Hot answers tagged iso-noise
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In photography, ISO generally refers to a measure of "Film Speed", which I use including reference to digital sensor sensitivity.
In short, the actual letters ISO are a name for the International Organization for Standardization (not, officially, an acronym -- more information here), and in photography it refers to the ISO 12232:2006 standard and other ...
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Is lower ISO always better?
No!
For a fixed amount of light coming into the camera, lowering the ISO will not result in a reduction of noise. The only way to reduce noise is to combine lowing the ISO with letting in more light by opening the aperture of leaving the shutter open longer.
If the amount of light you can let in is limited (you have hit the ...
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It would be wrong to think that increasing ISO results in no "physical" change in the camera at all. The problem with ISO is that people often call it sensitivity. That is really a misnomer...sensitivity is a fixed attribute of any given sensor, and it cannot be changed.
Sensitivity is really more synonymous with the quantum efficiency of the photodiodes, ...
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Noise is often defined as any deviation from a "pure" signal. The signal is taken to be brightness pattern of the image so any variation in the pixel values that represent the image is noise. These variations arise principally due to:
Shot noise. The random way photons are emitted from a lightsource causes random variations in image brightness. The fewer ...
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Regarding the statement:
Is lower ISO always better?
There seem to be a variety of opinions on this topic, and while they may seem mutually exclusive, I am not certain that is the case. There is no cut and dry "Yes, X ISO setting is always better." I think which is better is very dependent on context...on what it is you are trying to shoot, and what ...
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Cost. Every price raise results in fewer sales.
Size. Cooling has to fit somewhere, those handgrips are already full of batteries...
Weight. There's a reason P&S are popular and not lugging around a brick is one of them =)
Battery Life. Cooling costs energy, lost energy means fewer shots in each battery pack.
Minor Improvement: only shots pushing ...
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ISO is effectively a sensitivity of the sensor, whether it be film or digital. In theory, ISO for a digital camera should be the same as for a film camera.
The ISO on film is determined by the grain size of the chemical. What this will mean is that the resolution will be better with a lower ISO film. Also, because a film grain is all or nothing, this will ...
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Noise originates due to a number of factors, see:
What types of noise can be present in digital photographs?
Increasing the number of megapixels keeping everything else constant (sensor size, technology etc.) will increase noise per pixel, but also has the effect of making the noise finer grained which is less objectionable.
ISO does not by itself ...
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It seems unlikely that a sensor cleaning would increase digital noise. (Not impossible, just unlikely.) It's more likely that you're just noticing the same amount of noise more now than you were before.
If some sort of fluid were used to clean the lens, it's possible that there could be a residue on the sensor. This would cause general or spotty ...
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It totally depends - it's an artistic vision thing, and I don't think anyone but you can really answer it. That said, I've rarely encountered folks who were insufficiently concerned about noise; far, far more often people are more worried than they should be. It might be worth your while to have some third-party critiques of prints you're concerned about. ...
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The last two are really the same thing and works due to the fact that in most cases noise is just as likely to push the value of a pixel up as it is to pull the value down.
Let's say the 'true' value of a given pixel is 100 (out of 255). Take 10 images of the same scene in noisy conditions and you might record the following values:
104, 99, 98, 100, 101, ...
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In general I wouldn't recommend doing anything in camera that is irreversibly "baked" into the image, as such things can always be done better, with more control, and more importantly the option to undo, in post on your PC.
There is another feature called Long Exposure Noise reduction which shoots a black frame (i.e. one in which the shutter is closed) in ...
8
I was a big fan of Noise Ninja for the longest time until I got my hands on Topaz Denoise which produced remarkable results. I used to avoid 1600 ISO or higher for the longest time on my Pentax K20, but not any more.
Here's a sample of ISO 3200 after Topaz Denoise:
Here's the before (the change in colour is not related to noise reduction):
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When you change the ISO value to a higher, you really change the amplification in the chip.
Let's look at one single pixel first.
During exposure the pixel receives a number of photons, which generate (let's say) 100 mV, and the chip's noise gives 10 mV. You have a signal-to-noise ratio of 10:1.
Now, you need to expose half the time, and therefore you ...
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Provided your ISO100 image was not underexposed I wouldn't expect a noticeable reduction in noise (except maybe in the deep shadows) with the 5 1 second ISO1600 images blended together.
In the infamous other thread I demonstrated that a 1/30s ISO100 will contain more noise (lower signal to noise ratio) than a 1/30s ISO1600 image. Same amount if light but ...
7
A hot pixel is actually one or more hot photo sensors. Most camera sensor chips are made up of red, green and blue photo sensors, usually placed in a pattern similar to this:
RGRGRGRGRG
GBGBGBGBGB
RGRGRGRGRG
GBGBGBGBGB
Each of these photo sensors ends up as a pixel in the final image, but as each photo sensor only has information about one color ...
7
The bigger the pixels, the less noise there is. This is a matter of physics. More light gets accumulated in each pixel and so it take more noise to appear significant.
The 600D and 7D have APS-C sensors which are small and have a high megapixels count. This makes their pixels comparatively smaller than the 5D Mark II which has a larger sensor and hence ...
7
Firstly had you lowered the ISO whilst staying at 30s f/4 you wouldn't have ended up with any less noise.
There's probably nothing you could have done to prevent the noise, I presume f/4.0 was the maximum aperture and if you went any longer than 30 seconds you would get star trails. You might even get less noise if you raise the ISO but that's another ...
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As with many such things, which is best has some level of opinion and which looks best to an individual. I think Noise Ninja products consistently produce some of the best results. Prior to Lightroom I used it within Bibble, and found it to be simply mouth dropping good.
However, I have found Lightroom 3 to have nearly as good results, bringing it, to me, ...
6
The pro's are self-evident:
Lower noise on high-iso
The biggest con:
Loss of detail
The high-iso noise reduction might remove detail mistakenly. While newer camera algorithms have gotten better at it, it's still not fool proof.
The settings between Off, Low, Normal and High dictate the amount of tolerance used for the setting, which affects the ...
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This question is probably best answered in two parts.
Part1:
You may need to increase the ISO to combat noise. This sounds counter
intuitive due to common misconceptions regarding noise.
Noise is principally caused by lack of light. Lightsources emit photons randomly, the more photons you collect, the more the randomness averages out, leaving a smooth ...
6
I think you might be confusing a few issues here. The terms "Base ISO" or "native ISO" are often used to refer to the unamplified sensitivity of the camera.
In addition to this digital camera sensors have built in amplifiers to amplify a weak signal (such as you get in low light) before it is digitised in order to reduce read noise and increase signal to ...
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The thing that creates noise is not enough light.
You can think of your image has having a constant amount of noise (this is a big inaccurate over simplification, but it helps understand the issue), when you are photographing something nice and bright the sensor captures a lot of data and it completely overpowers the noise.
On the other hand if you are ...
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Like many in-camera features, this boils down to how much do you trust your camera manufacturer vs. how much do you think you can do better yourself by doing it manually in post-production.
As others have noted, once you do something in-camera, you often can't undo it in post. With noise reduction, you'll be losing image detail just like you would when ...
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I was led here by a link in a more recent, similar question, but I can't let the wavelet-based (Noise Ninja, Nik Dfine, Imagenomic Noiseware, Lightroom's own NR) answer stand alone without competition. Another product worth looking at is Topaz Labs' DeNoise (currently in version 5), which is not wavelet-based and can remove a lot of noise while retaining a ...
5
There are many different sources of noise in images with different distributions. For example shot noise, which is a large contributor in low light arises from the random emission of photons follows the poisson distribution. Dark current noise and read noise (major contributions in shadow noise in good light) are more complex as they exhibit banding and are ...
5
Depending on how you cleaned your sensor, you can actually set up semi-permanent static charges in the sensor's layers. This is well known by all who have taken apart web-cams to remove the IR filter. Immediately after their sensors are full of noise. But ... over a week's period of time, these static-charges will dissipate (usually). These induced static ...
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Most likely because it would be bulky, and have a very high energy consumption.
Most cooling for electronics is for bringing it down closer to room temperature, but that wouldn't do much for a camera sensor, as it is mostly used for fractions of a second, so it won't heat up much. You would need a cooling element to get the temperature down, so it would ...
5
It boils down to power, and lack of market demand.
There are specialty cooled-sensor cameras out there. They're generally just used for astrophotography.
The cooler that is used in almost all cooled cameras is what is called a thermoelectric cooler, commonly colloquially called a "Peltier" or "Seebeck cooler".
Generally, you will need a fairly chunky ...
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It sounds like you are underexposing. Noise is generally a more significant problem when the brightest pixels in your image are only about 18% gray level. If this is the case on a consistent basis, especially if you are encountering blurring (I assume due to camera shake) then you are plain and simply using too low of an ISO setting.
If you use a low ISO ...
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