For every image there probably is an ideal sweet spot, where an image can be captured. However, it depends on a variety of things.
- Light - or lack of light - This is going to change for each image opportunity. What is good in the afternoon will not work at night, etc. You have to adjust to the available light at the moment, or add some from some source.
So, how do you do that. Well, for the light available, and the gear that you have, I would put forth the following:
- P mode - The camera determines the optimal settings, based on the environment that it sees, and takes the image.
Or
- I use Av mode, with the ISO at 80, and the aperture at f8 (i.e., Norm's example, or what I remember being the sharpest f stop for the lens), then....
If there is not enough light, I then....
- Increase the ISO to about 1600 and if there is still not enough light (maintaining a reasonably fast shutter speed)
- Increase the aperture from f8 to what ever the lens allows - f2.8 and if there is still not enough light (maintaining a reasonably fast shutter speed)
- I might actually switch lenses to a faster lens, if I have it with me (31Ltd at f1.8)
- Increase the ISO beyond 1600 till there is, always trying to keep the shutter speed fast enough for hand holding - 1/(2*focal length).
If there still is not enough light, then break out the tripod (which is usually the case, because I shoot at night). Actually, I start off with the tripod, since I know that there is not enough light...