Nov 12 2011

What is RAW? (part 1)

A Beginning Note

Some people tend to get into a religious war when it comes to subject of shooting RAW vs. JPG. The truth is that there are advantages and disadvantages to either approach. This aricle is simply meant to outline some of the differences. Not all digital cameras can capture RAW files – most pocket cameras cannot. Many people who shoot RAW with their digital SLRs also shoot JPG with pocket cameras, and are perfectly content to do so.

A Few Words About JPG

Before we get too far into the subject of RAW, let’s talk briefly about JPG photos.

JPG is the most widely used format for capturing and storing digital photos. It rose to prominence largely because, in the early days of digital photography when memory cards had small capacities and were fairly expensive, it allowed for photos to be stored in a compressed format (allowing more photos to be stored on a card) while still maintaining a reasonable degree of image quality.

JPG uses a type of compression known as lossy compression. That means that it “throws out” information in the photograph that it doesn’t think you’ll miss, in order to end up with a smaller file size. It’s similar to MP3 or iTunes files in the audio world. MP3 (as well AAC) is a lossy audio format – it throws out the parts of the audio that it thinks you won’t notice in order to keep the file size smaller. It’s called “lossy compression” because, once you create the JPG or MP3 file, you can never go back to the full uncompressed quaility – that information is gone forever.

With both JPG and MP3, you can control the amount of compression when you make or save a file. That’s why in most cameras you can select the quality of the JPGs – settings like “Standard”, “Fine”, and “Superfine”, or “SQ” (standard quality), “HQ” (high quality), and “SHQ” (super high quality). Higher quality settings result in higher quality (less compressed) images, but at larger files sizes. Lower quality settings keep the file sizes down (so you can store more photos on your card), but at a lower image quality. Too much compression makes the picture look blocky, and makes similar-colored areas like walls and sky look “splotchy”.

Since memory cards have become larger and comparatively inexpensive, it’s a good idea to use the highest quality settings when shooting JPG.

RAW vs. JPG

Here’s what happens when you press the shutter button to capture a JPG file:

  1. The shutter opens for the specified time and the camera’s sensor collects the light.
  2. The camera uses a “special recipe” to take the information from the sensor and turn it into an image. This special recipe affects things like rendering color, image contrast, color saturation, etc.
  3. The camera applies the white balance settings (either “Auto” or a WB setting you’ve chosen).
  4. The camera compresses the image according to the quality (compression) settings you’ve set up.
  5. The camera applies any other special settings you’ve set up in the menu (vivid color, more or less shapening, etc.)
  6. The camera writes the JPG file to the memory card.

By contrast, here’s what happens when you press the shutter button to capture a RAW file:

  1. The shutter opens for the specified time and the camera’s sensor collects the light.
  2. The camera takes this raw sensor information, makes a note of the white balance setting (but doesn’t apply it), and saves this information to a RAW file on the memory card.

That’s it!

When shooting RAW, you “develop” the raw image data into a photograph on your computer.

You may be asking yourself, “But isn’t that more work than shooting JPG?” And the answer is “Yes – sometimes”. In reality, a RAW workflow doesn’t have to be any more time consuming than a JPG workflow. That’s because most RAW development programs allow you to download photos from the card, batch rename, preview, straighten, crop, make image adjustments, reduce noise, and save to JPG all within one program. In most cases, the only time you need to open Photoshop or a similar editor is if you want to work with layers and/or specialized plugins.

In Part 2 of this article, we’ll talk about two key areas in which RAW can offer an advantage over JPG when it comes to editing your photos.


Sep 7 2011

On Photography, Skill, and Being Creative

I recently read (well, mostly skimmed) a book called The Creative Habit. It was mentioned in a post by Merlin Mann several weeks ago, and while I haven’t gone as ga-ga about it as he has, I thought it made some useful points. Although the book was written by a choreographer, the ideas can be applied to any creative endeavor – art, music, design (of any kind), even programming.

I came away with a couple of main points from the book…

Point #1 – Creativity isn’t a gift reserved just for the chosen few. I’ve seen quotes from some artists suggesting that “you’re born with it or you aren’t”, and that it’s not something that can be learned. Hogwash. Such an attitude is driven either by an over-inflated ego or by a fear that maybe they’re not as uniquely gifted as they’d like to believe. It’s certainly true that some people are more naturally gifted in particular areas than others, but while you may never be “the best”, it’s certainly possible to get better, and maybe even get “good”.

Point #2 – Creativity takes a lot of work. This is the point that served as sort of a wake-up call for me, even though I instinctively knew it to a degree. Creativity isn’t about waiting around for the inspiration to hit. It’s about going through the motions, on a regular basis, whether you’re feeling particularly creative or not. (Hence the name of the book – The Creative Habit).

Here are the implications in terms of my photography hobby: If I wait around to go out and shoot until I’m feeling really creative, I’ll be shooting much less often. And that’s because I never know when the creative muse will come calling, and when it does, there’s a decent chance I can’t act on it because of other responsibilities (e.g., my paying job). So I need to regularly put myself in situations where I can practice creativity – making myself go out and shoot…putting that into my schedule.

And I have to say – forcing myself to do it is starting to help me notice more creative possibilities. Just sitting here now on my couch, typing this entry, I noticed 5 potential photographic subjects within about a minute. And that motivates me, and encourages me, and gets my creative juices flowing in a way that sort of feeds on itself. I know there will still be times when I get stuck in a rut creatively. But having the habit – making myself go do it – is the best recipe for getting un-stuck.

So here’s to the hard work of creativity…


Sep 5 2010

The Great Megapixel Scam

After seeing camera after camera continually released by the major (and countless minor) camera makers, each touting more megapixels than the last, it’s time to help get some basic facts out to the camera-buying public:

More is not necessarily better.

That probably seems counter-intuitive to a lot of people. On the surface, it would seem obvious that given the choice of a 6-megapixel camera and a 10-megapixel camera, the 10-megapixel camera would be superior, and the better value. But that’s often not the case.

Let’s forget about the bogus and deceptive “effective megapixel” ploy used by many no-name digital camera makers. They take a lower resolution sensor (say, 4 megapixels), and digitally enlarge the image – in-camera – to a higher resolution (say, 7 megapixels), and advertise the camera as a 7-megapixel camera. You’re really only getting 4-megapixel quality, and even that quality is dependent upon the lens quality, the in-camera imager circuitry, etc. So let’s skip those and talk about true image resolution.

Say you’re comparing two current models of compact digital cameras from a reputable camera maker (Olympus, Nikon, Canon, Pentax, Kodak). We’ll assume they have decent quality lenses and imaging circuitry. One is a 6-megapixel model, and one is a 10-megapixel model. Which is going to give you the best image quality? All other things being equal, it’s very possible that the 6-megapixel model will give you better images.

Here’s why…

A digital photo is made up of lots of pixels (an abbreviation for “picture elements”). Pixels are lined up in columns and rows across the image sensor. The average image sensor (the part of the camera that collects the light – that holds the pixels) for a compact digital camera is about 3/8 of an inch across – significantly smaller than a postage stamp. The megapixel count refers to how many millions of pixels are squeezed onto the sensor – 6 megapixels equals approximately 6 million pixels.

So here’s the deal: When it comes to pixels, size matters. And not just the size of the pixel, but the space between pixels matters too. Each pixel collects light and determines colors. The bigger the pixel, the more information each pixel can collect. What’s more, each pixel sends the information it collects to the camera’s processing chip via an electrical current. The more pixels are crammed onto a sensor, the hotter the sensor becomes, creating image noise (a kind of grainy or dirty appearance to the images, especially noticeable on indoor and low-light shots).

If camera makers increased the size of the sensor as they added more pixels, then a higher megapixel camera would probably be the better choice. But what camera makers tend to do is simply cram more pixels onto the same size sensor, and then rely on noise reduction software inside the camera to keep the noise down. But in reducing noise, the noise reduction process also reduces image detail. You may not notice the loss of detail on a 4×6 print, but it may become very noticeable on a 5×7 or 8×10 – the photo just doesn’t look “sharp”.

Thankfully, camera makers seem to have slowed in their race for more megapixels.

In all honesty, 5 megapixels is generally plenty to get a good quality print up to 8×10 size, unless you do MAJOR cropping of the image. So unless you plan to print poster-size images (in which case you should use a digital SLR, which has a larger sensor size to start with), don’t get caught up in the megapixel hype.