Posts Tagged ‘RAW’

Processing Digital Photos, from the Camera to Screen or Print

October 25th, 2009

Anyone who takes a lot of photos knows that the time spent behind the camera is only one small step to getting an image you are proud of onto the web or printed.  Higher-end cameras tempt you to make this process harder by capturing your photos in their RAW format whihc requires processing to get the photo into the industry standard JPEG format which you can send to your friends and your mom.

The leader in RAW processing is Adobe with their popular Adobe Photoshop Lightroom application, now in version 2.  Lightroom makes it possible to assign tags to your photos, rate them and apply improvements to the colors, brightness and contrast before exporting a JPEG file to post to your blog or to send to the printer. 

Workflow:
While Lightroom is more powerful and easier to use than some of it’s competitors, I would hardly call it “easy”.  Photographers describe the myriad of steps they use to take a RAW digital photo on the camera and turn it into something that they can share “Workflow”.

My workflow is probably less complex than most professional photographers, but it is still cimbersome enough that I regularly get months behind in processing my photos.  My workflow begins in the first tab in Lightroom labeled “Library”.  In this phase, my goal is to 1) label the photos appropriately so I can get back to them in the future and 2) identify those photos which are good enough to share, and those which look like they could be great.

1) Labeling
To label the photos, I assign tags to the people in the photo, and will sometimes add a short description of the photo.  This is also when I try to assign the location where the set of photos was taken by specifying the Country/State/City/Location.   Recently, I have tried to assign coordinates to my photos by using clever software that uses a tracklog with the timestamp on the photo to interpolate where the photo was taken. (A tracklog is a recording on a GPS device of where you are every 30 seconds.)  Lightroom should really include built-in support for this, but in the meantime a person named Jeffrey Friedl has created a Lightroom plugin to assign the coordinates where a given photo was taken based on a tracklog from the same period. 

I also assign a Star rating to the photos which I like.  Roughly speaking, I assign 2 stars to any photo which is either decent, or a poor quality image that is important to tell the complete story of an event.  I try to assign 3 stars to the best 2 to 4 photos of a given event.  These are good photos, but not my best.  4 stars is meant to mean “excellent”, a photo which is great both in subject and composition.  5 stars is a concept I challenge with.  I know my photos could always be better so I am hesitant to give anything this rating.  I do take good photos, so I should me more willing to rate a few photos a year “5 stars”

2) Processing
After tagging, I must process the photos.  This varies greatly from photo to photo, but the most common changes I make are an adjustment to the brightness of the image, the increase of Contrast, and tweaking the balance of brightness and contrast in the shadows.  I also use the Neutral Density Gradient filters pretty often to correct a blow-out sky.  If none of this is enough to make the subject, usually someone’s face, bright enough or having enough contrast, then I will use the localized tools to correct the broghtness / contrast in an area of the image.  Both of these localized edits are new to Lightroom Version 2

Finally, after tagging and processing, I export my photos which are 2 stars or greater into my public photo library.  This generally yields 1/2 to 3/4 of the original photos.  When I export photos, I keep the standard resolution and set the JPEG compression settings to 80 of 100.

Free upgrade to your Canon Point-and-shoot Camera

October 14th, 2009

A quick primer on Digital Cameras:
Most folks who get seriously interested in Photography eventually upgrade to a Digital SLR Camera.  These bulky cameras have a number of features that a cheap point-and-shoot lack:

  • The most obvious difference is the ability to change the lens based on what you are trying to photograph. 
    Some folks make do with a single lens which will be good at everything, but great at nothing.  We carry three lenses at the moment; each is great at something different. (The 10-22 is very wide, the 30mm is fast and sharp, and the 70-200 can zoom and is also very sharp.)
  • One of the other important features of a Digital SLR is that the sensor which gathers light and creates the digital image is comparably large. 
    The sensor of a point-and-shoot is about the size of a tic-tac, whereas the sensor on a SLR is about the size of a postage stamp.  This gathers much more light, and leads to a sharper image with less noise.
  • The last big difference is the ability to shoot in RAW format. 
    Cameras record anywhere from 10-16 bits of information for each pixel in the photo, but when you convert the image to the standard JPEG format, you are limited to 8 bits of information for each color/pixel.  If this conversion occurs in the camera, you get easy to use JPEG files on your memory card, but you cannot go back to the original data if you want to make changes to the brightness or the color balance.  There is no technical reason preventing a cheap camera from saving photos in RAW format, but rather they do not offer this option as it drives sales of higher-end cameras.

So, how do I upgrade my Canon point-and shoot camera?
This is where the hard work of a community of hackers comes in with a program called Canon Hack Development Kit, or CHDC.  They have put together a hack which allows a inexpensive Canon Point-and-Shoot camera to do many things that Canon did not intend.  The most significant new feature is the ability to save yoru photos in RAW format.

I installed their software on my camera and fought through their poorly-designed menus to set it up, but it really works.  I shouldn’t overstate the value of saving RAW images from a low quality camera. There is only a little extra data to work with in these RAW images, and the resulting files are significantly larger than their JPEG counterparts.  The excitement is further weakened by the fact that you have to run a crappy utility (DNG4PS2) on your PC to convert these RAW files into .dng files which are compatible with popular software such as Lightroom.

Update (8:29pm)
I wanted to see if the RAW files from my camera actually contained extended dynamic range compared to the camera JPEG, so I did a quick test.

The images below are crops from an overexposed portion of a photo taken on my Canon SD630.

Image 1. This is a crop from the unmodified in-camera JPEG.
Image 2. I took the in-camera JPEG and decreased the exposure in Lightroom, -4.00
Image 3. This time I applied the same -4.00 exposure to the RAW image.
As you can see, there is definitely additional information in the RAW image which was lost as pure white in the JPEG.