Exposure without giving up artistic controlphotography
Published on January 2, 2020
This article is about getting perfect exposure without giving up any artistic control on modern digital cameras. I assume that you already know about the exposure triangle: aperture, shutter speed, and ISO. I’m not going to explain what these parameters mean—there are already enough posts and videos about that. Instead, I will share my approach for setting the three parameters.
I always shoot in the manual mode, but with ISO set to auto. While aperture and shutter speed often can be used for artistic purposes, ISO value for a good exposure is something that is easily deducible given the other two parameters and the amount of light you have. Your camera can set ISO for you—tweaking it manually is a waste of time. In addition to that, auto ISO will automatically take care of minor changes in light, e.g. if you’re shooting outdoors.
It is important to understand that we want the lowest ISO possible in all our shots—ideally it should be always between 100 and 2000. High ISO will cause your photos to look grainy. We’re talking not about that that nice film grain, but about nasty digital grain which many people find much less aesthetically pleasing. Few people know that high ISO will also make digital cameras use lower saturation. This is done to reduce chroma noise. You don’t want that either. High ISO is justified only when you can’t improve the light and the question is “whether or not I get any usable photos at all”?
Aperture is the most important parameter because it contributes directly to your composition. So it is the first thing to get right. My algorithm is this:
Q: do we work in dim light and/or want to freeze moving subjects?
- A: yes. Depending on the light you might prefer widest apertures to keep ISO lower. High ISO is worse than minor lack of sharpness, vingetting, and loss of contrast most lenses suffer from when they are wide open, so go wide if it is necessary to let enough light in.
A: no. Q: do we want bokeh and/or shallow depth of field (striking
separation of in-focus/out-of-focus areas)? This often makes sense only
when you are close enough to your subject because bokeh also depends a
lot of the difference in distance between the object in focus and the
background. Trying to go for bokeh and shallow depth of field when you
can’t really get the effect is pointless. Nevertheless, sometimes I like
the intimacy of wide open lenses which comes from vingetting and the
other optical “imperfections”.
- A: yes. Go for wide apertures, perhaps widest, if you want maximum of that effect. Also keep it mind that sometimes you want to close your aperture just as much as to make your subject in focus fully, not partially as it happens with widest apertures. Use preview of depth of field on your camera to get this right.
- A: no. Set aperture a couple stops down from the maximum. At this aperture almost all lenses are sharp and constrasty. Go down if you want to increase the depth of field or to compensate for slower shutter speed (e.g. when shooting water in motion). I never go lower than f/10 since all lenses start to be soft at narrow apertures because of diffraction. If I want longer exposures I use a tripod and ND filter instead.
I find myself shooting a lot either wide open or at something between f/4 and f/8.
If you set ISO to auto and figured out aperture, shutter speed is easy:
Q: do we want to freeze motion?
- A: yes. Set shutter speed fast enough to accomplish what you want.
- A: no. Adjust your shutter speed till the exposure meter points at 0 with ISO being set at something about 100. If you have image stabilization (Canon terminology, IS) or vibration reduction (Nikon terminology, VR) you can use slower shutter speeds, depending on your focal length and how close you are to your subject. If you have a tripod, there is no point shooting with anything but ISO 100. Just make shutter speed slow enough to accumulate enough light.
This may look like a lot to keep in mind, but after practicing for a few months you set the right settings almost instinctively. I find the technical part of photography very easy with modern equipment. What is harder is to have an artistic vision.