While I have worked with digital cameras with increasing focus since 2003, I almost always use them at their lowest ISO setting, preferring to have the highest image quality possible, and willing to accept the lower shutter speeds that frequently come with such a setting. The higher the ISO setting, the faster an exposure can be made in the same lighting conditions. While I have made tests with higher ISO settings, I have never put these settings into use during a session, primarily because I had no need too.
For this session, however, the day had finally arrived when I
would need to push every last ounce of light sensitivity from my Nikon
D70. Miranda and I had planned to work in the shower of her new
apartment since she had moved in and had blocked out an hour on the last
afternoon of my stay in Halifax to make the images. The day, however,
had dawned with the sky a dark shade of gray and a torrent of water
lashed the streets and buildings of Halifax. The light in the bathroom
was very low, both due to the poor weather outside, and the dark colour
of the walls and floor. All the same, Miranda was still keen to model,
so after setting the camera to its highest ISO (1600, eight times more
sensitive to light than the lowest ISO of 200), we began to work.
I had expected, the light was incredibly low, necessitating exposures
in the realm of 1/15 to 1/8 of a second; not long enough to blur Miranda
if she stood still with care, but certainly enough to cause a problem
if I'd been been forced to use a shutter speed eight times longer
(leading to exposures of 1/2 to 1 second). Fortunately, the other parts
of the process fell into place perfectly, with the light from the
window giving some beautiful description to Miranda's body, and lighting
up the otherwise ugly plastic shower curtain until it became a
beautiful element to the image, as opposed to an annoying distraction.
In the end, the higher ISO did not detract as much from the final images as I had worried it would; even without using noise-reduction software, the image looked good at 7"x10" (the largest size the Nikon D70 prints to without making up the image resolution in software), and with care could easily go to twice that size without too many problems. I still would prefer to work at lower ISOs when possible, but with this experience under my belt, in a pinch I know that I can push the envelope a little further.