Sunday, May 22, 2011

Sunday Selections - Longer exposure

Another  blog for Frogpondsrock 's Sunday Selections! Go and check out hers and all the others linked there!


In last weeks Sunday Selections I talked about aperture and depth of field. I briefly mentioned the use of varying exposure time to gain different results, and thought I would post a few photos I have taken over the years that use slightly longer exposure times.


To vary exposure time, your camera needs the ability to function in shutter priority (Tv or T) or full Manual (M) modes. ISO is also a key part of exposure. ISO relates to how much light is needed to correctly expose the shot. Film comes rated at a specific ISO (usually 100), but digital cameras may allow you to adjust ISO manually.


A good analogy is to think of exposure as a bucket (film or sensor) to be filled with water (light). ISO determines the size of the bucket. The smallest ISO, usually 80 or 100, is equivalent to the largest bucket. A small ISO is a good thing, as lots of light = lots of detail.  Having a larger ISO allows you to capture photos in darker environments. A digital Camera may try and increase the ISO to allow a faster shutter speed, reducing the possibility of blurring of any movement.


Exposure time is measured in fractions of a second, or seconds in the examples I will show here. A typical photo might be 1/250, 1/500 or higher. At these speeds any motion is frozen, hopefully giving you a good sharp photo. Once you get below these speeds, it is more likely blur  will creep its way into your shot, either through movement in your subject, or movement in the camera.  For longer exposures, it is vital the camera be kept still, using a tripod, or some other handy object to sit the camera on.


Ok, enough talking, time for some photos. Oh, and please click on the photos to see them at a decent size!


This photo uses a longer exposure to achieve a good exposure in a low light situation, capturing the light from the environment. Exposure details for this photo of the Royal Tasmanian Yacht Club are: ISO 80, shutter 8 seconds, aperture f/5.6. A post used to rope off the yachts was used to sit the camera on for the shot.




This photo taken in Myrtle Gully, Cascades,  uses a longer exposure to change the look of the water flowing in the creek. It gives the water a 'molten' look, which usually looks quite nice. ISO 80, f/7.1, 6 seconds. Camera on a tripod in the middle of the creek, me with frozen feet!



In a similar type of shot, longer exposures of waterfalls change the look of the water to produce a nice flowing effect. DEtails of this shot of Horseshoe Falls, Mt Field: ISO 100, f/11, 10 seconds



Moving away from water, longer exposures can also be used to show the movement of light over time. This shot of a rather nauseating ride: ISO 80, f/5, 3.2 seconds



And this photo of fireworks: ISO 80, f/7.1, 5 seconds


Similar to the first photo in the collection, the use of a longer exposure time allowed the capture of the early morning light, with the moon, stars and the imminent sunrise all visible. ISO 160, f/4, 10 seconds


And the shot taken a short time later showing the great colours of sunrise: ISO 100, f/5.6, 13 seconds.


6 comments:

  1. Wow! Pretty photos Marc. I love that 'molten' look of the water - that was well worth getting wet feet for :) I love the colours in the boat shot too.

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  2. Arghh - my first comment got eaten.
    Lovely shots - and thanks for the interesting photography info. I have such trouble working it all out and have to fiddle with settings and take a zillion shots to get the one I want. Quite happy with my moon shots from this week though :)

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  3. Gorgeous photos, I wish I had the expertise to take these, mine are more just point and shoot and sometimes I get lucky. I will have to take a photo course once I retire.

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  4. The water in that second shot looks like silk. Wow. And indeed wow to all of them.

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  5. Thanks. I have moved to http://marcbester.com

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