Originally, photography involved glass (and then flexible film) negatives. The film came in various sizes and grades of light sensitivities. Once the film was exposed, it would be developed in a darkroom using a series of chemical baths. Then it would be dried and then placed inside a projector in order to make positive paper copies of the film negative.
Most professional photographers processed their own film, but writers and other media professionals often let others handle the processing.
The key question for a photographer was to set up a photo that would be in focus, and have sufficient light to show the subject.
Using an average type of film, a photographer would have to decide what aperture and shutter setting to use in order to take a good photo.
The aperture is the part of the lens that opens and closes, like an iris, to let in more or less light. The smaller the aperture, the less light, but the better the focus.
The shutter is in the camera body and can be set to a variety of speeds. (From 1/1000th of a second to 1/125th of a second, most action can be caught without blurring. But at 1/60th of a second, or longer, the photo will blur if it is not on a tripod simply due to the shaking of the photographer’s hands.)
The big deal was to not have your shutter too slow, or the action would get blurry, or to have your aperture too open, or the subject might not be within the depth of field.
So, let’s take two cases:
1. Basketball game — Light is not very bright, can’t use a flash, and action is swift. Probably need a fast shutter, and that means you have to open up your aperture. In that case, you have to be very careful of your focus; using a single lens reflex (SLR) film camera, you might have to constantly focus on the players as you follow them on the court.
2. Track meet — Outdoors, bright light, action is also swift, so you need a fast shutter but you also have to close up the aperture. In this case, the depth of field of your focus is very large, and you should be able to keep most of the field in focus for most of the time.
Digital Cameras — You dont need to specify aperture and shutter settings like the old days, but you may need to decide on AP or SP (aperture priority or shutter priority). How would that work for cases 1 and 2 above? SP means you will have a fast shutter. AP means you will have a larger depth of field.
- Why might you prefer a fast shutter speed? (In digital cameras, SP for shutter priority)
- Why might you prefer a small aperture? (In digital cameras, AP for aperture priority).
Digital file sizes
The old 35 mm film cameras had negatives coated with silver iodide that contained the rough equivalent of 12 million pixels of information, or about 12 MB. Today standard moderate quality professional cameras have 12 to 24 MB photos.
Digital files can be downloaded from the camera to the computer in a variety of ways: Cable connection, memory card or internet uploads. Cameras that give you the option of automatically uploading photos usually send a web-sized version of your shot that is far smaller than the original still on the camera. You may wish to save the larger versions on the memory card along with the smaller uploads.
How to shoot the moon. (Portland Oregonian)
Depth of Field (About.com)