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You are hereHome > Tutorials > Learn > Exposure

Exposure

Correctly lighting your picture means avoiding under-exposed and over-exposed shots. I would venture to say that most shots taken by amateurs are under-exposed because the camera's exposure meter is fooled by stray light. What I mean by that is that your main subject is less lighted than the surrounding. The camera's exposure meter usually takes a weighted average of the light and adjusts the exposure accordingly. If the surrounding is much more lighted than your main subject, then the camera is "fooled" into believing there is too much light and an under-exposed picture results. If the surrounding is much less lighted than your main subject, the camera adjusts by letting in more light and an over-exposed picture results.

Professional cameras have spot metering to allow you to tell the camera exactly which part of your picture you want properly exposed. Most amateur cameras have adequate weighted average metering to compensate for the surrounding lighting so the above scenarios are rarely a problem these days. There are, however, still some situations that can fool your camera's exposure meter. Be aware of those situations and you'll be able to get correctly exposed pictures in situations where previously you couldn't -- or you might choose to break a few of the rules for some dramatic results.

Light and Shadows
The right balance and interplay of light and shadows create beautifully exposed pictures. With the improvement in metering, it is not difficult these days to get properly exposed pictures, but understanding some simple concepts and following some simple rules never hurt.

Most of us start out in photography by learning that our main subject should be facing the sun. After all, it says so right on the film box. That's OK for point-and-shooters, but YOU want more than that.

Consider placing your subject in the shadows. Yes, in the shadows! Though, not completely in the shadows. All right, not the dark kind of shadows where mosquitoes roam. But if you can find a good spot (for example, in the shade cast by the leaves of a tree) where light and shadows intermingle so that it is not a solid block of shade, you've got yourself an excellent spot for a pleasant picture.

Make sure you are also standing in the same shaded area (or shade your camera with our hand to avoid direct sunlight on your light meter sensor) so your camera's exposure meter is not fooled.

You might also choose to use fill-in flash to light your subject in the shade for a pleasantly exposed picture from corner to corner.

Backlighting
It also says on the film box not to shoot with the sun facing you. Again, rightly so because this would fool your camera's exposure meter into believing there is way too much light, resulting in an underexposed shot. However, taking a portrait with the sun behind your subject can result in quite a dramatic picture, if done properly. If the sun, or a another light source (such as natural light streaming from a window) is right behind your subject's head, you can get a pleasing halo effect. Of course, your camera's meter is now fooled and will under-expose your shot unless you adjust for it. If your camera has a scene mode for backlighting, use it. If your camera has buttons to allow you to adjust backlighting, use them. In addition, pop up your flash and take a fill-in flash shot of your subject. Voila, the face is properly exposed (thanks to the fill-in flash) and the halo effect is also achieved.

Sunsets
Sunsets are always beautiful and there are a couple of pointers here. Take a number of pictures at different exposure (this technique is called "exposure bracketing") as the sun sets. Since you are shooting into the sun, your camera's exposure meter is guaranteed to be fooled unless you use the appropriate scene mode or manually adjust your exposure one to two f/stops down. You gotta be quick 'cause once the sun gets to setting, it sets real fast! By taking a number of shots until the sun is below the horizon, your chances of getting just this one perfect shot increase. Now, I know, you can also go into Photoshop and adjust it after the fact, yeah, yeah, yeah.... :o) Interestingly, some digital cameras now has auto-bracketing where the camera takes a number of shots at different over- and under-exposed settings. One of those shots will probably returns the "correctly" exposed shot that your eyes automatically compensated for.

Fireworks
Forget it, those pictures of fireworks of the Eifel Tower or the Statue of Liberty are almost always composites! See, your expertise in Photoshop really pays off now, eh! To capture the full effect of fireworks, your camera needs to have a "bulb" setting that allows you to open the shutter and keep it open as long as you keep your finger there. You also need a piece of black cardboard or material that you put in front of your lens when bright objects pass by (e.g. a car) and then remove whenever fireworks explode. All the while, you keep the shutter open in the bulb setting. When you've got enough firework explosions, stop. Then, go into Photoshop and make a composite of all those fireworks explosions with your favorite landmark. Voila!

[ Read our Fireworks Photography Tutorial... ]

The Fair
Usually there are bright lights at the fair, and the surreal effect adds to the charm of a fair. Use fill-in flash for portraits. Use long shutter speeds (e.g. 1/30 sec.) to blur the spinning and twirling lights attached to the rides and carousels.

Scene Modes
Many digital cameras do not allow any exposure adjustment and so you are at the mercy of your camera. Others provide convenient scene modes for taking various situations, such as portrait, landscape, sports, night shots, etc. They essentially automate what we have talked about here. More higher-end models allow you to select your own shutter speed and aperture (f/stop) by providing shutter priority and aperture priority modes. We find that, if you are basically a point-and-shoot type of photographer, you will find the higher-end models confusing -- at first. Though we do not recommend any particular model of camera, we do recommend that you seriously consider those cameras that provide scene modes.

Here is a run down of the most common scene modes and what they mean technically. These are my own guesses and by no means the gospel on the subject matter. They also do not cover ALL that is going on when you select a certain scene mode on your digital camera, only the MAIN requirements, and only those I personally believe are the ideal requirements. Less than ideal specifications will no doubt still give great results in many cases.

Sports or Action -- 1) the camera chooses the fastest shutter speed it has (say, 1/1,000 sec.) and 2) then adjusts the aperture, starting from the largest aperture it has (say, F2.8) and going smaller until the proper exposure is obtained. 3) If, at the largest aperture, there is not enough light for a proper exposure, the camera selects to use the flash, and then cycles through step 2 again to obtain a correct exposure. 4) If there is still not enough light, the camera might attempt to switch to a higher ISO (e.g. ISO 400), and cycle through step 2 again. 5) Failing all that, the camera will select a slower shutter speed (not slower than 1/125 sec.) and retry steps 2 through 4. 6) Finally, if there is still not enough light for a proper exposure, the camera will progressively reduce the shutter speed until it has a shutter speed/aperture combination for correct exposure. These steps are just my guesses but seem to be what I would do manually. Different cameras may do steps 3 through 6 in different order. For example, a camera might select to progressively reduce the shutter speed (step 6) before opting to use the flash (step 3). 7) The camera might also select the correct White Balance if the shots are being taken indoors under artificial lighting (e.g. fluorescent or tungsten).

So the requirements for Sports or Action shots are:
1) Fast shutter speed (1/1,000 sec. and above)
2) Large aperture (F1.8 and larger)
3) ISO of 400 and above
4) White Balance for Fluorescent and Tungsten
5) Small shutter lag (you'll never catch the action if the shutter clicks 2 sec. after you press the shutter release)

Night -- 1) the camera selects the largest aperture it has (say, F2.8). 2) It then adjusts the shutter speed starting from the slowest (say 4 sec.) and moving up until correct exposure is obtained. 3) If there is not enough light, it might opt to use flash or increase the ISO sensitivity.

So, the requirements for Night shots are:
1) Large aperture (F1.8 and larger)
2) Slow shutter speeds (1 sec. and lower, plus Bulb)
3) ISO of 400 and above
4) White Balance for Tungsten

Landscape -- 1) the camera selects the smallest aperture it has (say, F8) for maximum depth of field. 2) It then adjusts the shutter speed until correct exposure is obtained.

So, the requirements for Landscape shots are:
1) A small aperture (F8 and smaller)

Portrait -- 1) the camera selects the largest aperture it has (say, F2.8) for minimum depth of field. 2) It then adjusts the shutter speed until correct exposure is obtained. 3) It might opt to use fill-in flash for correctly exposing the face. 4) It might zoom in to around 105mm to crop out extraneous surroundings.

So, the requirements for Portrait shots are:
1) A large aperture (F8 and smaller)
2) Fill-in flash
3) Zoom up to 105 mm

Museum -- 1) the camera shuts down flash. 2) It selects a shutter speed/aperture combination (and perhaps also the ISO sensitivity) for correct exposure. 3) It adjusts the White Balance for artificial light.

So, the requirements for Museum shots are:
1) Ability to shut off flash
2) Large aperture
3) White Balance for artificial light

In the next section, we want to deal with a subject that is currently a big disappointment with most beginners: blurred low-light indoors pictures.

<< Learn - Composition

Learn - Exposure: Low-Light >>

 

 

 

 



 

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