Low exposure is a useful technique if you're taking photographs in low-light conditions or want to create an impressionistic effect. — dpa
When stars drift across the night sky or the water of a stream looks like a velvety veil, it can result in a fascinating photo. However, to get a picture like this, you need long exposure.
"Long exposure is a popular stylistic device if you want to blur people or even make them disappear completely," says Constanze Clauss from the Photo Industry Association in Germany.
It's a useful technique if you're taking photographs in low-light conditions or want to create an impressionistic effect.
"In principle, it's possible with any camera, you just have to be able to set the exposure time manually," says Moritz Wanke from Chip magazine. Many newer compact cameras and smartphones already offer the appropriate settings, but you can also use apps such as Slow Shutter Cam (iOS) and Manual Camera (Android) as well.
Often, however, the maximum exposure time allowed is 30 seconds.
"Thirty seconds is enough for a star photo, but not necessarily for the Milky Way," Wanke says.
It also depends on what you want to do with the photo. Pictures taken by simple cameras are fine for Facebook and Instagram, but if you want to make large prints, you'll need a more sophisticated device such as a system camera, which can be given a longer exposure time.
A tripod is recommended for long exposures because even the calmest hand can't hold a camera steady for more than a second, and camera shake will lead to blurry images. If you don't have a tripod on hand, a monopod, a beanbag or some other kind of firm base can suffice.
In the case of a smartphone, you can use a selfie stick attached to some solid object and then use a timer to take the photo.
One problem with taking long exposure pictures during the day is that the photo becomes too bright after a few seconds of exposure.
That's when you need a filter to put over the lens – something which is unavailable for smartphones and compact cameras.
"You also need a filter at sunrise or sunset if you're taking several minutes of exposure," says photographer Matthias Haltenhof.
Advanced cameras will give you more control over settings such as ISO value – this should be set to between 100 and 200, otherwise the picture will appear very grainy.
To focus correctly before taking the picture, it's best to look for a point of light such as a street lamp or the moon, Haltenhof advises.
If necessary, you can illuminate an object with a flashlight and then focus on it. Or you can set the focus on the lens to infinity.
To find out which shutter speed is right for the desired effect, you can play around with it and take a few test photos of different exposures. Haltenhof says he doesn't usually expose a photo for more than 10 minutes: "Otherwise the picture quality will be too bad."
The longer the exposure, the more "noise", or distortion, will appear in the image. However, that's something you just have to accept if you want to photograph the movement of the stars, for instance. — dpa
