EXERCISE: Your Camera’s Dynamic Range

First, find a scene with a distinctly high dynamic range.  The best conditions for this are:

  • Bright sunlight
  • At least one brightly reflecting surface
  • An area of deep shadow with a dark surface

Place the card or paper near the door in bright sunlight, as you will see, the lightness of any surface is a combination of its own characteristics and of the light falling on it.

Measure and make note of the brightness of the card/paper and of two of three of the darkest shadow areas.  With you camera, there are three was of doing this:

  1. 1.   Set the metering mode to ‘Spot’ if that is available on your camera
  2. 2.   If you are using a zoom set at wide for the photograph, zoom in to the maximum to measure just these small areas
  3. 3.   Walk close to the areas you want to measure s that they fill the frame.

Make a written not of these aperture/shutter speed combinations, and not exactly which areas you measured (it may help to make a paper sketch).

As per our instructions for this exercise, I dialled in the following camera settings:

  • As always, I shot this photo in manual, using my shutter speed to govern exposure
  • ISO 50 – the lowest my camera is capable of under these circumstances
  • To ensure clarity, I set my aperture at F9
  • I turned off all noise reducing functions within my camera
  • My metering was set to spot
  • And I set my auto-focus to single shot

For this exercise I struggled to find a doorway bathed in bright sunlight (as suggested by the coursework), but I was able to find a dark alleyway, on the 30th floor atrium of our apartment block.  To record all of my readings, I produced the following sketch, the original of which is in my sketchbook:

Sketch of Image and readings

Sketch of Image and readings

And below is a copy of the original image:

Original Image

Original Image

Once I found my position (kneeling down, so that I was on a level with the white card), I played with my shutter speed to find my just clipped reading.  At a shutter speed of 1/160 I received clipping on the card, but increasing this by one stop eradicated the clipping, so I was good to go.

As you can see from the sketch above, I obtained the following meter readings at an aperture of F9:

         White card:                                                                        1/200

         Brown Chair (in daylight):                                         1/40

         Green astro-turf in front of white card (in daylight): 1/125

         Beige wall (set in shadow):                                      1/4

Next, I loaded my image into Photoshop and ensured that any noise reduction was turned off.

It has taken me 24-hours to find out how to do this next part and after some emails with my tutor and SKYPE conversations with friends in the UK, I have been able to complete around 95% of this exercise.

Opening the “Select Target Highlight Colour” dialogue box (found under; Image> Adjustment> Levels> Sample in image to set white point), I moved the curser over the white card to find my RGB reading, which came out at R:242 G:239 and B:240.  Possibly a little lower than required, but as my photograph was taken on the cusp of the clipped highlights, it is the best reading I could achieve under the circumstances.

Select Target Highlight Colour Dialogue Box

Select Target Highlight Colour Dialogue Box

Moving over the shadows and brightening the image so that the details were visible, I took my second set of readings, which came out at R:31 G:36 and B:22; these were taken from the middle of the paved area, as show in the image below:

Shadow area used for 2nd readings

Shadow area used for 2nd readings

Unfortunately, at this time I am not able to translate this information into the dynamic range of my camera, but looking at some of the articles posted online, it appears that between eight and nine stops of exposure are the norm for the dynamic range of the Nikon D800.

This has been an interesting exercise to conduct, even though I have not been able to finish it completely; and the biggest challenge I have once again overcome is my use of Photoshop.  In my mind, this is great as not only am I learning about my camera and all of its functionality, but I am also having a crash course in the use of software.

I am a little dubious about this exercise and about the way the results have been obtained, and I found it very difficult to understand what was actually needed to obtain the results, but thanks to some understanding people I was able to achieve my goal – in a round about sort of way.  As with the other projects in this module, these results are very subjective and all boil down to your tolerance for highlights and noise, which is probably why the manufactures are coy about giving out their findings …  it is very interesting looking at these subjects and getting a better understanding of how light, dark and shadows all effect our images.

Source:

Bibliography:

blaff.  (2012) D800 Photographic Dynamic Range [Online Article].  Available at: <http://www.dpreview.com/forums/post/40577487&gt; [Accessed 4 June 2013].

Donegan T, J.  (2012) Nikon D800 Digital Camera Review – Dynamic Range [Online Article].  Available at: <http://www.digitalcamerainfo.com/content/Nikon-D800-Digital-Camera-Review/Dynamic-Range.htm&gt; [Accessed 4 June 2013].

Tobey, B.  (2012) Nikon D800 [Online Article].  Available at: <http://www.btobey.com/nikon/d800-review.php#performance&gt; [Accessed 4 June 2013].

Nicholson, A., Davies, A.  (2012) Nikon D800 Review – Noise and dynamic range [Online Article].  Available at: <http://www.techradar.com/reviews/cameras-and-camcorders/cameras/digital-slrs-hybrids/nikon-d800-1074183/review?artc_pg=5&gt; [Accessed 4 June 2013].

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