| To capture clear images, high-quality cameras | | | | extend depth of field, while larger apertures |
| generally use lenses that require manual or | | | | reduce it. To ensure the fixed-focus lens maintains |
| automatic focusing. Unless the lens is focused | | | | proper focus, camera makers have to use small |
| correctly, the subject will appear soft and blurry. | | | | apertures to create a wide depth-of-field area. |
| In contrast, the majority of simple cameras, | | | | This, in turn reduces the light falling on the sensor. |
| including cell-phones, disposable and inexpensive | | | | In bright sunlight, this is not an issue, but when the |
| snap-shot cameras use a fixed-focus lens that | | | | light becomes dim, a focus free lens cannot |
| does not need to be focused. Fixed-focus lenses, | | | | record well-exposed images without boosting the |
| also known as focus-free lenses, are designed to | | | | ISO into an unacceptable range. |
| render everything in a scene in focus. | | | | No close focusing |
| Fixed-focus lenses are not the same thing as | | | | Finally, most fixed-focus lenses are calibrated to |
| auto-focus lenses. The automatic mechanism of | | | | what is known as the hyperfocal distance. This is |
| an auto-focus lens still must adjust the lens to | | | | a photographic concept that establishes the |
| achieve maximum sharpness. A fixed-focus lens, | | | | closest distance to the lens that objects can |
| on the other hand, never needs to be adjusted to | | | | remain in focus, while still maintaining sharpness at |
| deliver sharp images. | | | | infinity. When a focus-free lens is set up in this |
| At first, this seems odd. Users of low-cost | | | | way, everything from half the hyperfocal distance |
| cameras have no need to be concerned with | | | | to infinity will appear in focus. |
| focusing, while those who have invested | | | | While the hyperfocal distance creates a deep area |
| substantial amounts of cash in a high-quality | | | | of focus within a photograph, it also prevents the |
| camera system have to take focusing in | | | | camera from focusing at close distances. With the |
| consideration on every shot. | | | | exception of some telephoto lenses, most dSLRs |
| There are several reasons why you will not find | | | | and high-quality range-finders can capture images |
| fixed-focus lenses on top-quality cameras. It is not | | | | at distances of two feet or less. The typical |
| an issue of lens quality, as many fixed-focus | | | | focus-free lens cannot accurately capture |
| lenses have very good optics. | | | | subjects nearer than six to eight feet from the |
| Striving for depth-of-field | | | | camera. |
| Focus-free lenses accomplish their magic by | | | | The combination of wide-angle optics and and the |
| relying on depth-of-field and wide-angle optics. | | | | lack of close focusing capabilities means that the |
| Depth-of-field is the photographic term for the | | | | photographer often cannot fill the frame with the |
| area in a photo that is in true focus. Wide angle | | | | subject. Portraits can be problematic, because the |
| lenses generally produce a wide area of | | | | fixed-focus lens cannot get get close enough to |
| sharpness, while telephotos almost always reduce | | | | capture a nice head shot. These optics can do a |
| depth-of-field to a minimum. Because fixed-focus | | | | credible job on landscapes and other far away |
| lenses require great amounts of depth-of-field, | | | | subjects, but they are useless at close range. |
| there are few, if any, focus-free telephotos. | | | | Despite the drawbacks, a focus-free lens is well |
| Lens aperture also contributes to the | | | | suited to unsophisticated, no-frills photography. |
| depth-of-field in a photo. The term aperture | | | | Fixed-focus optics can be used by anyone, |
| refers to the opening in the lens that allows light | | | | especially casual and easy-going snap-shooters. |
| to pass through to the sensor. Obviously, large | | | | They are excellent for training children the basics |
| apertures pass more light, while small apertures | | | | of photography. At the same time, a creative |
| reduce the light reaching the sensor. | | | | photo craftsman can produce wonderful images |
| Fixed-focus lenses require small apertures | | | | with a focus-free lens. There is an oft-repeated |
| In addition to regulating the amount of light | | | | mantra that great photos reflect the skill of the |
| passing through the lens, the aperture opening | | | | photographer, not the price of the camera. The |
| also controls depth-of-field. Smaller openings | | | | same thing can be said about lenses. |