why I use raw photos

[dsblack]

For anybody wondering why you would want to take pics in raw format, here's an extreme but excellent example. It's a picture I took last summer in Colorado.

I shoot using raw+jpg, which means it saves the raw (.cr2) format and the jpg format -- two files per photo. Raw format has a higher range of color -- 12 bits per color instead of 8, which means 4096 shades (of each of red, green, and blue) instead of 256. And the camera doesn't do any post-processing on the image; it just saves exactly what came through the sensor. Anyway, the larger color range means there can be more data stored than you can see on the screen, which means you can edit the photos to tweak it and pull out more color from the areas that first looked too bright or too dark.

This is the jpg that came straight out of the camera. (I resized it to upload it, but no color balancing or any other editing.) The camera processed this a little bit to make it look better, but it didn't do much.

original jpg - click image for larger version

This is the raw image (.cr2 for mine) that came out of the camera -- just converted to jpg (and resized) to show what it looks like with no tweaking. The result is almost the same as the jpg, and the colors actually appear a bit flatter/duller. This is normal; raw images are rarely used as-is; they're intended to be edited first.

original raw (cr2) - click image for larger version

And here's what happened when I started with the raw image and played with the colors in Photoshop. I did more work on this one than most of my photos, including some selective editing (different color balance for different parts of the photo), but there was a lot of great color hidden in there. There would be very little chance of pulling this kind of color and detail out of the camera's jpg -- you'd probably have to do some more artificial coloring, and I wouldn't have the time or skill to do that so it looked good. I'm guessing this took me 20-30min to edit. A normal outdoor scenery photo probably takes me about 5min, or 10min at the most. I'm guessing even a skilled artist would need hours to tweak the camera's jpg version of this photo to look good.

edited raw (cr2) - click image for larger version

The end result is much prettier and much more realistic.

So that's why I use raw image format for my photos, and it's also why I take the time to edit my photos. Most photos won't have this dynamic a change, but it can still often make a noticeable difference.

...

For more details on raw images, try "raw image format" (without quotes) on Google:
http://google.com/#q=raw+image+format

Skimming through the first few results, it looks like there are some good articles that explain it nicely.

I think the first hit, the wikipedia article, spends too much time making sure they mention every possible tiny technical detail. So unless you really want the trivia, you might skip that one. The other pages I saw looked like they hit the right amount of technical detail while keeping everything readable for the "average" camera geeks like me.

[keithsnell]

Dan,

Excellent example of why we should use raw format when possible.  Thank you very much for taking the time to post this.

Keith

[burzilai]

Thanks Keith for explaining RAW. In the last month I have been using RAW to shoot my pics and editing them and yes they turn out to be more realisitic in terms of color without losing picture quality. Aside from adobe photoshop do you know of any software that will read and edit RAW? the adobe photoshop elements I use doesn't even read RAW files, so I downloaded piccasa which pretty much okay.My question is if I convert my RAW to JPEG (as is, no editing. just "save as") so that I can open it and read it in photoshop elements, will it still give me the 12-bit? I know the pro adobe like CS4 or lightroom edits RAW but they're pricy. Just wondering.

Thanks again,
Shee   

[keithsnell]

Sheila,

To answer your last question first , once you convert from raw to JPEG you have essentially "truncated" that 12 bit file to an 8 bit format, and lost all of the additional information available in the raw file.  It is best to do all of your exposure adjustments, etc., in the raw processing software, and then convert to JPEG.

I would start with the camera manufacturer's software.  All of the manufacturers provide at least some rudimentary ability to open and edit the raw files with the (free) software they provide with the camera.  What camera make and model are you using?  If I know that, I can help point you in the right direction. 

Also, what version of Photoshop Elements do you have?  Elements does have the ability to open an process raw files (through the use of the Adobe Camera Raw plugin) however, you might need to update to a "current" version of Elements if your camera is fairly recent. 

Keith

[dsblack]

There are also batch converters out there to convert a whole set of raw files to jpg (or tiff or other format) together.  As Keith mentioned, most SLR cameras come with software from the manufacturer to view and convert, and I know the Canon software that came with my XT would do batches.  There are also some free options.

For the Mac, Preview comes with the system (in your Applications folder) and will view raw images.  Err, I think.  I just tried it on a MacOS 10.3.9 machine, and it didn't work, but I'm pretty sure it did on my home computer, so maybe it's 10.4 and above.  It looks like it will do conversions, but I don't think it will do batch conversions.  Also on the Mac, for a slide-show-style viewer (but not for converting), I use JPEGDeux.  And for a quick viewer, new with MacOS 10.5, there's a nice feature built into the system, so if you have a picture selected in the Finder, you just hit the space bar, and it will pop up a fairly large preview of the image, and you can use the arrow keys to go back and forth among images.  (Definitely works with raw images.)

For Windows, for a free program, I use IrfanView.  It's a good slide show program, handles raw files fine, and it will do conversions, even in batches.  Can even do pretty good quality resizes and some other basic adjustments (like rotations and simple color adjustment).  Hard to beat that for free-and-easy, so if you use Windows, I highly recommend it.

I also have a longer comment and explanation on the file formats, but I'll split it into another post since that makes a good breaking point.  (I'll post it right here in a few minutes.)

[dsblack]

I mentioned the tiff image format earlier, which brings me back to your question about jpgs and bit depth.  Keith already answered your question for jpgs (correctly, of course).  But this brings up the point of other formats you might want to use in some situations

First, for anybody who is unfamiliar with the technical stuff: Most images that you find on the web are jpgs, which as Keith said, are only 8-bit.  That means 8 bits per color per pixel.  There are three colors in each pixel (red/green/blue, or RGB), so that means 24 bits per pixel.

Side note: For some reason, most of us have gotten into the habit of calling a jpg an 8-bit image, but we say most modern monitors are 24-bit color.  We're really saying the same thing; we're just referring to the images files by the bits per color per pixel, and the display by the bits per pixel.

You can think of an image like a bucket of paint.  A jpg would be an 8-quart bucket.  You take a picture and get a raw file that fills a 12qt bucket.  If you try to pour the 12qt bucket into the 8qt bucket, 4 colorful quarts overflow and are lost.  (Yeah, technically, it'd be more like three 8- or 12-quart buckets -- red, green, and blue -- so you can imagine the triplets of buckets if you really want to.)

There are some formats that are 16-bit -- like 16qt buckets -- so you can "pour" 12-bit raw images into them without losing anything, and even have room left over.

The tiff format that I mentioned earlier supports 16-bit images, so you can convert raw images to tiff without any loss.  However, tiffs tend to be big -- my camera, which takes 8MP images, produces raw files that are usually "only" 10-12MB each.  Converting results in 45MB tiffs.  In fact, I think that's what Canon's batch converter coverted them to.

The tiffs may be big, but an advantage of tiff is that just about any image program can read them.  Many of the online photo printers accept tiffs, so if you really want that extra bit depth, it's a format to consider.  (Usually, 8bit is really good enough for the final product -- and for the human eye -- unless you're really going for professional caliber.  The point in starting your editing process with the 12bit images was to give you a better range to pull from, and then "narrow down" into the final image.)

Testing things with Photoshop, it looks like the png format also supports 16 bits (RGB/16), and I ended up with a 35MB png file for my 8MP photo.  Photoshop files (.psd) also support RGB/16, of course, and I think Apple's pict format (.pct or .pict) might, too.  Of those, png is a very common format, but fewer programs will read psd or pict.

[keithsnell]

Dan,

Good info. 

To summarize, the recommendation is to do the majority of your exposure and color corrections in a format with a larger bit depth (raw) and then convert to an 8-bit JPEG towards the end of your processing.

Keith

[burzilai]

Got it,  I have Nikon D60 which is .NEF (RAW) and adobe photoshop element 6, it doesn't even open the >NEF file, that's why I use piccasa to open & edit .NEF then it saves it JPEG. what plug in do I have to use in order to edit .NEF in adobe? I can view .NEF file in MAC but can't edit it using adobe. Although piccasa does the job i was hoping i can edit it in adobe coz it has more features.


thanks again

[keithsnell]

Sheila,

Try using Nikon View NX to open and edit the NEF file.  You should have received a copy of that program in the box with your camera.  If not, you can download it from the Nikon site.  View NX is free, and does a great job with basic exposure, white balance and tone curve corrections for Nikon raw files.  Once you've done those corrections, it is safe to save the file as a JPEG and do the rest of your processing in Elements.

The version of Adobe Camera Raw that shipped with Elements 6 won't open a D60 file; however, you can update the Camera Raw pluggin to version 5.3, which will open the D60 files.  (Actually, anything past version 4.4.1 will open D60 files, but you might as well update to the latest version of ACR that will run on Elements 6, and that is version 5.3)  You can find instructions for downloading and installing the ACR update on the Adobe site.  Let me know if you need more help with this.

Keith

[burzilai]

Hi Keith,
I   do have the Nikon View NX but it only let me view it, i didn't see anything to edit it, but maybe I need to look harder coz it does say in the manual it edits nef.
Thanks,
shee

[Melissa]

Hi:)

Thanks for an excellent explanation on difference RAW and jpeg.

I started shooting RAW just after getting my camera and don't look back...(it's only been a year though:)
I'm still learning everday on how to edit my photo's and get the best possible result, as with your example.

One question though for Dan:
How did you manage to do away with the fog on the hills and make them so much clearer in pp?
I have a few pictures of a recent holiday where all my hills are foggy. Could you be so kind as to share your technique?

[keithsnell]

One question though for Dan:
How did you manage to do away with the fog on the hills and make them so much clearer in pp?
I have a few pictures of a recent holiday where all my hills are foggy. Could you be so kind as to share your technique?

HI Melissa,
 
I hope Dan answers too, but in the meantime I thought I would answer from my perspective.  I usually find that increasing the contrast ( by adjusting the black point so that the darkest blacks are just touching the left edge of the histogram display) is the best way to alleviate the "foggy" look on distant hills.  Notice that the dark tones in Dan's adjusted image are much darker than they were in the original, that is an indication that he has adjusted the black point.

By the way, what raw processor are you using?  (Techniques vary depending on the processor).

Keith

[Melissa]

Hi Keith

Thanks for the explanation.

I am using Adobe Camera Raw and CS2. I'll have to get CS4 when I'm rich and famous:)
So, if I understand correctly, when in ACR I would just move the "shadows" slider up and down to get the desired result? Or is there another way in photoshop itself (like curves or levels - still learning these too!)

Thanks:)

[keithsnell]

Hi Keith

Thanks for the explanation.

I am using Adobe Camera Raw and CS2. I'll have to get CS4 when I'm rich and famous:)
So, if I understand correctly, when in ACR I would just move the "shadows" slider up and down to get the desired result? Or is there another way in photoshop itself (like curves or levels - still learning these too!)

Thanks:)

Hi Melissa,
Yes, moving the "shadows" slider up in ACR (in CS2) is how you would adjust the "black point."  (This control was renamed to "blacks" in CS3  .)  Typically you would want the left end of the histogram to just touch the left side of the histogram display.  This sets the blackest parts of the image as true black, and adjusts all the other tones in relation to the black point.

You can do essentially the same thing in Photoshop by dragging the black point slider on the Levels or Curves adjustment; however, it is always better to do your adjustments in your raw processor where possible.