Digital Outback Photo
- Photography using Digital SLRs

Digital Camera Experiments #001


Multiple Exposures for Moving Water

essay by Brad Hinkel (2/21/2005)


Image 1 – Experiments with Mixed Visible and UV Light

Digital Camera Experiments (Intro to the series)

I love digital photography – I started shooting a digital camera back in the days when ½ megapixel was standard; and the resulting images looked fuzzy even on a computer screen. But even these early digital cameras changed the way I was able to shoot in the field and easily process the results in the digital darkroom, giving me many new options for creating images; and the current technology now allows me to create excellent images while retaining these options. The advantages of digital photography go well beyond the current debates of resolution into the realms of experimentation and creativity.

This article is the first in a new series of articles on many of the ways that I have learned to work differently when using a digital camera and a digital darkroom. Many of the topics will focus on experimentation with a digital camera and shooting digital multiple exposures, but I will leave myself the option to discuss some other random topics that relate to the changing world of photography. I’d like these articles to have two major objectives. First, these articles should challenge the way you think about shooting images in the field, I’d like to imagine new possibilities and try to create new ideas for images. Frankly, I think that realism in photography is a bit overrated and over emphasized, but some of my experiments may improve the apparent realism of photography; today’s article on shooting moving water is one example. And secondly, I’d like these articles to provide some ideas for getting out and shooting images; the most important step to creating good photography is shooting, shooting, and more shooting. I strongly suggest that the best photographers in the world have all shot the most bad images; thousands upon thousands of bad images intersperse with some wonderful gems. So hopefully these articles will be an incentive to shoot.

So one of the first major advantages of digital cameras is “Experimentation”. I’ve heard a number of photographers claim disdain for the preview screen on the back of most digital cameras. This screen provides a low resolution view of the image captured by the digital camera and often it also provides a histogram of the image as well. I think the disdain comes partly from the view that ‘good’ photographers can get the exact exposure correctly without using such a tool, or that the preview is so small and imprecise. In my articles, I’d like to show some example of how I use the preview screen and histogram to create some image that would otherwise have been much more difficult using film.

I can think of lots of example of experimentation that I was taught in my photography classes; shooting long exposures, panning, shooting while focusing, or shooting while zooming. After one class on experimentation, I ran out and shot a couple rolls trying every possible combination of experiments. The results were interesting, but all of the slides ended up in the circular file. These experiments were good ideas, but no amount of bracketing could help me figure out the perfect technique as I was shooting these frames. But now, with a digital camera, I can get almost instant feedback to fine tune my image on-site. I can now create some interesting image while experimenting in the field, and its fun.

And another major advantage of digital cameras is the ability to quickly and easily shoot multiple exposures, bring these into the digital darkroom, and combine these into a final compelling image which better fits the vision of the photographer. A simple example for this is shooting panoramas – making a series of slightly overlapping images that can be pasted together to create one larger final image. There are a whole range of additional possibilities for making multiple exposures by making minor adjustments to the different images as you shoot each. I write articles that list some examples of these combinations.

Making multiple exposures in the field allows you to capture a wider range of information than might be possible with a single exposure; plus these multiple exposures can be combined together relatively easily since the basic components of light in the scene are relatively unchanged. In general, you change just one aspect of the image; time, focus, exposure, etc; and leave all the other elements unaltered. This first article will cover combining two images shot at different shutter speeds to create a realistic image of moving water.

Image 2 – Blending Images of Moving Water

Digital Camera Experiments:#001 Multiple Exposures for Moving Water

Moving water is magical – the never ceasing flow of a water fall, the never quite still surface of a lake, the never quite identical pattern of waves – these motions mesmerize me and continue to draw me back to photographing water. Yet, what are the best options for representing moving water on a static image.

The basic ‘rule’ for photographing water suggests photographing moving water at fairly long to very long exposures (¼ sec to 10 sec) to produce a silky smooth blanket of moving water. I have also made many images of moving water with very short exposures (1/250th sec or shorter) – these freeze the action of water to look like acrylic sculptures, but maintain the tension of motion. Ironically, the exposures of moving water that I have liked the least are near the ‘presumptive’ speed of the human eye; around 1/30th sec – these often just look blurry.

Over the last few years, I have used digital techniques to create multiple exposures of moving water that can be combined together to create a new look for moving water.
In its simplest form, I merely make one exposure at around 1/250th of a second (this requires a fast lens and good light), and make a second exposure at around 1 second or longer (this requires a small aperture, a neutral density filter, and a tripod). I always take both these images on a tripod so that they are sharp and very easy to register over the top of one another. I then overlay these images in Photoshop and experiment with various blending options for combining the sharp and blurry images together.

Image 3 – Example of Blending Two Shutter Speeds

Blending is easy, move the two image over the top of one another (just copy one image over the other using the Duplicate Layer command, but duplicate it to the second image – if the two images were shot on a tripod, they will be in exact registration over one another). Then change the opacity of the upper layer. Or you can change its blending mode – I have had good luck using the ‘Overlay’ blending mode, since it will mask where the upper layer is grey, but show details where it is bright or dark. It’s that simple – yet the results create yet another interesting options for photographing moving water – in fact, the combination of long and short exposures produces one of the most realistic and still pleasing images of water. I have also experimented with locally blending in sharp water detail (from the 250/th sec exposure) by masking out part of the sharp image – and have mixed sharp and long exposures using flash.

Experiment and you might be surprise with the results.

Image 4 – Example of Mixing Two Shutter Speeds


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