Sunday, February 24, 2013

Shooting in Low Light

Crypt - Notre Dame de la Gurde
24mm ISO 200 f3.3 1/30th no flash
Getting good photos in low light can be one of the biggest challenges photographers face. Low light photos require longer shutter speeds larger apertures and higher ISO to get proper exposure, and all of these add their own challenges to the photo. In an ideal world you would have a camera with a large sensor and fast lens to help correct these issues, but lets face it, even those of us that are professionals and “have all the gear” don’t really have all the gear for every situation. We also commonly find ourselves in a situations where we only have basic gear with us because we did not know this opportunity would arise to get this photo.

Lets first look at the challenge of a longer shutter. Shutter speeds over 1/60th start to show camera shake, possibly faster shutters will if you are zoomed in on your subject. Motion blur will also be an issue, and can be even if you can get speeds as high as 1/250th, depending on what your subject is. A couple of options you have to combat camera shake are the use of a support and the use of your time released shutter. If a tripod is available it is the best option as they provide very good support which will eliminate movement of the camera, but you wont always have one, and some places do not allow their use. Learning to brace your camera against your body, elbows in and pulled against the ribcage or squatting with your elbows resting on your knees will help steady the shot. Often the depressing of the shutter release can be enough to introduce shake even when in positions that offer better support. Many cameras have a timed release that can be set to 2 or 10 seconds, use of this delay will eliminate those issues.

Of the three setting on your camera the one that is the easiest to use in low light is a large aperture. Its only real challenge is providing a deep enough field of focus for your subject, the depth of field is increased by moving back from your subject and then zooming in with the camera lens or by cropping the image later on a computer. Todays cameras with megapixel ranges above 12 offer plenty of room to crop. But you can still face other challenges here. Many lenses have a variable aperture, that is the aperture will be something like f3.5 at 18mm but as you zoom in to your subject the aperture drops to f5.6. This means digital cropping later may be your only option for having a deep enough field of focus.

ISO speeds can be the most challenging aspect of low light photography. To the novice ISO will often look like the easy fix and it will be their, or their cameras, response to low light. After all higher ISO lets you shoot in lower light, however this can quickly introduce noise, while a little bit of noise is not that detrimental to an image a lot of noise can destroy it. True there is noise reducing software but it can be expensive and difficult to use effectively. Fortunately newer cameras are better at recognizing and correcting for noise, and if you are shooting with a DSLR it has a larger sensor which is less susceptible to noise. But really the solution for this is experimentation. Shoot a lot of things in low light on different ISO settings and find out what your noise threshold is and what ISO settings are below it. Use these ISO settings and correct the exposure from there with aperture and then shutter speed.

In “The BIG 3” I mentioned that there is really a 4th option - the addition of more light. Generally this will be a novices solution too, turn the flash on. On camera flash is one of the quickest ways to ruin a good photo (I will go into that more when I write about lighting) but also in many places it is not allowed or at the least can be rude - in a cathedral for example. The photo above was shot in the crypt below Notre Dame de la Garde with a Panasonic DMC-ZS10 with available light. The aperture was f3.3 and the shutter was 1/30th of a second, while the ISO was set for 200. This is not a camera with a large sensor or a particularly fast lens, but by bracing the camera on a rail and using the 2 second delay on the time release settings for the shutter I was able to get a very nice image, just with available light coming in from the entrance. This was shot in jPeg and the only post work was the addition of a vignette to help push attention to the sarcophagus.

Conversely when working in a studio it is possible to fake low light. This has the added benefit of allowing the use of camera setting that are normally only available in daylight like conditions (again I will go into this in much more depth later) but the short version is by adding light, usually off camera, you can eliminate the issues of high ISO, large aperture, and fast shutter, but by using light settings that are “under exposed” according to the light meter and then playing with the color temperature settings of your camera you can create the illusion of shooting under candle light or moonlight while using a shutter of 1/100th an aperture of f9 and an ISO of 200.

Follow Us




No comments:

Post a Comment