Thursday, June 24, 2010

White balance and file management.

This week we reviewed some great photos of the Riverwalk in Council Grove.  Unfortunately, it's tough to get a real good look with a projected image, I'll see if I can improve on that next week.

Color temperature is how photographers describe the color of the light affecting the scene they are trying to capture.  The eye and brain automatically adjust to changes in light, whether it be sunlight, florescent lights or those weird yellowish lights you find in gymnasiums.  Cameras can adjust and make a "guess" using a setting known as automatic white balance.  The AWB can be usually pretty accurate, but often is a bit off in sunlight and when shooting landscapes.  Color temperature can be frustrating to deal with. The more accurate you set your color temperature, the less you will have to fiddle with your pictures later on.  Your camera will have the following settings:  sunlight, tungsten, florescent, cloudy, flash, K (for Kelvin, you pick the number), AWB (auto white balance, not the band from the 70's), and two triangles with a box in between, which is custom white balance.

Custom white balance is very valuable. . .it is usually very accurate and really helps in making sure your colors are very close to correct without needing to make a lot of adjustments later.  Canon and Nikon cameras have a custom setting where you take a photograph of a white or neutral gray object, then the camera sets the color balance from that. Products such as Colorright, ExpoDisc, Balna discs are useful for this.  An article I read recently recommended using a Melletta coffee filter.

File Types and Work Flow

Digital SLR cameras can produce different types of files for use in transferring your photos for publishing, editing, or printing.  JPEG file formats are smaller in size.  They can have different levels of quality.  Lower quality files are smaller, but contain enough information to create good photographs for use in websites.  Higher quality files are better for editing and use in printing. 

When a JPEG file is created in the camera, the camera makes a set of decisions based on the settings in the camera, including color temperature, amount of sharpening, noise reduction, contrast and color balance.  You can search your menu settings in the camera to find these and adjust as necessary.

The RAW file is a file that contains the entire gamut of information collected by the sensor, given the amount of light provided to it.  A RAW file has to be read by a specific program designed to interpret and adjust RAW files.  Canon uses "Digital Photo Professional".  Nikon uses "Capture NX".  Other commonly used programs are Adobe Lightroom (my favorite), Adobe Photoshop, and Capture One.

When you move a file to the computer to evaluate it, adjust it and move it to it's final destination, this is commonly known as work flow.  RAW files are perfect for work flow, as so many adjustments can be made without degrading the quality or the details of the photo.  Steps involved in work flow are generally the following:

1.  Download to the computer
2.  Sort and rate
3.  Adjust the image
      a.  exposure
      b.  white balance
      c.  color balance
      d.  contrast
      e.  sharpening
      f.  noise reduction
4.  Save

Software such as Lightroom and Capture One are specifically designed to improve your work flow.  They are fairly expensive ($199 plus) but if you do a lot of photography, they are definitely worth it.  You can download the Adobe Lightroom program here.  Download the CaptureOne program here.  Each program has a 30 day free trial.

Also the class had a couple questions about color management.  It's pretty obvious to see that an LCD projector doesn't have the same color as a color monitor.  Also, monitors have different color profiles. . .pictures can look different on different monitors.  All this variability really messes with your brain after awhile.  If you look at a portrait on one monitor it may look wonderful, but on another, the skin tones may be too red or too blue.  Again, you can spend some money to solve this problem.  You can calibrate your monitor with a colorimeter, such as Spyder or ColorMunki .  

Tuesday, June 15, 2010

Focus and Exposure

Tonight our emphasis was getting to know the camera and getting it off the "green zone", the automatic settings.  Shooting manually allows you to control shutter speed, aperture and ISO.  These are the three components of exposure of a photograph.

Aperture is an opening created by metal leaves in the lens.  The size of the aperture opening is expressed by numbers ranging from 1 (wide open) to 32.  The aperture number itself is actually the lower half of a fraction that expresses what fraction of the lens opening is allowing light in.  1/2.0 (F2.0) allows one half of the light in, where 1/16 (F16) allows 1/16th of the light into the sensor.

Aperture not only controls how much light hits the sensor, it also controls how much of the subject is in focus. In photography, there are always trade offs.  If you want a wide open aperture for maximum light (F2.8, for example), the tradeoff is a narrow depth of field.  In other words, only just a few inches front and behind your focus point will actually be in focus.  Using a large aperture (the word "large" referring to the size of the opening, not the number), results in blurry backgrounds.  This can be handy if you are trying to isolate your subject from blurry surroundings.
      2.8             Large opening                     Shallow depth of field
      5.6             Smaller opening                  Deeper depth of field
     11               Much smaller opening         Much deeper depth of field. . . . on so forth

For a more "in depth"discussion of depth of field, go here

Shutter speed is the amount of time the shutter curtains allow light through to the sensor.  These are expressed
in fractions of a second. . .1/2, 1/15, 1/30, 1/60, 1/125, 1/250, and so forth.  Slower shutter speeds allow movement to be recorded as a blur on the sensor, while faster shutter speeds, say 1/250 and above, freeze the action.  People tend to shoot sports at 1/250 or faster to freeze the action.  Some things are actually more interesting with a bit of blur, such as waterfalls and rivers  Practice taking pictures of the low water dam at the riverwalk at different shutter speeds to gauge the different effects.

Camera shake is movement of the camera by the photographer.  Very experienced photographers can hold the camera very still, but for most of us, we move and jiggle a bit.  To avoid camera shake, shoot at as fast a shutter speed as you can to achieve the desired effect.  What shutter speed can you shoot at and avoid camera shake?  This is determined by the length of the lens you are using.  Most of the lenses used today are zoom lenses, that can zoom from 30-300mm.

                       Speed to avoid camera shake =  1/focal length (or faster)

for a photographer shooting zoomed at 100mm, shoot at 1/100 second or faster.

ISO is the sensitivity of the camera sensor to light.  If you don't have enough light to properly expose a scene, sometimes you need to increase the ISO setting of the camera.  Again, there are trade offs.  As you increase ISO, you increase the likelihood of digital noise, especially in darker regions of the photo.  When there is more digital noise, then often detail is lost from the photo.

It may be tempting to shoot at a lower ISO and just under expose the picture.  Don't do it.  Your best bet for a quality picture lies in getting the best exposure (i.e. best looking histogram) at the necessary ISO.

Histograms are your best bet for quickly determining if you have the proper exposure.  A histogram is a graph of all the shades in your picture, from dark (left side) to light (right side).  The camera sensor can collect detail from about 5 levels ("stops") of light.  Below that, areas will appear black, above that, areas will appear "blown out" or white.  Your camera has a highlight warning that will blink if overexposed.  This is affectionately referred to by digital photographers as "the blinkies".  Avoid the blinkies in your photographs.

Remember the assignment:  post your pictures to,

log in under flinthillsimages
password kansas

Upload your three best pictures of the riverwalk.  Include in your description your camera settings and name or initials.

Harold is still in the process of moving, so instead of him talking about light and composition, we will talk about a few more elements of digital photography:  white balance and file handling.

Several people on there comment sheets mentioned that they would like to do a better job with sports photography.  I attended a workshop last year with the team photographer of the University of Kansas. We will go over his keys to successful sports photography.  We may try to run over and catch some softball or baseball for practice.

See you next week!!

Monday, June 14, 2010

Photography Class starts 6/15

Our photography class starts Tuesday evening. Joel will be talking about how to use your camera off of the automatic mode. . .let your creativity out! We'll show you how to use your amazing camera.

We'd like to know what you would like to learn and achieve in this class, so we can meet your needs. Do you want to take pictures of sports? Are you tired of all your volleyball and basket ball pictures having a yellow cast? Do you want to make your family photos more interesting? Let us know what you want to learn and we'll show you how.

We'll see you there!!