Blind Fool wrote in post #17877630
I'm still fairly new to photography and thought I needed f/14 there abouts for the depth of field to keep everything sharp..
Ultrawide is useful not just for it's field of view, but also, for how depth of field is calculated.
Here's a helpful calculator to help put it into perspective: LINK.
I like to basically use this to get an idea for various focal lengths (I just round and generalize them) so I know what the maximum aperture should be, for appropriate depth of field to keep the horizon reasonably sharp.
If you put in the calculation for an APS-C sensor, 11mm focal length, F5.6 with a subject distance of 4 feet, you'll get 2 feet to infinity in focus basically. F8 gets you even closer in focus to the foreground.
I use things like that so I know about what aperture I have as an option.
When it comes to long exposure, aperture can be further stopped down to gain time.
But it's a handy way to have a quick knowledge of effective working distance and aperture for depth of field, while considering best image quality at a lens's best aperture for sharpness and performance, etc. It's probably closer to F8~F11.