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32

I do expect work has been done on noise perception to build perceptual models to compress images and compare image quality. However, I am unaware of any studies that compare photographer vs non-photographer perception of noise in digital images. I also did not see any in the first several pages of results of a Google Scholar search. only photographers ...


28

This data was iffy then — not really enough data points, and the trendline is dubious: Source: a very timely xkcd That said, the company DxOMark does measurements of camera sensors all the time, designed to be resolution-neutral. Here's a chart of the "Sports" score, which is based on SNR, from all tested APS-C camera models from 2002 to 2018: Given the ...


17

Based on my informal study of my customer preferences and anecdotal evidences, I found that some laypersons do notice noise. 'Noise' is not a familiar term to most non-photographers but I heard my customers say words like, 'dots', 'roughness', 'pixellation' etc. Those who noticed it disliked it and told me that they hoped that I will ensure that the the ...


14

I don't think you'll find that this topic has been studied to the degree that you're looking. You may have some luck in finding a study on perception based on some tangible knowledge or background - but what exactly that background/perception mix is...well, who knows? My wife is in school for her PsyD and has access to more reports than I could ever hope ...


11

Many non-photographers will appreciate a sharp, lifelike image, with a high degree of detail visible. Non-photographers may not always be able to distinguish all the different reasons why a photograph lacks detail (e.g. poor focus or limited depth of field, or camera shake, or lens distortion, or noise, or over-saturation, or limited pixel count). However, ...


9

Beauty is in the eyes of the beholder. It used to be popular to shoot Kodak Royal Pan X film rated at 'ASA' 1200 (That was fast back in the day.) and "soup" it in Dektol (Kodak D-72 paper developer) to get "popcorn" sized grain with practically no enlargement. The noisy grain-pattern was what we were after as aesthetic expression. We'd try the same thing ...


5

This is a known issue with the Nikon 18-200 ƒ/3.5–5.6 VR lens. Some people have reported a simple workaround, some others report the workaround doesn't work. The Problem Apparently the VR mechanism inside the lens emits some infrared radiation, enough that it can be picked up in some cases, especially in long-exposure photography. Although, 30 seconds at ...


5

No, this is not a problem. I see red noise. I see green noise. I see blue noise. That's not a surprise because there are three main colors in the Bayer filter, and the pixels beneath all of those three main colors are noisy. The red and green noise are however more prominent, because the image is blue. This noise is called chroma (chrominance) noise, as ...


4

I think what matters is not who is looking at the picture, but what the picture is about. If we are talking about photojournalism, or about a photo of a special instant - something hard to shoot - then noise is not going to be important. That doesn't mean that it is not going to be noticed, everyone can see the grains. It's just that the subject is so strong ...


3

Even when the sky appears uniform to our eyes, it isn't. The index of refraction of air is affected by a number of things (e.g. the shimmering mirages you see over a hot road) - temperature, humidity, turbulence, pollution, density due to elevation, and probably others - especially at boundaries where one or more of these change rapidly. In addition, just ...


3

Turning my comment into an answer. For comparison's sake, here's some Canon 20D test shots at ISO3200 from back in 2008 (https://kenrockwell.com/tech/dslr-comparison/us.htm#3200). I bring this up to make the point that noise is relative to your goal and expectations. Back then, I had no issues printing up to 5x7 using ISO3200 and that was FAR from the ...


3

Canon has been doing this with the +1/3 and -1/3 stop ISO settings since at least the original 5D back in late 2005. The last EOS DSLR that did not appear to do it was the APS-H EOS 1D Mark IIN introduced in mid-2005. The next 1-series cameras, the APS-H EOS 1D Mark III as well as the FF EOS 1Ds Mark III that were introduced in 2007 both demonstrated this as ...


3

Film speed In analog photography, ISO measures the sensitivity of the film to the light. A film with higher speed will reach its saturation (or overexposure) point faster. You can use a low-ISO film in bright light. In dimmer situations, it may require a wider aperture than you have available or a very long shutter speed. You can use a high-ISO film when ...


3

Many of darktable's algorithms are significantly different from those typically used by other image processing programs. If you cannot get the results you want from darktable, consider trying other raw processing software, such as RawTherapee or UFRaw. The images are consistent with the use of noise reduction filters with different "strengths", where the ...


2

Most noise is not caused by variance in the photon count. On an area as large as a sensor pixel (many times larger an a grain of high speed film) it makes very little difference. Instead it is literal signal noise within the electronics themselves which is then amplified along with the signal as the ISO is increased. The algorithm you're describing is more ...


2

Is there a way to use B&W conversion to reduce noise? That depends on what you mean by 'noise'. The conversion to B&W will effectively eliminate all chrominance noise. It won't do much for luminance noise. You must keep in mind that even though the values reported by each photosite (a/k/a pixel well, sensel, etc.) on a digital sensor are ...


2

So it seems I probably have the solution for this issue I was facing. When I made the sample pictures I was shooting in Manual mode with Active D-Lighting turned to Automatic. This meant that whenever the camera detected a high-contrast scenery it tried to use Active D-Lighting to compensate in the shadowy / dark parts of the picture. Turning this feature ...


2

My guess is you're using denoise (profiled). If so, then you should read darktable's manual section on profiled denoise, where it is clearly stated that you should use a blend mode to avoid that effect you've shown in your examples that look smeared and painterly. To summarize: Use non-local means for luma noise, combined with blend mode ligthness or HSV ...


2

It seems that, in general, most camera makers have been content to trade most, but not quite all, of the gains they've made in terms of sensor efficiency in exchange for more megapixels with roughly the same overall performance with regard to signal-to-noise ratio as their older, lower resolution sensors had. There are some notable exceptions in terms of ...


2

The answer is "C", something entirely different. The signal-to-noise ratio used in imaging is the ratio of the mean signal value divided by the standard deviation of the signal. This is used because photon counts, luminous intensity, etc., are always-positive values that are basically probability distributions. Regarding dB (decibel) scale, imaging uses ...


2

I get pretty good results with an APS-C Canon EOS 7D Mark II inside high school gyms and on high school football fields at night. I own two FF cameras as well and use them for wider angle lenses, yet my choice for the 70-200/2.8 is almost always the 7D2. Canon EOS 7D Mark II + EF 70-200mm f/2.8 L IS II, 200mm, ISO 3200, f/2.8, 1/800. This was one of the ...


2

Your screenshots show ~300% magnification. For comparison, I have a 24" 1920x1200px (so ~94 ppi) monitor and viewing your picture at 30% zoom (which would roughly be the size at 300dpi), it just fills my monitor from top to bottom! What you are doing is known as pixel-peeping - and 300% is an extreme version of that. While it is not inherently bad to pixel-...


2

While most of your questions are already answered by Michael or the question he linked to here are my two cents about your following question: Can someone tell me if I interpret the chart correctly, and if ISO 160, later darkened in post, will really give me cleaner, less noisy images in the end than using ISO 50 (assuming that would be the perfect ...


1

The classical solution for edge-preserving noise reduction is to apply a bilateral filter: https://en.wikipedia.org/wiki/Bilateral_filter . This calculates the average of a group of pixels in the immediate environment, but it ignores the pixels whose difference is too large, like on the other side of an edge. Thus it filters away the differences that are ...


1

The most likely reason is LED event lighting (DMX cans, video projectors etc.) using fast and complicated modulation patterns for dimming or color choice. These units will not actually dim the light, instead switching it on an off at an extreme speed. Classic light dimmers work in a similar way, but incandescent lighting is too slow to follow the switching ...


1

In my opinion this can be some normal background noise generated by the sensor, amplified by Your post-processing. I found a similar pattern at high magnification on pictures taken with Olympus E-510 with noise filtering turned off. Here You have the E-510 noise (white sheet of paper out of focus, picture mode "vivid", ISO 100, low sharpening, noise filter ...


1

The sensor used in Your Canon EOS Rebel SL2/200D is basically the same sensor used in the EOS 80D, the EOS Rebel T7i/800D, EOS-M M6, EOS-M M100, and 77D. It's Canon's current off-the-shelf APS-C sensor. Some of Canon's lower end APS-C models use older sensors that were used in previous versions of the higher level APS-C models, such as the EOS Rebel T6/1300D ...


1

Before you can understand what RawDigger is showing, you need to understand a few basics. Most camera sensors are actually colorblind — they only detect light intensity, not the color of light. In order to record color information, individual pixels are filtered to be more sensitive to hues in the red, green, or blue wavelength regions, thus making each ...


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