The assignment for the week of 11 - 17 July 2011 is "Water." You should attempt to compose an image that conveys the "essence" of water, what it is (liquid), how is looks, feels, tastes, behaves (flows), the role it plays in life, or some other meaning or characteristic associated with water. You might find it useful to reference the "Fluid" (http://community.spiritofphotography.com/index.php?topic=644.0) assignment. That assignment dealt with the use of specific techniques to convey the "fluid" nature of a liquid. In the fluid assignment we talked briefly about how the surface tension of a liquid causes the distinctive "rounded" shapes, and how we could use soft light (and control the direction of the light) to provide modeling of the three dimensional, rounded forms and convey the fluid nature of a liquid.
(http://spiritofphotography.com/coppermine/albums/userpics/10001/20091009_094728_v3.jpg)
The fluid assignment also mentioned the use of a slow shutter speed to create a soft motion blur and convey a sense of the movement or flow of the liquid. One common question is "how slow does my shutter speed need to be." And of course as is often the case with photography, the answer is "it depends." :) It depends most on how fast the water is flowing, but can also depend on how close you are to the water (how much magnification your lens is providing, or how quickly the water is moving across the frame.) It also depends on what "mood" or look you are trying to create. Slower shutter speeds will result in a softer, dreamier looking scene, whereas faster shutter speeds will convey more of the "dynamic" or powerful nature of water. In the scene above my shutter speed was 1/15 sec., while in the scene below, in which I wanted to convey more of the pulsing power of the water, the shutter speed is 1/125 sec.
(http://spiritofphotography.com/coppermine/albums/userpics/10001/20100930_10442890.jpg)
In general, shutter speeds in the 1/8 to 1/15 second range will convey the most pleasing sense of motion when photographing water. Slower shutter speeds will create that "cotton candy" or soft etherial look you begin to see in the images below.
(http://spiritofphotography.com/coppermine/albums/userpics/10001/GD8W8303_crop_2%7E0.jpg)
f16, 1/3 sec, ISO 160
In the image above, the slower shutter speed helped to accentuate the flow of the water by filling in some of the areas where only small amounts of water were flowing at any one time. By extending the time, we create the appearance of more flow.
(http://spiritofphotography.com/coppermine/albums/userpics/10001/GD8W8358%7E0.jpg)
f19, 15 sec (ISO 6)
When photographing water we also need to be careful that we don't overexpose areas of the water. Overexposing areas of the water will result in a white featureless blob, instead of conveying the fluid sense of flow and motion that we are striving for. You should chose the brightest areas where you want to retain visible detail and then spot meter to expose these areas as Zone VII (+2 on your exposure meter). (Please see the Zone VII assignment (http://community.spiritofphotography.com/index.php?topic=511.0) for more detail on exposing for Zone VII.) In the images above, there are still a few small "hot spots" that are overexposed. I tried to minimize these hot spots as much as possible by waiting for shade to cover most of the stream. Ideally, waterfall images should be taken in cloudy or overcast light, which will help control the contrast and minimize hot spots.
The assignment for the week of 11 - 17 July 2011 is "Water." Please upload your images to the Water album in the weekly assignments category of the gallery no-later-than midnight, Mountain time (GMT -07:00) on Sunday, 17 July 2011. I'll look forward to seeing your images.
Keith