NB: This series of posts will convey my understanding of photographic exposures. While I hope it serves a useful purpose, I by no means describe this series as a be-all, end-all resource on exposure. As ever, if you feel I have made a factual error, please correct me.
Exposure is a combination of how long and how much light an imager (digital sensor or film) is exposed to by the lens and shutter. ISO/ASA (and less commonly nowadays DIN) is the standardised measure of an imager’s light sensitivity (i.e. sensitivity dictates how much light and how long for). In Part Four of this series, I shall attempt to integrate these three elements.
Sitting down to write this, the phrase “personal preference” is coursing wildly through my mind. At the end of the day, the way in which you expose a photograph is as much a reflection of your thoughts as the composition. In fact, when you consider that depth of field, noise/grain and depiction of movement are directly related to your chosen exposure, I posit that composition itself hangs upon a well-chosen exposure.
As well as the aforementioned factors, there are, broadly speaking, three exposure levels: under- (deeper shadows and more detailed highlights), “normal-” (evenly balanced shadows and highlights) and over-exposure (lighter shadows and less detailed highlights). These are useful for changing or setting a mood, such as under-exposing for a moodier atmosphere, or over-exposing for a much happier one.
Rather than exploiting my typical verbosity, I think I’ll let my pictures (and their captions) do the explaining this week. There are justifications for choosing just about any exposure in any circumstance, so the best advice I can give is to try out the different settings, and experience how they change the way you depict things. You may find you prefer particular styles for particular subjects, or, that your choices vary depending on your mood or the weather. It’s not untoward to use several different sorts of exposure between successive photos at all.
To summarise, each element of exposure affects the way your image depicts the subject. You can use these elements in combination to craft your image in the way you see fit. Personal preference in the creation of the image is what makes it yours. If there is anything you want to ask about, feel free to e-mail or comment, and I’ll reply as promptly as possible.