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Old Sep 30, 2005, 11:05 AM   #1
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Would someone kindly tell me what shooting in RAW is? I'm trying to imagine some of you guys & gals shooting in RAW, can'tdescribe it in words!

Can I do it with my S2 IS? and if so how? as well as what benefits will I derive from it?

Thanks for your help. It's probably second nature to most of you.

Mack C. in Brooklin ON
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Old Sep 30, 2005, 11:56 AM   #2
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Unfortunately, it looks like the S2 doesn't have RAW capability. RAW is kind of hard to explain. Basically, it allows you to process the picture after you've taken it. Sound confusing?

For example, if you take a picture and are not quite sure about the lighting, which would effect white balance and exposure, then you can open the file up and mostly likely correct it exactly how you should have taken it. When you shoot a JPEG image, the camera processes it, when you shoot RAW, it doesn't.With a JPEG file you are largely committing yourself at the time of exposure to several of the most important aspects of image quality, namely white balance, overall contrast, color saturation and the like. With a raw file you are free to make decisions about these settings at your leisure. Also, RAW can be processed as many times as you want, however you want. You could have one RAW file and get 100 different looking images out of it.

Also, since digital camera's don't have the best exposure latitude/dynamic range, you could process a oneRAW file for the highlights, one for the shadows and combine them together and have an image with excellent highlights AND shadows...a difficult thing to do with consumer digital cameras. RAW is also 16 bit color as opposed to JPEGs 8 bit (yes, twice as much).

A raw file is essentially the data that the camera's chip recorded along with some additional information tagged on. A JPEG file is one that has had the camera apply linear conversion, matrix conversion, white balance, contrast, and saturation, and then has had some level of potentially destructive compression applied.

For the most part, everything is better in RAW, although it takes up a considerable amount more of memory.

I think I did a crummy job describing it for you. Hope it helps some though.
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Old Sep 30, 2005, 12:00 PM   #3
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As far as I'm aware the Cannon S2 IS does not have a RAW option. Most compact digicams store the photos in JPG format. This requires software in the camera to take the RAW data from the sensor and process it. When shooting RAW it is the data taken straight from the sensor that is stored. This generally results in much bigger files than shooting JPG. The big bonus is that as it contains the data just as it came from the sensor it can be processed on the computer using the setting the photographer chooses rather than automatically in camera. The type of thing this allows are adjusting the white balance and adjusting the exposure. It's just a lot more flexible but it does take more time in post processing as all the images have to be processed to get the best out of them.
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Old Sep 30, 2005, 12:46 PM   #4
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Most digital cameras have 12-bit digitizers in them. When you take a picture, you get the moral equivalent of 36 bits of data per RGB pixel (it's a bit more compicated than this -- most digital cameras have more green sensors than red or blue, for example. So the simple idea of 12+12+12 for r+g+b is not quite precise, but close enough for this discussion).

When you want to save the picture that was taken by your camera, you commonly have one of three choices -- JPEG, RAW, or TIFF. There are plusses and minuses to each. What JPEG does isreduce the 12bits per channel of data to 8 bits per channel. It then applies "lossy" compression to the result, in which some of the remaining data is thrown away to achieve smaller file sizes. The intention of the 12-bit to 8-bit convestion is basically to accommodate your display device. Your computer monitor only accepts 8 bits per channel of data, so the image is going to get clipped to that sooner or later. The additional throwing away of data is intended to throw away stuff that you can't see (ususally, the JPEG algorithm guesses right on this, but not always).

TIFF images keep all the 12 bits of data and, as implemented in digital cameras,doesn't use lossy compression. TIFF is a standard file format. Because TIFF is uncompressed (not exactly -- it uses a very inefficient compression called run-length encoding -- RLE --which makes images a little bit smaller but doesn't lose any data), however, it makes big files. On my FZ20, Panasonic estimates that I could store 61 2560x1920 images on a 1-Gig memory card. Be advised that many computer program don't know how to deal with TIFF files that have more than 8 bits per channel of data, so you might have difficulty getting a 12-bits-per-channel TIFF file to be displayed. PhotoShop is one program that can handle this format without any difficulty.

RAW is a proprietary format that varies with each manufacturer. Its goal is to create as small image files as possible without throwing away any of the data that you get in TIFF files. My FZ20 doesn't have a RAW mode. The FZ30 does, and the manual suggests that you can get more than a 60% improvement in storage capacity. On the same 1 Gig card, you could get about 100 RAW images. The highest quality JPEGs would allow about 400 images on the same card.

I presume that RAW takes advantage of the fact that there are fewer R and B channels of data as one of the ways that it gets better compression. It also undoubtedly uses a smarter lossless compression scheme than RLE.

So what is not to like? First, you need to have 12 bits per channel of real data in the image for this to be of use. The FZ30 is getting rather harsh reviews for its high noise content at 8 bits, so the added bits available in RAW format for that camera may not be all that useful. A dSLR will generally be able to provide more bits of good, noise-free data, so RAW makes more sense the better the camera sensor is.

Second, most computer programs can't read RAW data. In the case of the FZ30 right now as I understand it, the only thng that can read it is a Panasonic program that just converts it into an 8-bit-per-channelJPEG once you get it off the camera. So there is no point in the format until some better software comes along. Other digital cameras' RAW formats can be read by smarter software. In some cases, PhotoShop can read the format and make use of the additional data.

So, if you have a full combination of hardware and software that can make use of it, and you are interested in editing your images after you take them, RAW can provide both better image storage efficiency than TIFF and better image dynamic range than JPEG. In any case, once you've edited the image, you'll probably be saving the final image in 8-bit-per-channel JPEG, as it is a format that everything in the computer world knows how to display.


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Old Oct 1, 2005, 6:48 AM   #5
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SlapN., Nag., & tclune;

thanks for your in-depth explanations of shooting RAW! I hope I can retain some ofthe info you each have provided.

Mack C. in Brooklin ON
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Old Oct 1, 2005, 4:25 PM   #6
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I, too, am very highly appreciative for the rendered explanations on this "RAW" issue. I had always wondered what it was, as I had been hearing the mention of it quite frequently. I'm thinking that it is something that I will most definitely want to have featured in my next DC. It has also been stated that there isn't much - in the line of required software (at least at the present time) - available for being able to realise the full benefits of 'RAW'. But, by the time that I am ready for my next digital camera, this may be a whole different story.
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Old Oct 1, 2005, 9:48 PM   #7
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NLAlston wrote:
Quote:
I, too, am very highly appreciative for the rendered explanations on this "RAW" issue. I had always wondered what it was, as I had been hearing the mention of it quite frequently. I'm thinking that it is something that I will most definitely want to have featured in my next DC. It has also been stated that there isn't much - in the line of required software (at least at the present time) - available for being able to realise the full benefits of 'RAW'. But, by the time that I am ready for my next digital camera, this may be a whole different story.
It seems to me you may have misinterpreted some of the comments. The analogy often used is that a JPEG format image is like having a negative from a photograph: you can enlarge it again and again using different papers and print developers, but you're basically limited by the way the negative was developed the first time.

RAW format, on the other hand, is like having an exposed piece of film with a latent image, but that hasn't yet been developed at all. Using your RAW developer you can decide to develop it for hard contrast, low contrast, different color treatments (white balance), etc. Some developers include sharpening and noise-reduction tools as well. The difference is that when you "develop" the image with your RAW developer, you still have the original piece of film untouched (the original RAW datafile), so if you don't like the way one development comes out, you can go back and develop it again and again, using different parameters. You can't do that with JPEG!

Basically, all digital cameras initially take pictures as RAW data. But when you set your camera for JPEG, the camera 's own internal "processing lab" (the JPEG engine) makes a lot of decisions about how the RAW data will be interpreted and processed (some of those decisions are based on camera settings you make, like saturation, contrast, white balance, etc.); the camera develops the image internally and produces a compressed JPEG image--and then it discards the bulky RAW data.

IF you like the way the camera's JPEG engine has processed the image, no sweat. But if you or your camera has screwed up the white balance, for example, it's much more difficult to change the overall color temperature using ordinary Photoshop in post-processing than it is to make a simple White Balance change when doing your RAW processing. And there are many times your desktop computer with all its computing power can do a better job with a dedicated RAW developer than your camera can with its tiny chip. Depending on the camera and RAW algorithms used, shooting RAW may allow you to draw an additional 2 steps of latitude from the image. You can set your camera to ANY white balance setting yet immediately change it in RAW development.

There is no dearth of excellent RAW processors out there, and each person has their favorite. If you want to experiment you can't go wrong by downloading RawShooter Essentials from Pixmantec. It is a beta version of a hoped-for commercial processor to be issused "real soon now" . It is fast and entirely free and it may work fine for your purposes. Then either find some RAW images to download from the net (or borrow some from a friend), and practice processing them with RSE.

HOWEVER, RSE is not perfect, and a number of us have found problems with its color rendition, especially with some cameras' RAW files, notably in my case, those produced by Olympus E-1 and E-300 cameras. My personal favorite is Silkypix, a Japanese RAW developer that has a very strong suite of features and produces great results (for me). Its weak point is the fact that it is not exactly cheap (about $145 US), and was not localized by native English-speaking translators, so its English is rather wonky. But it is a powerful tool that produces the closest to "Olympus color" of any non-Olympus developer I've tried (well, I haven't tried that many, admittedly)--and it's much faster and more powerful, IMO.


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