For the LAST TIME...raise your right hand and repeat:
in [Digital Cameras]
|
From: John Sheehy on 28 Dec 2009 17:41 Rich <none(a)nowhere.com> wrote in news:6pWdnW5PHdl826jWnZ2dnUVZ_jdi4p2d(a)giganews.com: > John Sheehy <JPS(a)no.komm> wrote in > news:Xns9CE8B493E8E58jpsnokomm(a)216.168.3.70: >> So, I would say there is some value in showing small images - *IF* it >> actually means something. > > The bird shot looks pretty good. There can be some value in showing > any image, at any size. But, not to illustrate noise control or > resolution. If I were to simply take that shot at face value, I'd > say, yes, it looks like 6400 ISO on a D300. But that would be at > 100%. Uh, no. This is so far from reality; I don't know what to say. The D300 is very good at base ISO; there it has more DR and less patterned deep shadows than any Canon at the pixel level, but the read noise is almost proportional to ISO and grows very quickly as ISO is raised. By 6400 it is well behind any recent Canon. If you're used to looking at conversions from Nikons, they have traditionally removed all high- frequency chroma in the shadows, and virtually removed all color in the deepest shadows. Nikons have just as much chroma noise relative to luminance noise as any other camera using a CFA; luminance and chroma noise are virtually inseparable, as they have the same source. They tend to differ only when one camera has pale CFAs relative to another, then conversion boosts chroma noise. The D300 and 7D seem to have nearly the same RAW color space, though. I don't see any noticeable color response difference between them. I just did an unbiased "conversion" of the Imaging-Resource 6400 versions of the table with the crayons and black mug for both the D300s and the 7D, and while the D300s does quite well, without any visible pattern noise, its noise is more intense and coarser- looking at the pixel level. When you scale the images to the same image size, the difference becomes greater. The D300s is a bit duller-edged, and clearly noisier, including chroma noise. This image you have of Nikons having extremely low chroma noise is an illusion created by the default style of NR for Nikons. > Knowing that is a reduced-size crop, I have no way of actually > understanding how noise looks in the camera for comparative purposes. > I'd literally need another shot, taking at the same exposure levels > with a camera I did know in order to determine what the Canon's actual > noise levels were. That's not possible. The closest you will get is to downsample the IR samples, in the RAW color space. |