken. Lens resolution is limited, and we are seeing serious resolution problems today, because of the limitations of the lenses. The old 50mm Sigma is good . . . but it's not so good that you can discount the lens resolution (even in the center of the image). If a lens can resolve 50 lp/mm across the frame, when the aperture is set two stops smaller than maximum, with a little better resolution at the center of the frame, then it is considered a reasonable quality lens, similar to the Sigma 50mm that TechRadar used in their tests. Such a lens is capable of resolving 1,200 line pairs for the entire height of the image, which would require at least twice the number of pixels (2,400). A sensor that has no AA filter and resolves 6,000 pixels across and 4,000 pixels high can easily resolve more than 2,400 line pairs high. There is the issue. We are reaching the resolution limits of the lenses we are using, as the following charts taken from the review of the Sigma lens here on DPreview, show us.

The above image shows how low the resolution appears to be, when the Sigma 50mm f1.4 EX is used on an APS-C sensor, when contrasted against the resolution when measured with a larger, full-frame sensor, which was used for the results shown in the image below. (In the graph produced from the full-frame sensor, the resolution appears to go off the chart, near the middle of the frame.)

If you don't agree with what I am saying here Lin, please point me to some information that shows me that lens resolution is not a major factor in testing with current lenses. (I realize that the new 50mm A may be an exception, but that is not the lens they used in the tests. I believe that new Art series lens may indeed become a standard that many testers will use in the future, but some day we are likely to find that even that lens has become a limitation, when testing some of the newest APS-C sensor cameras in the year 2017 or 2018.)

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