45

This is a featured called Long Exposure Noise Reduction. To cancel out noise the camera will close the shutter and take an equally long exposure again, this time capturing a black image with only the electrical noise on it. This information is then used to reduce the noise on the original exposure. In the camera settings you can disable the Noise Reduction ...


30

"Expose to the right" means record the brightest image you can and then reduce the brightness in post to achieve the desired level. The word "right" comes from the histogram, where conventionally brightness increases left to right, thus increasing brightness shifts the whole histogram to the right. ETTR helps reduce noise simply by capturing more light, ...


22

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 ...


22

Can I get the same result by coping a raw ( same exposure ) file many times and stacking to reduce noise as I would if I used many separate exposures? No. If you stack copies of the same image, you'll amplify the noise right along with the signal. Stacking images to reduce noise is an averaging process. It's like a science experiment: you don't measure ...


21

While there may be truth to the principle that noise adds the illusion of detail, in this example I think you are misinterpreting what you are looking at. If I remove all the noise in its lower part, it will not look natural (from my point of view) This is mostly because no noise-reduction algorithm can perfectly remove all noise and retain all detail. ...


19

Look up Long Exposure Noise Reduction in your camera's manual. Depending on the model, you may or may not be able to continue taking photos. Some models do the processing immediately after the exposure. Some allow you to continue to take exposures, and then do the processing. This feature uses dark frame subtraction. The idea being that if you expose a ...


18

This looks like the effect of noise reduction at high ISOs. Heavy NR is common in compact cameras with small sensors. Fujifilm cameras of that generation did it very well compared to others of the time, but there's only so much blood you can get from a stone. On most modern high-megapixel point and shoot cameras, you'll see this even at low-ISOs if you ...


14

Well, perhaps you should have gone out after all :) The noise is thermal noise, which will become noticeable as your sensor heats up during a long exposure. In astrophotography, it's quite a common problem. Some ways to reduce such noise: cool sensor down, e.g. by shooting in the cold weather. Note that cold also negatively affects battery life. set the ...


13

You cannot. Removing noise via photo stacking works on the principle that the noise in your images is random, and appears in different places of the image between exposures. When you stack multiple exposures on top of each other, a common method to remove this random noise is called median blending. During this process, software will evaluate the same pixel ...


12

The key difference between the two is that one works on a post-digitized image, where as the other works on the pre-digitized analog signal. Whenever you work with an analog signal, you have the ability to be more precise and accurate, and can eliminate noise before it is "burned into" a digitized image. Thats most certainly not to say that applying noise ...


11

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 ...


11

No Canon dSLR has built in image stabilization. Canon offers it in select lenses, known as 'IS' lenses. So, no, neither offer image stabilization. All Canon cameras also offer noise reduction, and of course, it can be applied (or not in the case of RAW) on the computer after the fact as well. Does it matter? Noise reduction matters, because all cameras ...


11

When I have extremely noisy images, I do two things: Use a 3rd party noise reduction plugin - in my case I use Topaz DeNoise - it, and others, have free trials - so you could give them a try if you want to experiment. These denoise plugins have sliders that will reduce noise, which softens the image, but you also have control over detail (you can decrease ...


11

The technique used by Cortex Camera is called Median Blending. Astrophotographers have been using this concept for years to combine multiple photos of dim objects in the night sky to reduce the noise and increase contrast and color. It is often referred to as image stacking in which hundreds of images of the same piece of sky are overlaid and the values for ...


11

The long exposure Noise Reduction takes a "dark frame" after the real shot, and then uses the noise pattern from that image to reduce the noise generated by the sensor. That's why the exposure takes twice as long as this NR were disabled. Long time exposure can increase the sensor temperature, and increased temperature also means more noise. So you should ...


10

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, ...


10

You can only preview noise reduction in RT when you zoom image to 100%, even in latest version. Many other tools have same limitations for previewing, they are marked with small "1:1" label near their names.


9

In general, the camera's manual will tell you the operating temperatures for the camera. Like all pieces of electronics, excessive heat isn't good for it. That said, I've only seen anecdotal evidence of heat adversely affecting image quality. It seems more common for batteries to stop working. As for noise, you're probably going to have this issue in broad ...


9

There has been an improvement between the 40D and 650D, but not that great. Certainly less than a stop. You'll get a far far greater improvement in image quality by getting more light onto the sensor. There are a number of ways to achieve this: Depending on what lens you're currently using you may be able to get a three stop improvement by switching to a ...


8

Lightroom and Photoshop aren't really (supposed to be) competing products -- they're complementary products that overlap. Lightroom is all about managing your workflow, which just happens to include image processing in most cases. Photoshop, on the other hand, is image processing to the max, but it doesn't really do much to help your workflow. There's ...


8

To be short ETTR is a smart usage of two fact: There is more information in the high light (the right of the level curve) than in the low light (the left of the level curve). This is due to the fact that capter has linear response to the light intensity while human perception is rather log (what you perceive as twice brighter is in fact not twice the amount ...


8

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 ...


8

Noise is random, it causes gray values to fluctuate from one pixel to the next. This is then random information present at the smallest scale in the picture. If you remove it, then it gives the illusion of the image having become less sharp, as the gray values are not changing as fast on the smallest scale anymore. This doesn't mean that removing the noise ...


7

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 ...


7

Simple answer is YES! Noise is an undesirable artifact, and many operations can enhance its appearance, not just sharpening. Tweaking curves, adjusting contrast, working exposure, etc. can all have some impact on the noise that is present in an image...although sharpening tends to have the greatest impact. It is important to handle the bulk of your noise ...


7

It should be done in post-processing. You have absolute control of the noise-reduction parameters at that point and can rethink a setting if it smears your image too much. It's best to shoot in RAW and postpone what decisions you can until you get into Lightroom or Photoshop or [insert tool of choice here].


7

It is poorly written. Indicated Green Background refers to the list below where lenses models with stabilization are highlighted with a green background like the AF-S 16-35mm in the wide-angle section:


7

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 ...


7

Active D-Lighting Active D-Lighting isn't necessary at all. It works by doing two things: slightly underexposing (by 1/3 to 2/3 stop) and applying some adjustments to raise the shadows back up It isn't needed if you shoot RAW as you can underexpose and raise the shadows in post It is only relevant if you are shooting high dynamic range scenes with bright ...


7

This is normal considering the high ISO you are using on that camera. If you look at samples for each ISO with the Canon 7D, yours show more noise than the ISO 1600, similar to the ISO 3200 crop. Notice that I only shot full-stop ISO which is important with Canon DSLRs because the gain to obtain the 1/3 stops in between is applied in software by the ...


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