Assignments

Each issue we'll devise an activity or assignment to provide some practice in an aspect of photography related to the feature article. We have two such activities here. On this page we suggest you find and shoot several examples of converging lines, and on the following page, we'll let you see for yourself the difference that even a limited amount of control can make to your images.

Find at least three examples of converging parallels—preferably both a vertical and a horizontal—somewhere in your general neighborhood. Buildings are always available, but try to find something else as well. Railroad tracks, power lines, fence posts—any repetitive form that is lined up at regular intervals will do nicely. [Download a worksheet with the following instructions.]

Objective: This activity is designed to provide experience in controlling the convergence of parallel lines and shapes. You can do this by (1) where you stand, (2) tilting or keeping the camera level, (3) changing the zoom or focal length of your lens, and by a combination of all three. In this assignment you will shoot from at least three places: very close, a medium distance, and way back.

The first step is to try is to exaggerate the convergence as much as possible. It is easiest to demonstrate this with a tall building, but it could also be done with a row of telephone poles, for example. We suggest you select a building—a church with a belfry or tower would be a good subject, but any structure 3 or more stories high will work fine. Here's the basic concept: the closer you are to your subject the greater the convergence and/or distortion.

Exaggerating the convergence:
Stand 10-12 feet from the base of the building about on the centerline of the structure and point your camera up. Adjust the zoom so the entire building (if possible) just fits in the viewfinder of your camera. You should orient the camera to create a vertical image, and be sure to get the top of the structure in the viewfinder. You may not be able to get the entire building in, even when zoomed out to the maximum, but don't be concerned about that—just be sure to get the top of the structure. If the building is generally symmetrical, the left side of your image should be very much like the right half.

Try several variations of that close-in shot. Move to a corner of the building and take another shot (although this one may not be as symmetrical), and then try it from the other corner.

Minimizing the convergence:
Now move across the street, or at least 60 feet from the building. Stand in a line with the center of the building and zoom in or out so the top of the building comes almost to the top of the viewfinder. Take two shots here: one where the building fills the viewfinder as much as possible. You may have to tilt the camera up, especially if its a very tall building. That's the first shot. For the second shot we want you to keep the camera level (this is extremely important) and zoom out until you can get the entire building in the viewfinder, even if it means that there is a lot of foreground in the viewfinder and the building does not fill the viewfinder. Keep the top of the building near the top of the viewfinder and take that shot.

When you think you have made those two exposures you are ready to move back to the third position, This location is not an arbitrary distance but back just far enough to to eliminate any remaining convergence. That will depend on your lens and the height of the structure, so move back as much as you need to. You may have to work at an angle that is off to the left or right of the centerline in order to get back far enough. That's OK, as long as you made a couple of pictures from close up and from a middle distance from a corner in line with this long distance shot.

If you have a wide-angle or telephoto lens and a few extra minutes you might want to shoot three more pictures with that lens, one at each of the positions.

Conclusion:
You probably noticed that the shape of the building in the more distant shots was much different than those you took when you were at a middle distance, and certainly vastly different than those taken up close. You can eliminate the converging lines of even the tallest structure if you get far enough away from it, but then you may need a long lens to get an image of reasonable size. Even a 80-210 mm lens, which is relatively common on today's digital cameras, will enable you to minimize convergence to quite an extent. Or, to produce a good undistorted image of the building, you may have to crop and enlarge one of your distant photos—there is likely to be an excess of foreground in the pictures you took from the longest distance unless you had a telephoto lens on the camera.

You don't have to print every image, but we suggest you print at least one from each distance and line them up side-by-side. That comparison will show you more than we could tell.

Select the most dramatic transformations—those may not be the shots you like the best, but ones where there is the most distortion. Then pay special attention to where you stood relative to the subject, which lens you used, and what your aperture setting was, as that will affect your depth-of-field.

                                                                                                    —FLG

If you would like to submit any of your images to the editors of this website, we'll select a few that illustrate the concept of converging parallels very well. One of our editors will probably make some comment--and we'll set up a means to enable others to do so as well on our Forums page (coming in a later issue).

No. 0 January 2006

 Photography is not simply a craft
   or art, but a means of seeing and
    thinking about our world.

Railroad tracks are a cliché, but that's no reason not to shoot them. Sometimes you want to point your camera towards the sun to maximize the reflection off the tracks. Be sure to keep your camera pointed down and use a lens hood. There may be times such as this where the photographer wanted to include the old RR station and a bridge, but the top quarter of the image might be cropped out, leaving us with quite a different image.

Shot for the assignment:

This was shot a few feet from the corner of the building. Notice how all the vertical edges of the building converge. Move your cursor over the image to see the verticals.

The photo above was taken from the street. One can see some convergence in the left corner of the building, but there is very little. If the building had been centered in the viewfinder, the camera would need to be tilted up, and that would have introduced some convergence.
      In the image below the photographer moved back another 30 feet and took a horizontal view. There is no noticeable vertical convergence. One needs to crop the foreground of course.