Depth of field is a powerful tool that we must take full use of every time we step behind the camera. The relationship between the subject and the other elements in the photograph is key to telling the story and either maximizing or minimizing the amount of information we see by changing the depth of field is how we bring out that story to the fullest. But it’s not always easy to get used to changing your F-Stop and then to think about that relationship between the F-Stop and the story.
A really good way to challenge yourself is to pick a good area where there is lots to work with, grab one camera body and one lens and one F-Stop. Practice. Watch the relationship between the subject, the background and the light and what the differences are with that one F-Stop. I just did this because I needed to practice so I grabbed the Nikon D5, 85 f/1.8 and shot at 1.8 the whole time I was out walking around. That’s how you get better. You do these little challenges and learn from the results.
So here is a real basic but important truth to using that shallow depth of field. First off it vignettes which can be good or bad depending on what you are trying to say but I tend to like vignettes because it sucks the viewers eye into the photo. The real lesson here is the focal plane. Everything on the same focal plane will be sharp so if you’re shooting at 1.8 but everything is on the same focal plane then you aren’t really going to make use of that shallow depth of field. This is why you need to stay at a slight angle. I put up these two images to show just that since they were taken with the exact same setup.