Digital cameras: RAW and JPEG

[Steve Foss]

I see there's been some discussion about digital cameras here, and about RAW vs JPEG.

Here's what I've found after shooting digital as a newspaper and wildlife photographer for the last two years.

A note about RAW vs JPEG (you CAN do a lot with a JPEG if you have Photoshop or another manipulation program, but you can do LOT more with a RAW image).

JPEGs are smaller files than RAW. With my Canon 20D, a RAW image might take 8 megs of memory, while a JPEG of the same photo only runs about 3.5.

RAW images are not interpolated JPEGs, as mentioned by someone earlier. It's rather the other way around. JPEGS are made smaller than RAW by sacrificing color subtlety.

Here's how JPEGS stay smaller. The pixel is the basic unit of measurement for digital photography. A JPEG is compressed by taking adjacent pixels that have nearly the same color value and giving them all the same color value and collapsing them, so the file is smaller and faster to transfer from camera to card, from card to computer, etc. In RAW files, no pixels are collapsed. In other words, each individual RAW pixel retains its unique color and detail value.

JPEG is universal in that any program will handle them. Pretty much anyone with a computer can open one by double clicking on the photo icon. You double click on a RAW file icon and your computer won't know what to do.

RAW files are unique to individual manufacturers, and you have to have a program that has the RAW file "plug-in" for your camera to read and manipulate RAW files. Now, the software than comes with each digital camera usually contains a bare-bones program that will handle the camera's RAW files. Also, Photoshop versions from 7 up to the latest CS2 have the camera manufacturer's RAW plug-ins already in there, and they keep adding free plug ins every time a camera manufacturer comes out with new RAW parameters for new cameras.

OK, so what does this mean to you?

Here's an example. I have some digital images taken with a 6.3 megapixel Canon 10D SLR. Shooting in JPEG mode, the best I've been able to make sharp prints at is about 13x19. Shooting in RAW mode for a commission early last winter, I was able to make prints that were more than 20 inches tall and 30 inches long and sharp as a tack. Now, with the 20D I have (8.2 megapixels), I'll be able to shoot RAW and make prints about 30 inches tall by 40 or more inches long. Making an image bigger than the megapixel count wants it to be is where interpolation (adding pixels) is used, and that's how you can make bigger prints than you think you can initially. The latest versions of Photoshop are quite sophisticated at adding pixels. So maybe you've figured out why you can interpolate a RAW to a much larger image than a JPEG. Since you're adding pixels, and JPEG has already degraded the color subtlety, you get a muddy and indistinct print if you try to interpolate it too much. With RAW, you can interpolate much more before that happens.

OK, RAW vs JPEG. Which is right for you?

You have to weigh convenience with quality. By and large, unless you're making big prints, you'll never tell the difference between, say, an 8x10 JPEG and and 8x10 RAW.

You can do a ton to a RAW image in photoshop before it's technically opened up. Photoshop takes RAW images and "pre-opens" them into a screen that allows you to make all sort of changes to the original RAW image before it's opened as its own file in Photoshop. You don't get that option with JPEGs. So, with a RAW image that's underexposed, I can alter the exposure to compensate BEFORE I EVEN OPEN THE FILE ALL THE WAY! The best way to describe it is to liken a RAW image to a piece of undeveloped film. Just as you can change to some degree what's on the film by how you develop it, you can change white balance and sharpness and contrast and color saturation and exposure and a whole bunch of other things to a RAW image in advance.

Problem is, that all takes time, and you can't view RAW images without going through that whole process. So JPEG mode makes things a lot simpler for people who don't want to do all that.

For me, because any nature shot I take might need some day to be printed BIG, it's RAW, not JPEG. I actually set my camera to shoot RAW plus a small jpeg of each image, so I can pull up a little jpeg of each RAW image on my computer and chuck the ones I don't want. Goes a lot faster that way. ON a 1 Gb memory card (about $130 for a good 1 Gb card), I can shoot about 115 combination RAW/small jpegs before the card is filled. For the newspaper (sports, people portraits, news photos) I simply shoot large JPEG format. Newspaper resolution is fairly low resolution, and I don't need to worry about big enlargements.

So it's been bye-bye film! Digital now has all the color richness as film and, in many cases, better resolution. Yes, there's a bigger expense, but it's all up front (cost of camera, memory cards, computer, printer). No more paying for film and developing. The lenses that work on my Canon film camera work just fine on my digital body. Also, most photo developer shops and some big box stores now let you bring in a memory card and make prints right there, removing the need for you to buy a computer.

I just gave my venerable Canon Elan 2e film camera and my last rolls of Velvia to my daughter in law, an aspiring photographer herself.

Another note. Unless you drop $10,000 or so on a top-line digital body, you'll have a sensor that's bigger than an all-in-one but a bit smaller than the size of a standard photo negative. That means that any lens you put on a digital SLR will have a magnification factor, unless you buy an absolutely top of the line digital body, in which case you'll get a sensor as big as a photo negative. For Canon (the 10D, Rebel and 20D), the multiplication factor is about 1.6. That means that a 100 mm film lens, on the 20D, will actually shoot like a 160 mm. My 100-400 Canon image stabilizer then shoots like a 160-640 mm. Great, right? Sure, with telephoto, because it gets you "closer" to the subject. But remember, if you're shooting a wide angle and want that wide angle like, say, a 22 mm. You have to multiply it by 1.6, so you're actually shooting at about a 35 mm lens. Canon has come out with a 10-22 mm zoom that's really like the older 16-35 mm film lenses.

There are so many other advantages to digital (viewing each image on the camera's back allows you to get exposure just perfect and you can trash the ones you don't want, saving space on the card, and that's just one advantage.)

This is all just the SHORT version! If you really want to understand it all, you're gonna have to get a book.