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Photo Tips > Shutter Speed >

Bulb Shutter Speed

q

Shutter speed

About 4 minutes

Lens opening

f/4

ISO

400

The slowest shutter speed on most digital SLR cameras is thirty seconds (30").

If you need longer shutter speeds, you can use the bulb setting.

Do the following.

1) Set the exposure mode dial to M.

A few cameras have the bulb setting, B, on the exposure mode dial.

If your camera does, set it to B and skip step #2.

2) Turn the knob to scroll to lower-and-lower shutter speeds until you reach Bulb.

3) Do one of the following, depending on your camera.

a) Press the shutter release and hold it down.

The shutter opens and remains open until you let go of the shutter release.

b) Press the shutter release and let go.

The shutter opens and remains open until you press shutter release again.

This is called the Time setting on many film cameras.

Accessories: Needed & Not Needed

Tripod

Of course!

Remote Shutter Release

A remote shutter release is often used, but it usually isn't necessary.

A few cameras require the use of one in order to use the bulb shutter speed.

The camera movement that may be caused by pressing the shutter release is insignificant when the exposure is so long.

The same goes for locking the mirror up on some digital SLR cameras.

The vibration caused by the mirror flipping up is insignificant when the exposure is so long.

Neutral Density Filters

If the light is too bright for long shutter speeds, neutral density filters are used to block the light.

The strength of a neutral density filter is how many stops of light is blocked.

The filters may be labeled with a power value, such as ND2, or a density value, such as .3

Power Density Light Reduction # of Stops Blocked
ND2 .3 1/2 1
ND4 .6 1/4 2
ND8 .9 1/8 3
ND16 1.2 1/16 4
ND32 1.5 1/32 5
ND64 1.8 1/64 6
ND128 2.1 1/128 7
ND256 2.4 1/256 8
ND512 2.7 1/512 9
ND1024 3.0 1/1024 10

You can also purchase variable neutral density filters.

A Polarizing filter will block about one stop of light.

A cheap alternative is to use a welding filter.

AC Adapter

Long exposures may exhaust your camera's battery.

Bring spare batteries.

You may need an AC adapter for your camera.

You may be able to operate the adapter by using an inverter hooked up to a car.

Uses of Bulb Shutter Speed

Christmas (Holiday) Lights

Fireworks

Moon Photography

Night Photography

Painting with Light

Stars & Star Trails

Waves

Waving Black Card Technique

Also, go to Shutter Speeds: Long.

Language of Stop

Let's say you used an exposure time of one minute.

The photograph is a little too dark.

You add five seconds to the exposure time.

This second photograph looks identical to the first one.

Why?

To brighten the exposure by one stop, you would have to double the time to two minutes.

When the exposure time is sixty seconds, five seconds is insignificant.

Go to Language of Stop.

Etymology of Bulb

The term may be from the air bulbs used to trip shutters.

The bulb shutter speed feature was used with long exposures, which were more necessary due to the low sensitivity of plates, and later, film.

Photographers also had to open the shutter, ignite flash powder, and close the shutter.

More recently, film cameras had a B setting for flash bulbs.

The shutter was delayed slightly, allowing the flash bulb to come to maximum illumination.