Raw vs. Jpeg with High ISO

[tara_ratliff]

<p>Does Raw record digital noise more than a Jpeg file? I was opening up some jpegs on a computer at school and was uncertain if the High ISO was not showing the dots because the computer monitor was not great or if because the Raw files show more digital noise than a jpeg file...<br>

There was really no substantial difference between the same picture shot at Iso 100 and Iso 6400 with the jpeg file.<br>

Thank you.</p>

[matttonkin]

<p>Jpegs have noise reduction applied directly in the camera. RAW may or may not have it applied but depending on the program you use to view it the reduction may not be applied. With RAW you can apply noise reduction settings after the fact.</p>

[JosvanEekelen]

In general jpg-s are processed whereby noise is reduced, often with some detail loss. RAW-s are not processed so they

will show the noise. With RAW-s you are free to process them yourself, choosing between noise reduction and detail. And

with the possibility to do further processing. Ha, Matt beat me by 1 minute.

[paddler4]

<p>Matt and Jos are of course right, but I think you might be missing something more fundamental.</p>

<blockquote>

<p>Does Raw record digital noise more than a Jpeg file?</p>

</blockquote>

<p>Your camera does not record a jpeg. The camera records only raw images. These have to be processed, either by the camera or by you, to make them viewable. When you set the camera to jpeg, you are telling the camera to do the processing for you. When you view a "raw" image, it is no longer raw--you are viewing an image that has been processed by the computer.<br>

<br />So any given click of the shutter records the same amount of noise regardless of which setting you use. Whether you see more noise in the processed image depends entirely on how the image has been processed, either by you or by the camera. If you like the level of noise reduction your camera is providing when it converts to jpeg, just apply more NR in your own postprocessing.</p>

[dave_redmann]

<p>I basically agree with what's been said, but here's my take on it: an in-camera JPEG will almost always have more noise reduction applied to it than the corresponding raw file would (although apparently some cameras apply some noise reduction to "raw" files, and some cameras may allow you to turn off all noise reduction even for JPEG's). You can always apply more noise reduction, but once it has been applied and the resulting image data saved as a JPEG, there is no way to unapply it.</p>

<p>Noise reduction does reduce noise, but it also smears / reduces fine details and subtle tonalities. There are different ways to apply noise reduction, some of which may be better than others for any particular picture and/or personal preference. So most experts think they can get better results by working from raw files and then applying the type and the degree of noise reduction that gives the best results for the particular picture (and particular photographer's taste). Noise reduction may be applied at the raw conversion stage, or may be applied later.</p>

<p>When I got my first digital camera more than seven years ago, it surprised me that JPEG's shot at ISO 1600 produced low-noise 8x10-inch prints, but when I took otherwise-identical raw files and started from there, the noise was plainly visible. But now we understand why.</p>

<p>Last but not least, for beginners especially, I have to take issue with the statement, "Your camera does not <em>record</em> a jpeg. The camera records only raw images." (Emphasis added.) Not so. Almost all current digital cameras offer the option of recording JPEG's, often with the related option not to record any other format. And the majority of reasonably-current compact, fixed-lens digital cameras record only JPEG's. No doubt that before any camera records or even creates the data for the JPEG, it has to convert the light hitting each pixel on the sensor to an electrical charge, then convert that analog charge to a corresponding number, and then process (de-mosaic, white-balance, noise-reduce, etc.) those numbers and create JPEG-type information, before it <em>records</em> anything (i.e., writes it to the flash card). So with most compact digitals, all that's ever recorded is a JPEG. (Of course, some compact digitals can record raw files, and for some cameras--notably Canons, with CHDK--there are hacks to give you the option. And pretty much every interchangeable-lens camera offers the option to record raw files.)</p>

[chrisnielsen]

<blockquote>

<p>There was really no substantial difference between the same picture shot at Iso 100 and Iso 6400 with the jpeg file.</p>

</blockquote>

<p> <br>

I don't believe that for a second. You sure it was actually set to 6400?</p>

[keith reeder]

<p>I would have agreed with you unreservedly, Chris - until I saw <strong><a href="http://i50.tinypic.com/2mdm5aq.jpg">this</a></strong>: 10000 (ten thousand - the Exif is in the image) ISO from a 5D Mk III.</p>

<p>I've certainly seen 100 ISO shots this noisy...</p>

<p>(Yes, if you really peek, you'd probably be able to pick this out from a 100 ISO 5D Mk III shot, but a little bit of NR on it and it'd be tough, at this resolution).</p>

[digitaldog]

<p>There was really no substantial difference between the same picture shot at Iso 100 and Iso 6400 with the jpeg file.<br>

Well depending on the camera, an ISO 800 raw can have <strong>less</strong> noise than an ISO 100 raw:<br>

http://digitaldog.net/files/100vs800iso.jpg<br>

The exposure you apply to raw data, which can often produce an awful JPEG plays a role here. That and the raw processing of these exposures which JPEG can't provide. <br>

Bottom line is there is more to noise than just the ISO when you're dealing with raw data. What JPEG, you get what the camera gives you.</p>

[fredscal]

<p>RAWs are raw. The noise is just as the sensor outputs it. Then the viewing software may or may not apply noise reduction (usually not), which you can (usually) adjust manually, depending on the software.</p>

<p>JPEGs are processed in-camera. This process usually includes noise-reduction (that is then non-reversible), as well as a bit of sharpening, but you can disable all that from your camera's menu. (Or make it stronger, for that matter.) </p>

<p>Hope this is clear enough.</p>

[digitaldog]

<p>Raw are indeed raws but the degree of noise is hugely affected by exposure. Exposure that would destroy a JPEG because of the lack of control over rendering for this proper raw exposure.</p>

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

[ellis_vener_photography]

Andrew is correct. For a raw file all processing settings including noise reduction and also color space are more along

the lines of instructions for what you want to happen when you decide to create a TIFF, PSD or JPEG version of that set

of data. An easy way to think about is to think of the raw file and your processing instructions as the two factors in a

simple multiplication equation. The metaphor is not exact of course as you cannot "divide" the resulting "product (TIFF

etc.) by either "factor" to get the other "factor."