Last year I decided to use the URL "idealfstop.com" to set up my website. So I guess its time to start talking about "what is an ideal f-stop?" There are at least two answers to this question. From the creative perspective, the ideal f-stop is whatever you think is best. But I'm not interested in that discussion. Rather, I think its useful to understand the technical answer to the question.
Every lens we have in our bag has a "sweet spot" - the point at which the lens is the sharpest. It almost never occurs with the lens aperture wide open, but rather when it is stopped down a bit. For each lens, this will be a different setting. Some lenses are incredibly sharp at f2.8, while others need to go to f8.0 to reach their peak. Wouldn't it be useful to know this information about each of your lenses?
As a fairly lazy photographer, I just don't feel like doing the complex lens tests to figure all of this out. Maybe someday and when I'm old, fat and unemployed I will do this; but right now. I just want some quick answers. So I visited one of the better websites for lens reviews, took their data and made a short list of my lenses and their ideal f-stops. If you are interested in doing the same, I highly encourage a visit to www.photozone.de.
Here are the results for the lenses in my bag:
|Sigma 20mm/f 1.8||8|
|Canon 24-105mm IS / f4.0||5.6|
|Canon 50mm / f1.4||2.8 - 4.0|
|Canon 85mm / f1.2||2.8 - 5.6|
|Canon 200mm / f2.8||5.6|