Originally posted by slr_neophyte Many have referred to in this post "the lens's sweet spot." While I have an idea of what it means, what exactly does it mean, and how does a person determine this for each lens they use? Is there a chart somewhere, or a database one could look at?
Thanks,
Jordan
You will have to experiment with your equipment. Optics are an analog entity in a digital world. And you can look up reviews on specific lenses.
As a general rule:
If you are trying to isolate a subject with a shallow depth of field, use a wide lens aperture, 1.4 to about 5.6
If you are trying to show a foreground, middle and background with great depth of field, use the smallest apertures, 16, 22, 32.
If your subject is in one plane, like the moon 239,000 miles away, and you want the sharpest possible picture, most lenses are best stopped down 2 or 3 stops, about f8 to f11, aka "the sweet spot".
You still need to focus well. Some lenses are so good, they are also very sharp,wide open. They are generally more expensive. The Pentax 50-135 is one. The Sigma 100-300/4 is another.