On The Street - Shoot Manual
George L Smyth
Shooting manually is the sort of thing that most photographers no longer do, but need to reconsider. Since Kodak said "You Press The Button, We Do The Rest" in 1888, cameras have gotten easier and easier to use. Features like auto exposure and auto focus are so prevalent that their use now is simply expected. Indeed, it almost makes no sense to not use these conveniences ... unless you think carefully about it.
Allow me to make my case.
The camera has no idea what your intentions are when taking a picture. It may be able to somewhat guess the subject matter, as some software can recognize objects as faces, but how to render that subject matter is something that can only be done by the artist. A camera's determination of the exposure is generally a matter of looking at the range of tonal values and adjusting the settings to average and/or include most of them. Sophisticated matrixing systems can divide the field of view into segments for a more accurate assessment, but the idea is basically the same.
The question is whether or not the photographer wants to have their exposure placed in the middle of the available values. The blind acceptance of a camera's decision is most noticeable with pictures of snow, which have gained grey values because the camera's software decided that the luminosity of the snow was too bright. Chances are that the photographer may have wanted a more natural rendering, which would have required additional exposure to get the snow to display properly.
There is nothing inherently wrong with allowing a camera to make some decisions, but there is something wrong with allowing it to make creative decisions. Once you turn off auto exposure you are free to make your own creative choices.
Your first choice is the period of time that will be captured. Do you want people frozen or would you like to show movement? If the former, what is the shortest period of time that will allow this to happen? If the latter, how much blur are you seeking?
Your second choice is depth of field. Are you looking to pull one person from the background or should everything be equally sharp? If the former, what depth of field will allow this to happen? If the latter, what is the largest aperture that will allow everything to appear sharp.
Your third choice involves how you wish to render the scene. As the sun goes down do you want to make believe that this is not happening? You can do this by ensuring that your exposure stays right in the middle. Since this is the time when shadow details start to get lost you may decide that you want to dump them. This should be your decision, not the camera's.
Finally, with the advent of digital cameras you now have the choice of ISO for each frame. Setting your ISO to auto is a reasonable choice if the camera has the ability to avoid unwanted noise at its chosen setting. Some cameras allow one to specify the highest ISO to be automatically set, so testing your camera to see what ISO begins to offer unwanted noise is a good idea.
It seems odd that one might not want the camera to automatically decide where to focus. However, when it is time to take a shot you may wish your subject to be off center, and in doing so you may end up focusing on a distant object instead of your subject. Also, if the lens goes into seek mode there will be a lag, and if it does not find a focal point then the shot will be missed. This can all be taken care of by turning off auto focus and using the hyperfocal distance information for your camera.
In determining your exposure you have already selected your F stop, so now you need to match that with the depth of field it will allow, and set it to accommodate the likely location of your subject. As an example, when on the street I am probably not going to be photographing anyone closer than six feet from me and generally do not care about getting the distant background in focus. For my Fujifilm X100S I generally like to use f5.6 as my aperture (the camera employs a fixed 35mm equivalent lens), so by setting the focal length of the lens at ten feet I get about six feet to twenty-eight feet in focus, which is plenty. You need to make your own decision about your camera and lens.
Horror of Horrors
All of this means that you need to learn about your camera, but that should be a good thing. Employing this information will eventually become intuitive, and once you have real control over these choices then your images will become more yours, and less a collaborative effort with an unknown person who wrote the software for your camera.