Actually it's a trick question because neither answer is correct for every type of environmental portrait. As a general rule, to allow a subject to occupy the same portion of the frame, you should either be close to the subject and use a short focal length, at a "moderate" distance with a normal focal length, or far from the subject with a long focal length. What constitutes a moderate distance depends on the size of the particular subject: the larger the subject the longer the moderate distance will be.
For environmental portraits, there's a twist to the general rule because there are now two elements: the subject and the background element.
My first step is to choose the relative sizes of the relevant elements. By relevant elements, I mean the part of the subject(s) and the part of the background that I want to include in the frame. For example, if the subject is just one person, I choose whether to do just a head shot or full-length or something in between.
Similarly, for backgrounds, I don't necessarily want to capture everything that I can see. If there's a mountain range I don't need to have the entire mountain range in the shot. Just capturing a portion of the range may be enough to imply the presence of a mountain range.
Let's talk about controlling the relative size. To make the background element smaller relative to the subject (or to include more of the background), I either move the camera closer to the subject or I move the subject farther from the background, or both. Vice-versa if I want the background element to look larger (or capture less of the background).
Once I have the relative sizes of the subject and background the way I want them, I use the general rule to determine the focal length to use.
A few weeks ago, we spent the weekend in Palm Desert. I first took a shot of my parents with a short focal length (28.5 mm in 35mm terms), from about 10 feet away.
|19mm (equivalent to 28mm), about 10 feet from subjects|
|50mm (equivalent to 75mm), about 20 feet from subjects|
A few months ago, we were visiting the charming town of Solvang near Santa Barbara. In this first shot, my wife was about 150 feet away from the windmill and my focal length was 50mm (75mm in 35mm terms).
|50mm (equivalent to 75mm)|
Another solution was to use a shorter focal length to capture a wider view that encompasses the group. However, if I did that from the same distance, the windmill would look much smaller. To make the shot work with a short focal length (25.5mm in 35mm terms), I asked the group to move much closer to the windmill (now about 75 feet away), keeping the windmill a prominent compositional element.
|17mm (equivalent to 25mm)|
Sometimes I have both options available: a short focal length close to the subject and background or a long focal length far from the subject and background, with about the same relative sizes. In that case, I consider other factors such as the depth of field or kind of perspective distortion I want.
If you found this post useful you may want to check out these related posts:
- What's the point of having different lenses? Controlling composition with different focal lengths
- Tip: Using a Zoom Lens as a Compositional Aid
- Getting a larger moon in the background