shutter speed vs light...help?????

[Lens Uncapped]

hi there, I am quite new at the technical side of photography, but I learning very quickly.

one question that I can't seem to figure out on my own is regarding shutter speed and lighting.
when I try to slow the shutter speed down for a cool waterfall shot or fireworks or something like that, the lighting is so bright that it ruins the picture, and when I increase the shutter speed, the picture might as well be black.

help?

[Skoropada]

Three main variables come into play for getting a correct exposure: shutter speed, aperture and ISO.

There are several values for each of the variables that, combined correctly will get you the same exposure.

I suggest that you search this forum for the exposure triangle. You'll get a lot of information about it.

[RichardTaylor]

This tutorial may help.

Exposure (1) A balancing act


Basically for waterfalls, you slow the shutter speed down and make your aperture smaller, and shoot at minimum ISO. If your pics are still over exposed you will need a neutral density filter to reduce the light coming into the lens.

[GreggObst]

You might also benefit from playing around with the online digital SLR camera simulator where you can make adjustments to Aperture, Shutter Speed and ISO and see how each affects your image and try to come up with a combination that works for the different types of shots you wish to take.

CameraSim simulates a digital SLR camera - SLR Photography Demystified

Specifically for waterfalls, you need to be able to knock down the available light in the scene by quite a few stops before you will be able to get that milky white effect. To do that, use a neutral density filter that screws onto the front of your lens. Set the camera on a tripod. Set the ISO to the lowest number that is native to your camera, so usually around 200 or 100. Set the camera to shutter priority mode and set the shutter speed to around 5 seconds. You can try playing with the shutter speed up and down to see how that affects the appearance of the water in the shot. Vary nothing other than the shutter speed. I would recommend either a wired or wireless shutter release or using the timer function on the camera to trigger the shutter after a 5 second delay so that you don't pickup any camera shake that can occur at low shutter speeds when triggering the shutter button with your hand.

Hope that helps.

[inkista]

Longer shutter speed -> more light (more blur)
Higher iso setting -> more light (more noise)
Larger aperture (lower f-number) -> more light (less depth of field)

Which tradeoff do you want?

[For way more information on all this, I'd suggest Bryan Peterson's Understanding Exposure].

If you want your shutter speed to be slow enough to register blur, you should stop down and use a low iso, and even if you bottom out both of those, depending on the light in the scene, you may still not achieve what you want. Which is why we have neutral density filters.

ND filters are like sunglasses for your camera. They're dark grey (color neutral), and they block light from the getting to your lens, so you can use slower shutter speeds in brightly lit conditions. How dark a filter you need again, depends on how slow you want to go and how much light is in the scene.

An ND filter is usually rated in stops. A stop is a halving/doubling of the light. So, if you can get the camera down to 1/30s with a good exposure, but no more, but you want to have 2 second exopsure, then you'd need:

1/30 -> 1/15 -> 1/8 -> 1/4 -> 1/2 -> 1 -> 2

Six stops. Or 2⁶ => ND64 filter.

I live in Southern California where we have lots of bright sunlight all the time. I like really long exposures of about 30 seconds. I use a 10-stop filter to turn ocean waves into mist.


Canon 50D, EF 24-105 f/4L IS USM @24mm, B&W 110 (10-stop ND filter).
iso 200, f/22, 30s. Tripod. Mirror lock-up. 2-second timer.
Shot RAW, processed in Lightroom, white balanced with Whibal shot with same exposure settings.