Thinking Exposure

01st August 2016
In: Blog
Ok, so we have a scene in front of use. Several things need to be considered - composition, focal length, ISO, Aperture and shutter speed. All vital components for getting a decent result. But, more often than not, for me, it's shutter speed that is the most important - especially when trying to capture a hint of movement.

Take the following shot for example.




On an overcast day and with a bit of breeze blowing - when set up with my out of the box settings of ISO 100 and F/11 the image was showing an exposure time of approx 20 secs (the CPL filter adding a couple of stops). This was far too much. Upping the ISO to 200 helped and then adjusting the aperture to F/6.3 reduced the exposure to 3.2 seconds. This will blur the water sufficiently, retaining some structure, and also be short enough an exposure so the leaves on the trees keep their shape. Shooting at 23mm gives a hyperfocal distance of around 9 feet to give all the depth required. It does drive me nuts when I see publications telling you to shoot at F/32 and silly small apertures to get full depth of field. That's so wrong. As a rule stay well away from the small apertures as more often than not, although you'll get depth, you'll also get soft images at these apertures.

Here's another - the wind was blowing quite strong and what I didn't want was a blanket of blurred white cotton grass heads.



In this instance the aperture and ISO had to be increased to get sufficient depth when shooting at 40mm with a shutter speed at 1/40th sec. Which show how breezy it was....but it's resulted in capturing the movement and retaining some detail in the grass head.

So much to think about - but look at what's in front of you and determine what shutter speed is likely to get you the result you are after. From there, you can start adjusting the other settings. The advantage of digital is you can see your results instantly.

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