DPP - Part 2 DR Exercise 5 - Scene Dynamic Range
The purpose of this exercise was to take 5 differently lit scenes and measure the dynamic range across them.
My plan has been to use an aperture of f/8 and take an image that has been matrix metered. I've then used spot metering across the scene I've initially captured to determine the dynamic range across the image using the calculator at this site
Image 1
Overall the scene was metered with an aperture of f/8 at 1/400s
The dynamic range between the two points indicated is 4 stops, the camera using matrix metering metered almost exactly between the 2
Image 2
Overall the scene was metered with an aperture of f/8 at 1/500s
The dynamic range between the two points with the largest difference indicated is 4 and 2/3 stops, the camera using matrix metering has metered to expose the largestt element present in the image, the grass
Image 3
You can see from the image that half is in the shadow of the building and half isn't.
Overall the scene was metered with an aperture of f/8 at 1/800s. However its interesting that there are almost 4 different bands of lighting across the image
Image 4
Overall the scene was metered with an aperture of f/8 at 1/160s, a dimly lit scene.
The camera has metered to expose the flower exactly. There are 1 and 1/3 stop between the darkest and lightest elements in the image
Image 5
Overall the scene was metered with an aperture of f/8 at 1/2500s, The dynamic range between the two points indicated is 6 and 2/3 stops. The matrix metering in this instance has metered closer to the sky than the grass, the overall metering being just 1 and 2/3 stops less than that required for the sky alone
Lessons learnt
a) The camera using algorithms will try, when in matrix metering mode, try to create an image of average exposure when there are variations in the dynamic range of image
b) Using spot metering it is possible to determine the correct exposure for each element within the scene that you want to capture
c) The histogram will show how well the image has been exposed and also let the photographer now where clipping may have occurred
d) Using the camera screen the photographer view the image and determine if the camera has exposed the image in the way they wanted, or perhaps even to determine from this point what changes are required to creatively construct an image. This could then be done by either adjusting the exposure through the exposure controls or moving to complete manual mode and adjust directly by changing aperture or shutter speed. Personally I would use the exposure compensation button to do this
e) Understanding the camera will for the most part expose satisfactorily, use of histogram / view image in camera will give major help in making changes where the photographer may want to change the exposure from how the camera calculates it
f) In general when post processing more detail can be recovered from an under exposed image than an over exposed image so it pays to err on the side of caution and under expose slightly when in doubt
f) The camera's ability to convert a scene may vary between camera's and most certainly vary between how the human eye exposes an image. This is probably the biggest frustration to new photographers in not being able to capture an image as seen by their eyes, indeed holiday snaps of people, where issues occur, are normally where the person is back lit by the sun behind, the camera exposures for the bright light and the person's face is put into shadow
g) When using a tripod bracketing may allow the full dynamic range to be captured across multiple images where this range is to great for the camera's sensor
