User:Jameslwoodward/Architectural photography

Architectural photography is among the most difficult of photographic areas. This is an attempt to clarify some of the issues and help my colleagues who take photos of NRHP sites to take better photos.

Perspective
Architectural drawings and photos are inconsistent in their use of perspective. We generally expect that horizontal lines will come together in the distance at a vanishing point. We do not, however, want the vertical lines to come together even though the top of a building is usually farther from the eye than the bottom and therefore "should" vanish. The reason is simple, if the vertical lines are not parallel, then the building appears to fall over backward. Perugino knew this, so that while the squares on his plaza converge, the sides of his buildings do not.

This gives architectural photographers a problem. You can achieve the "proper" perspective only by keeping the film plane exactly vertical. Assuming you have a wide enough lens to get the whole building on the film, this will leave you with 40-45% of the image, sometimes more, below the building. View, field, and press cameras can avoid this by raising the lens and, in view and field cameras, lowering the film. Some professional grade 35mm cameras, including Nikon, Olympus, and Canon have perspective control lenses available which can be raised. Using a modern digital point and shoot, you have little choice but to crop off the bottom of the image after you upload it into a computer.

Another advantage of interchangeable lenses is that usually the widest angle lens available is much wider than the widest angle you have on the zoom lens of a point and shoot. While no lens in existence will allow you to take a picture of a ten story building from across a narrow street, a wider lens will often help.

Barrel distortion
Almost all production wide angle lenses suffer from barrel distortion -- a tendency to render rectangles that are away from the center of the image as barrels. The reason is that lens designers have many conflicting goals, including low weight, high speed, correct color, sharpness, cost, and so forth. Since barrel distortion is very hard to see in most consumer photographs -- portraits and groups, landscapes, pets, sports -- and expensive to correct, it's usually at the bottom of the list.
 * It's more pronounced in cheap lenses
 * It's much more pronounced in zoom lenses
 * It's much more pronounced at the edges

Exposure
The modern point and shoot camera does a very good job with exposure, but there are times when it needs a little help. If you're shooting into the sun -- the shady side of a building -- and there's a lot of sky in the image -- you can usually help your camera by telling it where to take the exposure reading. On many point and shoots this is as simple as pointing the camera at the shaded part and pressing the shutter release halfway down. Then repoint the camera at the image you actually want, and shoot.

Tips

 * Pay attention to back-lit subjects, help your camera by locking the exposure on the right place.
 * Get as high as you can. Carrying a step ladder helps.
 * Keep the film vertical if you possibly can. Crop the bottom off.
 * Pick out a spot on the building that is at the same height as your lens and aim at it. It's hard to keep the camera actually level unless you really pay attention. It will often feel as if you're pointing the camera down.
 * Keep towers in the center.
 * Crop curved street light poles at the edges.
 * Use the screen, not the optical viewfinder. Most consumer cameras take an image around 10% larger than the view through the viewfinder, so you're giving away width and height when you use it.  If you find the screen hard to see in the sunlight, carry a piece of black cloth -- I have one left over from my view camera days, complete with weights in the corners, but nothing fancy is required.