Most of my jobs include shooting in what appears to the camera as low light. For this reason I am nearly always experimenting with different exposure settings trying to keep the ISO as low as I can while still getting enough detail to reveal in developing.
That's a key element of much photography; knowing what you can capture in the digital depths of your sensor, unseen in the JPEG preview, that can be successfully revealed by your developing software.
The modern DSLR captures a ton of detail. This image was shot at ISO 1000 in very soft hotel lobby lighting.
Comments