DPP - Part 2 DR Digital Image Qualities - Exercise 4 - Your camera's dynamic range

DPP - Digital Image Qualities - Exercise 4 - Your camera's dynamic range

The instructions for this exercise was to find a scene with a distinctly high dynamic range.

In addition to the front of the house light by winter sun I've also included an A3 sheet of white card and an open doorway.

The purpose of this exercise is to determine the dynamic range of the camera, in this case I'm using a D700.

I'm using the camera in Aperture priority and have left the camera matrix metering. In the image below I've spot metered on the brick wall just below the lantern. 

I've not needed to make an exposure compensation as the camera has correctly metered at the point just before highlight clipping occurs. This is borne out for the blinkies in the camera and confirmed when looking at the RAW file in CS6


Aperture of F/8 used a shutter speed of 1/500

This is the jpeg above. The image overall appears exposed OK.
I've not needed to make an exposure compensation as the camera has correctly metered at the point just before highlight clipping occurs. This is borne out for the blinkies in the camera and confirmed when looking at the RAW file in CS6



Aperture of F/8 used a shutter speed of 1/2500

This is the jpeg above. Metering for the card the camera has reduced the overall exposure so that the card is not blown out. To achieve this the camera has used a shutter speed of 1/2500, 5 times quicker than the image above.  The result is that the image in general appears under exposed elsewhere.


Aperture of F/8 used a shutter speed of 1/250

This is the jpeg above. Metering for the dark elements in the door way the camera has selected a slower shutter speed which has resulted in all other areas of the image being over exposed

Using the following website I was able to quickly calculate the dynamic range between the 2 exposures, based on the shutter speed difference, was 3 1/3 stops. The camera when not using spot meeting selected a shutter speed of 1/500 as the average exposure which is a difference of just one stop from 1/250.


Zooming in on the first image using the RAW file and getting to 100% zoom crop on the white card using the eye dropper I can see how good the camera has been in its exposure, as mentioned above. The image below is recording, outlined red:
Red       = 251
Green   = 251
Blue      = 252

Continuing the exercise bringing out the detail from the shadows using the exposure tool its maxed out giving a dynamic range of 6.5 stops

Going on to the website DXO Mark, which is a well known company running tests against a vast number of cameras and lenses I found for landscapes the camera is tested, at least for landscapes, per the test to have a dynamic range of 12.2 EVs

http://www.dxomark.com/Cameras/Nikon/D700

As this is an independent company rather than the manufacturer I'm assuming these tests to be accurate but who knows, perhaps something went wrong for me with this exercise

There is some interesting information here on this website which details some interesting facts about the dynamic range and low light sensitivity of the human eye and comparisons between the eye and a camera's abilities:
http://www.cambridgeincolour.com/tutorials/cameras-vs-human-eye.htm

The aperture in the human eye is the pupil and the eye can quickly scan the view in front of it focusing and adjusting across the scene and the brain will also fill in any missing gaps. Alas the camera has just the RAW image to show for it. As I mentioned in an earlier exercise a big disappointment for amateur photographers can be the realisation that the camera cannot always copy what the eye sees then again like the eye, it needs some help in being told what element of the image it should focus on and adjust to.