| A camera lens is made up of several elements, | | | | frame, but any stray light just outside it can |
| pieces of special glass ground to a specific curve | | | | cause an obvious effect. Efficient modern |
| according to computer calculations. Each element | | | | anti-reflective coatings are great, but they will not |
| directs light in a particular way and corrects | | | | stop all flare. |
| aberrations caused by other lens elements. A | | | | Any precautions in using a lens hood? |
| telephoto lens may have from 10 elements up to | | | | Mainly, be careful they don't appear in the picture. |
| double that number. | | | | Zoom lenses give more problems than fixed focal |
| Usually, elements are joined together with optically | | | | length lenses, because as the angle of view |
| clear cement in groups. Rare earth components | | | | widens, the chance of getting the edge of the |
| and minerals are used to make each element | | | | hood in the picture is greater. Therefore the |
| perform its task efficiently, and these elements | | | | supplied lens hood with a zoom lens is designed |
| are coated with high quality anti-reflective | | | | for the widest angle of view. As you switch to a |
| coatings. It's a highly complex and expensive | | | | longer focal length the use of an extended hood is |
| process, yet in spite of all the research the | | | | possible. Of the round and petal shapes, petal |
| perfect lens has to date not been made. | | | | shapes are better because the hood is designed |
| So if it's all high tech, why is there a problem? | | | | to match the oblong shape of the sensor. |
| If a very bright light from outside the subject hits | | | | When is flare acceptable? |
| the glass, the reflections can cause a range of | | | | Artistic effects such as creating drama, a feeling |
| major image problems. These include washed out | | | | of realism, in a silhouette, are all possible subjects |
| color, loss of contrast, bright shapes in the image, | | | | where flare could help. Bright rays shining through |
| often polygonal, the shape of the diaphragm. It's | | | | trees, the early morning feeling, is an example of |
| not unusual to see bright streaks as well. The | | | | the so called veiling flare. This washes out color |
| name for these problems is flare, which can | | | | and contrast too, but adds to the impression. |
| occupy a large portion of the image area. Because | | | | A word of warning. Use manual focus and |
| flare is much brighter than the subject it tends to | | | | experiment. Auto focus tends to latch onto the |
| pull the viewer's eye toward it, losing the impact | | | | brightest part of the subject, which won't be your |
| of the picture. | | | | intention with this kind of photography. You will |
| How can I stop flare? | | | | need to look at the result to see if you're getting |
| Make sure the lens is shielded from bright light | | | | the effects you want. |
| outside the picture area striking the front element. | | | | What do you suggest? |
| Ways to do this include using the black hood that | | | | Everything depends on your original intention and |
| came with your lens. This fits over the front and | | | | perception, as in all creative work, as to whether |
| provides a protective barrier. No hood? Use your | | | | the effects are good or bad. Used effectively, |
| hand (make sure it's not in the picture). A piece of | | | | flare is a good way of expressing a feeling of light |
| card (often called a 'flag' in this application) or | | | | and airiness, drama, morning, hope, |
| some object between the lens and the sun, a | | | | freedom,amongst others. The best way is to |
| tree, post or other object to avoid a direct hit on | | | | achieve it is to go try it. Get out of bed early. |
| the lens usually works. | | | | Meet the sunrise, find a subject, put the light just |
| Is the sun the only cause of flare? | | | | outside the viewfinder and experiment. You may |
| It's the most common one, but any source of | | | | surprise yourself. And if you miss it you can |
| bright light will do it. So you could get a street | | | | always add it in later in software. (But the real |
| light, car headlight, even the full moon in a night | | | | ones look better.) Happy shooting. |
| shot. The light source does not have to be in the | | | | |