Get Your FREE copy of Top 10 Tips for All Beginning Photographers ...plus Lightroom Develop Presets & Wedding Photography Checklist!
Keep Shooting! Photography Assignments (04 Feb 2013)
Be sure to check out the new Keep Shooting! Photography Assignments, every two weeks there is a new one!
I am not sure of what photo you are referring to but I think I can give a coherent answer to your question without it. Okay, so here we go.
With a wide angle lens, it is often not very important what aperture you use when shooting a wide scene. I am speaking in regard to the depth of field aspect of aperture here btw. This is because wide angles are so wide, everything will be pretty much in focus provided you are using a fast enough shutter speed and aren't sneezing when taking the shot. Therefore, the photographer here could use f/2.8 and still have everything pretty much in focus. I suspect he/she used f/2.8 here to get a shutter speed fast enough to hand hold the shot (i.e.: not use a tripod), and an ISO low enough to prevent noise in the shot.
I have never heard of f/12 or f/15 but f/11 and f/16 would also be possible here. You would use a tripod though because as you use a smaller aperture, the amount of light getting to the sensor is less and less, therefore the shutter speed would have to decrease (maybe into a few seconds.) And good luck holding the camera steady for a few seconds.
An example is here:
I used f/22 here because I liked the starbursts you get behind the bike in the shot and the way a 13 second exposure rendered the water. But you could have also shot this using a wider aperture and a faster shutter speed. I used a tripod.
Hope this answered the question.
Please Support Us