Depth of Field Scale
Look at the scale on the right. On most slr camera lenses there will be a similar scale found on the barrel of the lens. Unfortunately, many of the newer lenses do not have a scale on them. This scale is an invaluable tool for the photographer and if your lens does have one I suggest spending some time learning how to use it.
The words are added as labels and do not appear on the lens. The diamond marks the setting of the aperture and gives the reference point for calculating distances using the scale. For those who do not know, the sideways 8 represents infinity. The symbol comes from the mobius band or strip, which has no beginning and no end.
For the rest of the lesson, use the example graphic above in order to follow along. What does the scale tell us? Let's read the rings from the bottom going up. The aperture ring tells us the range of apertures available with this lens. It also tells us the aperture that the camera is set on, marked by the diamond on the depth of field ring. The next two sets of markings give us the distances at which our subject will be in focus with this lens at this setting. By turning the focusing ring, you can preset the focusing distance. It also tells us how far away the subject is once we have focused the lens through the viewfinder and the scale can be read in order to insure adequate depth of field.
Let's take a closer look at the depth of field scale. The f-stop numbers are marked from the diamond out extending in both directions. Notice that there are two f4 markings, two f8 markings, etc. In order to save space, the manufacturers sometimes use lines in place of each marking. Notice that the above scale leaves out f5.6 and f11. These f-stops are represented by lines only. Also, notice that f2.8 and f2 are not marked. This is because at these large apertures, focusing is critical and must be done visually through the lens. The margin for error is very,
Latest Articles