Shooting in RAW?

[MarkBarbieri]

Some other things that I don't think have been mentioned:

RAW Files Aren't Standard
RAW is not a a single format. In fact, the RAW format is different for different cameras and different companies. I don't think that any camera companies publish their RAW format and I've been told that they are mildly encypted. It's really easy to find RAW converters for your camera today, but if someone goes to look at your pictures 50 years from now, it's likely to be much harder. It's very likely that people will be able to easily read JPG files (assuming they can read the media it's stored on) for a very long time. With RAW files, I wouldn't be so confident.

Adobe has published a universal RAW format called DNG. If you are concerned about being able to use your RAW files in the distant future, you might be better off converting them to DNG files.

RAW Conversion Isn't a Standard
If you shoot RAW you can choose several different RAW processors today, each of which might demosaic the original bayer array differently. You might find that one yields better results than your camera.

More Than White Balance
A lot of people have made the point that the RAW file hasn't been altered by a white balancing process. Other things done in RAW conversion usually include sharpening, contrast, and saturation adjustments. If you want to control these yourself, shooting RAW is the way to go.

Color Space
The numbers inside your picture file don't really map to colors directly. Instead, each number is mapped to a color based on a "Color Space". The overwhelming majority of JPGs are saved using sRGB. In fact, I think versions of Internet Explorer prior to 7 just assume that all JPGs use the sRGB color space.

With a RAW file, you can convert to a different color space, like Adobe RGB, without losing as much information. sRGB covers a smaller gamut than Adobe RGB. If you are printing to a device that has a wider gamut than sRGB, and many modern ink jets do, there are some colors (typically extremely saturated colors) that you could print from an Adobe RGB file that you can't print from an sRGB file because they lie outside the sRGB gamut.

Even if you don't know anything about color spaces today, you might learn about them later. In that case, your sRGB file will never be able to get back the wide gamut data that you lost when you shot JPG.

 

[Groucho]

Actually, now that I think about it, it may be only 8 megabytes for a RAW image if it's really an 8 megapixel, 12 bit depth bayer array. That's because each pixel in the original image is just red, blue, or green. It gets the other colors from the pixels around it.

From what I've read, Canon uses lossless compression on their RAW files while Nikon and Kodak use slightly lossy compression algorithms on theirs, so I guess I was even more wrong with my original statement.

Pentax (at least the ist DL) uses no compression and the 6mp raw files are about 10 megs, FWIW. I seem to have heard that in-camera compressed 6mp ones are about 7-8 megs.

It would be nice to have a raw standard, but I doubt we'll see one any time soon, especially if the main candidate is owned by Adobe... who aren't known for giving anything away except viewers for their proprietary formats.

 

[MarkBarbieri]

In the case of DNG, Adobe has published the format and allows royalty free use, so anyone is free to build a reader or a writer.

I think the same is actually true of PDF. While Adobe makes good money off of selling copies of Acrobat (the version that writes), you can find plenty of free PDF creators like CutePDF.

 

[0bli0]

good points, Mark. and also very pertinent to the discussion. *warning* semi-techy items below that can be very confusing. proceed with caution or ignore it all together.

RAW files are basically dumps from the sensor as the camera gets it. they definitely aren't standard. in fact, they are different from single vendor. Canon has different RAW formats for pretty much all of its cameras. they then release new versions of the RAW conversion tools.

Apple adds RAW support to their OSX operating system as new cameras from popular vendors are available. Adobe releases new versions of their ACR program - again to accomodate newer cameras. they also just released a new DNG converter.

colourspace and also colour profiling/matching is a hugely important part of the shoot/edit/print equation. i'd say around 95% of the people out there shoot sRGB and that's fine as they don't know there are other colourspaces available. then there are people that read things on forums about 'wider gamuts', such as AdobeRGB. so they set their camera to use it and ten find their pictures look wildly unsaturated and dull - because as Mark said, browsers generally display jpg files in sRGB - even when the colourspace is embedded within the image file. if you're thinking 'what the heck is he talking about', i'll highly recommend to just ignore this section and stick with sRGB (don't worry about making any changes). it's all about potentially capturing a wider range of colours, but generally it will need to be converted to sRGB and there is way too much margin for skipping a step along the way.

something you should't skip, on the otherhand, is colour profiling. if you are printing often - whether at home or through a lab - you may want to consider profiling your monitor. what does this mean? you put a device called a colorimeter on your monitor and it reads how your monitor displays certain colours on the screen. there is no universal law that says (rgb) 242, 013, 044 is a certain colour red. what profiling does is get your monitor to as accurately as possible, represent the colours that you see in a consistent fashion. so when i look at my DD wearing a lilac shirt on the monitor, her skin colour and the shirt colour are now a sort of pseudo standard that i can then print (on a colour profiled) printer and have a pretty good 'what you see is what you get' printed image. note that LCD panels aren't as accurate as CRT monitors. also monitors change often, so you should update the profile every month or two.

 

[MarkBarbieri]

here are people that read things on forums about 'wider gamuts', such as AdobeRGB. so they set their camera to use it and ten find their pictures look wildly unsaturated and dull

LOL - That almost exactly sums up my first foray into playing about with color spaces.

 

[PaulD]

ObliO is right about profiling your monitor. Sometimes the difference is not too apparent but sometimes it's HUGE! If you get your photos printed at a lab you'll definitely want to do this so that you won't be dissapointed when your prints don't look the same as as they do on your screen.

 

[Groucho]

I was reminded on this thread while looking at an early review of the new Pentax K10D over at DPReview - apparently it's the first DSLR to support the Adobe DNG format, as well as an updated version of their own RAW format (now with RAW+JPG and compression), plus let you convert a RAW to JPG in-camera, giving you control over WB, sharpness, contrast, exposure, etc, etc. Pretty slick... it's definitely on my wish list.

Hopefully the other DSLR players will follow suit and move to a standardized RAW format, too. Having proprietary formats helps no one and hurts everyone.

 

[0bli0]

the only downside about DNG at the moment is many iterations are wrapped around the camera's proprietary core raw ('bulletproof' option), as only Adobe ACR and a few other programs read box stock DNG. this makes the file size nearly as large as a .TIF file.

hopefully the K10D's DNG is not the 'bulletproof' flavor and will set a trend for manufactures for standardisation in the future.