Photographing In Low Light
Which lens to use ?
The do-everything zoom lenses furnished with dSLRs often have maximum apertures of f/3.5 to f/4.5. The entry-level Canon, Nikon, Sony, and Pentax models are all furnished in kit form with 18mm-to-55mm f/3.5-to-f/5.6 zooms.
You can’t compare the focal-length ranges directly, of course, because these popularly priced dSLRs have different crop factors (which I describe in Chapter 2), ranging from 1.5X (for Nikon, Sony, and Pentax) to 2X (for the Olympus line). But you can compare maximum apertures, and f/3.5 or slower is common among every manufacturer’s starter lenses.
Although zooms that have large maximum apertures are expensive (and for a zoom lens, f/2.8 is a large maximum aperture), you can find fast fixed focal length (prime) lenses that cost very little. For example, a 50mm f/1.8 lens from a major camera manufacturer may cost less than $100, even though it’s two f-stops faster than an f/3.5 lens and three stops better than an f/4.5 optic.
If you’re willing to spend a little more, you can buy 28mm, 35mm, 50mm, or 85mm f/1.4 lenses from the larger lens companies and speedy third-party lenses, such as the Sigma 30mm f/1.4 and Sigma 20mm f/1.8. Those extra notches on the aperture ring let you take hand-held pictures in dark environ- ments (especially when the camera or lens uses image stabilization, which I discuss in Chapter 7), as shown in Figure 6-1, without resorting to detail- robbing high ISO ratings. An indoor concert that calls for a 1/15-second exposure at f/4 and ISO 100 may work just fine at 1/125 of a second at f/1.4.
The fastest lenses are generally designed to produce good results wide open, too, so you needn’t fear using f/1.4 with a prime lens, even though you get poor results with your zoom at f/4.5.
Go for faster shutter speeds - That wide aperture also pays dividends in the shutter-speed department. The difference between f/1.4 at 1/125 of a second and 1/15 of a second at f/4 can be quite dramatic from perspective of sharpness. You can find out more about making the most of slow shutter speeds by using image stabilization technology.
Go for Sharper lenses - You may be able to get sharper images by switching lenses, too. That’s not to say that the lens you purchased with your camera is unsharp. However, your do-all lens is built on a foundation of compromises that don’t necessarily produce the best results at all zoom positions and all apertures. Other lenses that you add to your collection may provide better results at specific focal lengths or f-stops. For example, that 50mm f/1.8 lens that you pick up for less than a single Benjamin just might be the sharpest lens you own. Or you might buy a close-up lens that’s optimized for macro photography and produces especially sharp images at distances of a few inches or so.
Your current lens is probably very good, but that doesn’t mean you can’t get sharper pictures with another set of optics, particularly when you’re swap- ping a general-purpose zoom lens for a fixed focal length prime lens designed for exactly the kind of photo project that you’re working on at the moment.
‘Photography is all about light’, we have heard this a thousand times. It’s true – light makes all photographs. When there’s an abundance of good quality light, there’s no denying that it becomes easier to take a good picture. We need to bother about the quality and direction of light and the quantity is not an issue at all. This doesn’t mean that one ha to stop shooting when the light starts to disappear or avoid low-light photography altogether, though; things just get a bit trickier and one has to know how to set up the camera to make the most of the failing light.
Low light photography means capturing a good picture with minimal lights around. Keeping the shutter open long enough and wide enough to let in sufficient light is what low light photography means. Today's cameras include several features to improve a dimly-lit photo, including adjustments for flash, color, focus and depth of field.
The biggest solution to low light photography is flash light or the external speed light. The problem with this is that not all situations can benefit from using the flash. Not only does it interfere with your “moment” socially and artistically, but the flash can flatten out your digital images. This is especially true for a flash that is built-in on digital cameras. The built in flash (and a flash in general) has the effect of lighting your subject on the front only which compresses the depth in your digital photos. Compressed depth can really decrease the beauty of your subject in your digital photography.
Really, a good way to combat the problem in low light you can try using a higher ISO. In digital photography, a higher ISO allows you to take photos in low light situations. Your ISO simply means the amount of sensitivity of light falling on your sensor. For example take traditional photography as a comparison to digital photography. Traditional photography ISO will be film sensitivity. (ISO in traditional terms works with film speed as well.) The only set back in digital photography ISO is noise. If your ISO is perfect for the photo yet there is a significant increase in noise you can use software to sharpen up your digital photo. If you don’t push the ISO higher you may find the problem with camera shake if a tripod is not in hand.
Another example for the use of ISO could be- Let’s take for example you are taking dome shots indoors, like someone speaking, or playing an instrument. Perhaps the flash is not appropriate in this situation. In this case (which happens a lot in digital photography) you would simply adjust the ISO to a higher setting. If you set the camera on “ISO Auto” your digital camera will then detect that a higher ISO is necessary. Alternatively you can set the ISO yourself. This higher sensitivity can give you the opportunity of gaining the right exposure for the shot.
TIPS FOR LOW LIGHT PHOTOGRAPHY
Although it is ultimately the quality of light rather than the quantity that makes a successful picture, low light does provide challenges that you don’t face in bright conditions. In particular, the resulting slow shutter speeds mean that camera shake can become a significant problem. The simple solution is to use a tripod. Despite the inconvenience, a stable three-legged support allows you to use any aperture you like, without worrying about how slow the resulting shutter speed will be. Digital cameras are much better at adapting to low light than film cameras, thanks to their white balance control, and a tripod allows you to take full advantage of this fact. When a tripod is not available, or if the subject is moving, digital cameras allow you to increase the ISO setting (sensitivity) of the sensor. Although this can mean slightly grainier pictures, it is preferable to missing the shot or ending up with a blurred image.