Used to be you thought of aperture as way to control light AND depth of field while you thought of shutter speed as controlling light AND the ability to stop or blur motion.
Of course, these things are still true today. However, with the rise of digital camera sensors with ISO ranges all the way up to 102,400, you can almost think of the three basic camera functions as each focusing on only one function each: aperture/DOF, shutter speed/motion freeze or blur, and ISO/light gathering.
If you ever wished to have the whole gamut of depth of field control under any lighting conditions, well, we are nearly there. Before long, a noiseless,, tack-sharp image will be possible in nearly complete darkness, if the sensitivity of sensors continues on course. And then the still photographer will never have to sacrifice any creative control of his imagery, except where it concerns uncooperative subjects! And I’m sure we will soon perfect mind-control for that.
Of course, utilizing the aperture range and investing in quality, fast glass will continue to be wise decisions, but high ISO (with acceptable digital noise) can and will, all by itself, open doors to photographic control and creative freedom that have never been seen before.
Now, how do we eliminate all that pecky noise? I’m sure it’s only a clever software algorithm away! Stay-tuned….