Sunday, 6 June 2010

Exercise 8: Camera Dynamic Range

Here is the photo used as the basis for this exercise. I followed the suggested subject in the notes as my front door is a close match to the suggested arrangement.
In the full size original the piece of white card (behind the doormat) shows some clipping in the bottom right corner but checking with the eye-dropper tool shows RGB values less than 250 for all but the extreme bottom right. The exposure was 1/200; f/11;ISO 100 - about 2/3 of a stop below the camera recommended figure.
The blue carpet on the stairs has a small pattern which is useful for this exercise.
The metered figures from around the scene are given in this picture (all at f/11, with 0.7 EV underexposure dialled in as per the original shot). This is clearer in the full size image.
The reading on on the white card is 1/1000 sec. Just above the envelope on the stairs is a black shoulder bag (on the second stair) which records a reading of 1/3 sec. The stair pattern is clearly visible without too much noise interference. By the seventh stair (1.3 sec – approx 2 stops darker) the pattern is lost in the noise, so the bottom end of usability is around 2/3 sec giving a practical dynamic range that runs from about 1/1000 to 0.6 seconds – around 9 stops – which compares reasonably well with the lab figures on DP Review a well known (and respected) source of digital camera reviews

No comments:

Post a Comment