Bulb is a setting often ignored, but photographer Craig Roberts thinks it's something we should be paying more attention to. Here's why.
Posted: 14/12/2010 - 17:39
Night shots like this need long exposures of around 30 seconds, so use Bulb to open the shutter to record floodlit buildings.
Back in the old days, Pentax cameras, as well as all other makes, used to have a limited set of exposure modes. If you had a top end model, it would usually have manual, shutter and aperture-priority and bulb as your main choice. Today the latest SLRs, such as the K7, add program mode, together with unique shutter and aperture priority modes while the Optio compacts come with so many scene modes there are too many to mention.
Car light trails are an excellent subject for the Bulb setting. This exposure was 20 seconds.
Sadly, along with the basic manual mode, the bulb setting is often overlooked and so few ever get round to turning the dial to it. With all the other user-friendly exposure modes to choose from, do you really need to set B? Could the Bulb setting be left off the next model and be replace by another feature? Well, not really, because this mode holds the key to some creative photography and, if you like to experiment, this mode can be one of the most useful on your camera.
The latest cameras may have the advantage of ISO settings that go way beyond anything that was possible with film allowing you to keep the shutter speed high, even in low light, but by letting time pass by with the shutter held open, you open up a world of imaginative images.
The Bulb, or B-setting, allows you to open the shutter for as long as you like. The term bulb refers to the shutter mechanisms of cameras made in the late 19th century, where an air bulb release was squeezed to open the shutter and then released to close it again. Today it’s all done electronically, but the term has remained.
When shooting on the Bulb setting, there’s no metering to help you, so it’s down to guesswork. An alternative solution to give you a rough guide, is to whack the ISO to its maximum setting and use this increased sensitivity to get an exposure reading and then use some simple maths to work out the exposure with the ISO back on its minimum sensitivity. You can then set a small aperture of around f/16 or f/22 to allow for maximum depth-of-field and any focusing inaccuracies. But remember this leads to longer exposure times, which is what we are aiming for when shooting on the setting, so this is ideal.
Subject choice
Night subjects are a good choice for starters. Floodlit buildings are ideal and you will find that even a dull looking office block will come to life as a wonderful colourful shot with a few flood lights pointed in its direction.
Traffic trails are another popular subject. For this you need to position yourself up on a bridge or other high viewpoint overlooking a busy road and set your camera on a tripod. Open the shutter
and time an exposure of around 15 seconds or longer as the traffic passes. Check the exposure on the LCD screen afterwards and see if you need to shorten or prolong the next exposure if it’s not quite right.
If the traffic dies down mid-exposure, you can cover the lens with your hand or a piece of black card to hold the exposure until more cars arrive and then continue the exposure. A curved or snaking road and shooting into a sunset sky achieves best results.
Fireworks are shot in a similar way and the bulb setting allows more than one explosion to appear on each frame. It really is trial & error to get good shots of fireworks, as you never quite know where each one will explode, so make sure you take lots of pictures to get at least a few successful images and use a wide-angle lens to allow room for composition. Watching a few to see where they tend to go off will give you a better idea for framing.
You never quite know where fireworks will explode, so use a wide angle lens and the B-setting to capture as many on frame as possible. (20 seconds)
A night shot on Bulb allows movement to be recorded in the scene, as well as help remove people who are walking through the composition. (25 seconds).
Star trails and painting with light are both fantastic techniques to try as well. Star trails need exposures of anything between half an hour and four hours and are best taken in the countryside to avoid light pollution in your shots.
Light painting
Painting with light means pointing the camera at a subject with the camera set on B, while you draw round the subject or ‘paint’ the subject with light with a torch. You can even use a camera flashgun for this technique and just walk round the subject and fire the flash manually with the test button to light the subject.
Be careful not to stand in between the camera and flash as you fire or else you will appear as a ghostly figure in the picture. Again, trial & error will reward you with a successful picture. You can use this technique both out in the open or at home with simple still-life subjects on a dark background.
Fairgrounds offer a great location to capture light and movement with the B setting. Wait until it goes dark and shoot various rides to create images full of colour and movement. You can take daylight B shots with the help of neutral density (ND) filters. These are the solid grey type, not the
graduated ones used in landscape photography. You can generally buy ND filters with up to three stops exposure density, but to really give your photo a creative look, try a special 10-stop model from B&W filters. With one of these over the lens, you can capture a two-minute exposure in broad daylight.
Head on down to the coast and use the camera on B setting to capture the ebb and flow of the tide, as well as the movement in the clouds above. It’s best to shoot on a cloudy day and, with a solid object in the water to contrast with the movement, you’ll be amazed at how different your images will be.
Points to Remember
Make sure you set the camera to as low an ISO setting as your camera allows and therefore take the camera off any auto ISO setting, as the camera will automatically try to set a higher sensitivity in low light situations. High ISOs also increase the noise in a picture so image quality suffers.
To prevent further image quality loss, you could also activate the camera’s Noise Reduction feature. This works by the camera shooting a dark frame to identify the position of noise that can occur with long exposures. However, to enable the camera to do this, it will take it just as long as the actual exposure you just took. Therefore, a four-minute exposure is going to take the camera another four minutes before the final result is visible on the LCD screen and the next picture can be taken. At night you might not want to be standing around for this length of time in between images, so you may find that you can do without this and your images probably won’t suffer too much anyway.
Switch off autofocus as well and instead manually focus the lens as best you can in the darkness. The camera will be hunting around in the darkness anyway and a small aperture should compensate for any inaccuracies. While you can capture perfectly adequate images at 1/30sec or 1/500sec, to get really creative you need to slow things down. Beyond 30 seconds, the world looks very different than the way we see it with our eyes, so turn that dial to B and start recording time.
Use B-setting to open up the shutter for creative images. (25 seconds).
Guitar painted with torch light. This technique doesn’t only work in the outdoors. It can be useful in the studio as well. (25 seconds).
Hi-fi speaker painted with torch light (30 seconds).
As you hold the shutter open, any movement in the scene is capturedas a blur, yet can create very dynamic images (10 seconds).
Words and images by Craig Roberts.
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32 posts
15 years
UK & Greece
The only comment I would make - sometimes necessary to cover the viewfinder eyepiece during long exposures. some behind-the-camera lighting can impact on exposures.