I performed the horizontal and vertical filtering operations of the previous post on D810 dark-field images from ISO 100 to ISO 6400 in whole-stop steps. Here’s the result, for horizontal kernels, which preserve vertical features: And for vertical kernels: You’ll notice that the horizontal kernel results are more nearly straight lines in the log-log graphs,… [Read More]
Convolution filtering and read noise
A reader commented on the previous post, and posted this link to a web page where he analyzed the spatial aspects of the read noise on a Sony NEX-6. He contends, with excellent justification, that the construction of the sensor on that camera, and sensors with similar column-parallel ADCs, creates more low-frequency read noise in… [Read More]
In search of a read noise ugliness metric
Beauty is in the mind of the beholder, so ’tis said. I guess ugliness must be as well. Maybe I’m on a fool’s mission, but I’d like to figure out a way to mathematically calculate the visual effect of read noise. If you look at the histogram of dark-field noise for a digital camera, providing… [Read More]
Color space conversion accuracy — summary
Unless something comes up, I’m done with the color space conversion accuracy work. I’ll use this post to summarize what I’ve found over the last couple of weeks and link to the posts with the details. The first conclusion is that, using 16-bit precision, for all colors within the gamut of both the source and… [Read More]
On dynamic range — a guest post
Today we have a guest poster, Jack Hogan. Over on the DPR forum, a question has been asked, and argued endlessly: when faced with a 16-stop intra-scene dynamic range, what’s the dynamic range of an image captured with a 14-bit camera? Jack responded with a little Chautauqua on how a camera works that I thought… [Read More]
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