Shooting The Rapids
Although it was an overcast morning when I was photographing these rapids, an HDR was necessary to capture the whole dynamic range of the scene. Of course an overcast sky is easy to blow out but you’ll find that whitewater reflects so much light that it’s often completely blown out also. Or, if you’re letting your camera choose your exposure and your subject is anything other than the whitewater, your subject will likely be way underexposed. There are still a few tiny portions of my image which are blown out but it wasn’t my goal to prevent that — it was just to present the image in a way which more represented what the eye could see as opposed to what the camera could capture in a single frame.
Note that this image was shot at ISO 320. There’s nothing magical about 320 per se but when you’re shooting fast-moving water, you’ll find a certain shutter speed which gives the “look” you want. If you’re shutter speed is too long, the water is simply a blur. If it’s too short, you lose some sense of the motion. Of course freezing motion or completely blurred water may very well be the “look” you want but in this case I wanted somewhere in the middle. I chose f/11 as my aperture because it’s in the sweet spot of the lens yet gives reasonable depth of field when the focus distance is relatively long. With the aperture fixed, ISO became my main lever for setting the range of shutter speeds I’d capture in my brackets. I shot brackets from ISO 100 up to 1600 and chose this ISO 320 value for the final image based on how the water looked. This allowed me to keep some detail in the water such as what you see in the water pouring over the smallish rock outcropping near the center of the image.