Friday, August 12, 2005
Looking back, there's not much value in those old images. However, a recent article on Andre Gallant in Outdoor Photographer got me interested in his technique. Basically he sandwiches two slightly overexposed slides of the exact same subject together -- one blurred and one sharp. I did the same in PhotoShop -- with layers, gausian blur, opacity, levels, and unsharp masking -- on some early images I took with the Mavica with some great results.
Thursday, August 11, 2005
There is one amount of light that makes your exposure work but two ways to get that light into the camera: the size of the hole and the length of time the hole is open.
These options bear an inverse relationship, that is, as one is lowered the other is raised in order to keep the light entering the camera the same.
F-stops are the way to change the size of the hole, or aperture. The diameter of the hole is represented in the f-stop number as a denominator. The "f" in f-stop is focal length and that will vary from lens to lens, but the formula is always the same, F/2.0, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, etc. As the denominator gets larger the hole gets smaller. And it does so by halves. Each successive f-stop has half the area of the one before. (You can find this to be true by multiplying the square of the numbers by Pi.)
Shutter speeds are how you change the time the hole is open. On older film cameras, the shuttter speed options roughly double, for instance, 1/250, 1/125, 1/60, 1/30 etc., each an increasingly long fraction of a second.
On newer cameras you may have additional stops and speeds but they are inversely proportional on all cameras.
So if you know how much light it takes to make the photograph, you can arrive at that amount in various mixtures of size and speed. Why would you do this and not just take the automatic setting from the camera? Changing your aperture is done principally to change the depth of focus, or the range of sharpness in your composition. Changing your shutter speed changes your your ability to freeze motion or hold the camera still without introducing motion from your own movement.
The smaller the aperture, the longer the range of objects in focus. The faster the shutter, the more likely you can freeze motion.
Often in landscape photography, you want infinite depth of sharpness, so you choose a small aperture and a long shutter speed. To keep the shot still, you need a tripod and no wind. Portraits or close-ups may be better with only a small portion in focus and distracting elements completely blurred into the background. Movement in a waterfall or vehicle may dictate that you intentionally blur portions of your image.
What if you want both depth and stopped motion? To extend your choices, change your capture speed (or ISO equivalent). This resets the light requirement in the camera for your photo and ratchets your shutter speed and aperture ratio to a new point. It's still an inverse relationship but it now works from a point where you might be able to stop motion and get more depth of focus. The trade off, however, is noise or grain. Fast ISO settings tend to introduce more noise in a digital camera because the sensor must work with less light. Less light strains the technology that converts light into an image and mistakes are more common, seen as pixels that are not accurate (color noise) or grain in film.
Wednesday, August 10, 2005
Watch overlaps between the unrelated objects in the composition. They are often best separated by neutral space. If you have repetition of form or objects, consider how many are in the photo. Given a choice, pick an odd number. People seem to like an odd numbered collection best.
Tuesday, August 09, 2005
Being in a place and being in a moment are two intersecting lines that never touch again. You can go back to the place but only ahead to another moment. As Edward Abbey put it, " When I return will it be the same? Will I be the same? Will anything ever be quite the same again? If I return." The camera can preserve our awareness of that intersection of place and time.
Monday, August 08, 2005
Most people think a cloudless sunny day with the light behind you is best for photography. Actually, this is a very difficult lighting condition. High, top lighting makes too much contrast, too close to the lighted objects. Also watch out for broad areas of brightly lit or near-white colors, they make a distracting foreground.
Your mechanical eye isn’t as versatile as your biological eye—there are simply some lighting conditions beyond your camera's capability. Beware of any situation with more than four f-stops difference within your frame. Shade and sun can be evened out with graduated filters but speckled sunlight near trees pose impossible exposure problems. The light will bleach exposures to the point where the speckled pattern overwhelms the viewer's attention.
To make your photographs “color-safe,” use care in your application of sunlight. Generally, shoot across or into light that’s less than 30 degrees from the horizon. This means your best time to shoot is at the ends of the day. When the sun is near the horizon light has a yellow bias because this part of the spectrum is magnified by the atmosphere it shines through. These warm tones enhance your subject and the light is also less bright. And keep shooting on gray days—they provide perfect diffused lighting for portraits, close ups, and saturated color if you use a polarizer.
Sunday, August 07, 2005
Friday, August 05, 2005
Moving the subject off-center will tend to divide the photo into thirds, common advice for composition. The thirds phenomenon is a result, not an objective; it's asymmetrical balance and the off-center attitude that makes the composition work.