Canon XSi Extended Exposures

Extended exposures are useful for showing water flowing, cars driving (brake light trails),  or taking a photo at night  when there is minimal light.  Most extended exposure photos require the use of a tripod – otherwise the images will be shaky and look bad.  

Two methods for achieving extended exposures easily are:
1) place camera in Tv shutter priority mode; set your shutter at longer speeds ranging from 1/8th of a second to 30 seconds or longer via the use of a shutter release cable. 

2)  place camera in manual mode, set your shutter speed at longer speeds and your aperture to a small number so less light is let in.  If the photo is taken at night, larger apertures will allow for more light to be let in and shorter exposures required.   At night, the longer the exposure, the more noise you will have in your photo.

 

 

 

As you can see with these photos, by extending your exposure time with a longer shutter, you can achieve movement and light trails, and properly expose sunsets and evening skies. Due to the extended shutter length, these shots all used a tripod, and a standard lens.  The camera was set to ISO 100 – the lowest sensitivity,  the lens aperture was narrowed to F/8-F/11, and the exposure was varied between 3 and 5 seconds.

What if we were taking these photos during the middle of the day and wanted to achieve the same effect? We could narrow aperture, and increase shutter speeds, but it is likely our shutter speed would never be long enough to capture movement during the day. When we narrow aperture too much, we introduce diffraction and a softening of the image. We can can reduce the shutter speed but you would lose that silky movement look, so instead you can wait for dusk or night, less light will permit longer exposures without over exposure. The darker the ambient light, the less risk of over exposure. 

The second way to take extended exposures is by using neutral density and circular polarizer filters to add additional aperture stops to your lens.  By adding one or two neutral density filters with 3 stops, you can add an additional 6 stops of light to your sensor, thereby allowing you to take the photo with a longer shutter speed  while also keeping too much light from over exposing areas of your photo. 

Here is an example of waiting until night time to take the same photo.   As you can see, i was able to capture the falls movement, and didn’t suffer from the ambient sun light over blowing the photo.  An inexpensive “remedy” when neutral density filters are not readily available for your use.

17mm, ISO 100, F8, 20 seconds

Here is an example of an extended exposure combined with hyperfocal distance focusing.

City exposures at night:
Here is a photo taken with the original digital rebel

This photo was taken right at sunset, the sun had already gone down and the sky appeared mostly black.  Through a 20 second exposure i was able to capture headlights driving, added ambient sky color, and more colorful lights from the buildings.  Again not a perfect photo, but a nice example of an extended exposure.