Tuesday 23 August 2011

Exercise - Measuring Exposure 2

The idea behind this exercise is to look at exposure and exposure measurement and see if alternative exposure give a better (more interesting) image. You were supposed to take images at the measured exposure and then bracket with 1/2 the 1 stop changes either side of this. I altered this slightly as my camera auto-bracketing at 1/3 or 2/3 jumps, and the alteration for increasing/decreasing shutter speed and exposures also work in 2/3 jumps. As this is the main camera I use it seemed sensible to get used to the variations this would give me.

Example 1.

This is the platform at a local steam railway restoration project. The image was taken outside, but under the cover - so the light was limited.  (1/3 stop bracketing)


Average exposure
This is a rather bland image although it does show details in the roof.

Light




This exposure shows more detail in the roof without markedly overexposing the whole image.







Lightest





This shows even more detail in the roof - but the rest of the image is washed out.







Dark





Here the roof shows less detail - but the colours in the wall posters are more vibrant.








Darkest






Here the image is definitely underexposed.












These do not show a very large variation in the mid-range exposure.  The preferred exposure depends on the object of the image and which area of the photograph you want to emphasise. I prefer the 'Light' image as I like the detail in the roof and this shows it well without completely loosing the details in the walls. The camera light meter has had a degree of difficulty in getting an exposure that evenly balances light and dark because of the major contrast between the roof and the wall.

Example 2.

This is a simple landscape shot of stormy clouds with a foreground of wildflowers (mostly rosebay willowherb).  (2/3rds of a stop bracketing)

Average exposure.


Light





In the lighter image the foreground appears brighter, giving an impression of a sunnier day, but the interesting detail in the clouds is decreased.











Lightest







Here the whole image is washed out, and all detail and interest is lost.










Dark






Here the detail and the looming nature of the storm is well shown and there is still a reasonable degree of brightness in the foreground.









Darkest






This shows the best image of the storm clouds but the flowers and cornfield are definitely underexposed.













Again the 'ideal' exposure depends on the image required, a lighter look seems sunnier, while a darker look shows the clouds well. I prefer the ominous look of the approaching storm in the 'dark' image. I would prefer the clouds even darker as in the final image but without the underexposure of the foreground. This could have been achieved in camera by using a neutral grad filter, or in photoshop by either superimposing the 2 images and erasing the unwanted areas of one, or by duplicating one image and altering one copy with levels and then removing the unwanted areas of one of the layers. The cameras meter has given an acceptable  but  unexciting image in the average one.

Example 3.

This is again the local railway restoration project, but this is taken outside on a sunny day. (2/3 stop bracketing)

Signal Box.

Light




Here the lighter exposure shoes more detail in the signal box but the sky is starting to look washed out.








Lightest





This is definitely overexposed, all the interesting detail and colour in the sky is lost, and even the signal box looks in need of a lick of paint!







Dark





Here the sky still looks good, but the signal box and track are underexposed and lacking in detail.







Darkest







Here it is definitely underexposed and even the sky is starting to look unnatural.









In this outdoor image on a sunny day the camera's light meter has done a good job of averaging out the areas and the medium image is the most pleasing and balanced.

Example 4.

Looking over heather in the borders, lots of clouds and some sun, the camera tended to 'read' the exposure for the sky which gave a very dark view of the heather. When focused on the heather the sky was a whiteout. In the end I used the multi-area metering and managed to get it to pick up some of the heather and some of the sky. This would definitely been easier if I had a neutral grad filter on the camera! (2/3 stop bracketing).

Average exposure.






With an increased exposure the sky is lacking detail, but the heather does not actually show much of a change.







Lightest






Here the heather is finally showing some interesting detail and colour - but the sky is completely blown out.






Dark





 Here the sky looks interesting but the brightness in the heather is lost again.








Darkest




This time I must have caught a glimmer of sun on the heather, but the sky look almost unnaturally dark.











I am not very happy with any of these exposures - and didn't feel any of them gave the feel of the sunlight and storm that was actually present that day, so I played around a bit in Lightroom and came up with this.

Heather on the Hills
I repeated this exercise on several more occasions and came up with similar results.


Lessons learned.
  1. The camera's light meter does not always give the best result
  2. Think about the purpose of the image and expose for that
  3. Sometimes more than one exposure can give an interesting effect, and the one you think will be 'best ' might not be.

No comments:

Post a Comment