noise

[manuel_odabashian]

<p> When adjusting contrast/brightness i understand that noise is always produced. Is there a way of removing it afterwards?</p>

[franklin_white]

<p>If you expose RAW files to be slightly <em>over</em>exposed (without totally blowing a particular color channel beyond recovery), you can often adjust both the brightness and contrast in the RAW editor without adding noise. This technique is preferable to increasing exposure in PP, which always adds noise. If you added noise, most RAW editors include a noise reduction function that will allow you to remove it (while slightly softening the image).</p>

[digitaldog]

<p>http://www.digitalphotopro.com/technique/camera-technique/exposing-for-raw.html</p>

[williamchuttonjr]

<p>Ater data is recorded noise can not be produced or eliminated. The noise is intrinsic to the data. Another way to say this is: the signal-to-noise ratio, SNR, of a digital image depends on how the image was recorded. Nothing can change the inherent SNR afterwords.<br>

Regions of an image with lower SNRs will display more of the noise than regions with higher SNRs when the gain (exposure) or contrast is increased.<br>

As Franklin White wrote above, noise can not be removed. Noise removal programs are actually noise filtering programs. Whenever data is filtered, there is a reduction in information content. The noisy pixels are averaged with nearby less-noisy pixels which improves the noisy pixels at the expense of the less-noisy ones.<br>

Often the information loss not important and careful noise filtering produces a significant aesthetic enhancement. <br>

Some RAW editors let you apply noise filtering selectively. Shadow areas can be selectively filtered and brighter areas with higher SNRs are not affected.</p>

[manuel_odabashian]

<p>so the idea then to do adjustments in camera raw is misleading? What about the idea of smart objects? is all this just hype?</p>

[Tim_Lookingbill]

Why don't you print the image in question at the desired size and see if noise really distracts from what you as the photographer wanted to communicate which is what you really should be concentrating on.

<p>

I can tell you I don't really give much attention to noise during processing of my Raw files. I have some level of noise no matter how well the exposure. I've shot quite a few low light night scenes some of stone walls lit by dim street lights at ISO 800 where there's tons of noise all over the image. I apply a little noise reduction and sharpening in Adobe Camera Raw but never get rid of it all. I never can see the noise on my inkjet prints

even from a 3000x2000 pixel image.

[williamchuttonjr]

<p><em>"so the idea then to do adjustments in camera raw is misleading? What about the idea of smart objects? is all this just hype?"</em></p>

<p>It does not matter if adjustments are done in-camera on RAW data. Noise is just the uncertainty in the data. Once the data is collected – in our case sensor site photon counts – the uncertainty not be changed. In-camera RAW adjustments are no different than post-processing adjustments. In both cases the data is filtered to aesthetically improve the image. <br>

I assume by Smart Objects you refer to you mean Smart Objects you mean a special type of layer in PS CS5, Adobes says:<br>

<em>"Smart Objects are layers that contain image data from raster or vector images, such as Photoshop or Illustrator files. Smart Objects preserve an image’s source content with all its original characteristics, enabling you to perform nondestructive editing to the layer."</em><br>

Since noise is part of the images original characteristics, I don't see how Smart Objects are any different than any other layer when it comes to noise filtering. </p>