I've had a little free time latley and decided to jump into measurbating (oh no!). I tried a personal test yesterday to see exactly what D-Range did and if I wanted to keep it on or leave it off. I figured out this morning that what I did yesterday was flawed. I started scowering the net and came across a program called Imatest which offered 20 free tests in its trial. It seems like a wonderful program although the only part I used was the dynamic range/noise portion. I set up my studio and within an hour or so I came up with some results. Before I share, I want to let you know the setup:
Camera: K200d - Natural - all set to zero - w/flash WB also set to zero
Lens: FA 50mm 1.4 - Manual Focus
Lighting: 2 strobes @ 45 degree angles shot through umbrellas w/ manual equal power
Exposure: Manual 1/15 @ 5.0 (2 sec delay - mirror lockup - cable switch)
Chart: Kodak Q-13
First here are the results:
It's interesting to note that in the stepchart analysis chart the lower end stays the same while there is about a 2-3% gain toward the upper end in the DR-On chart. The density response chart also backs this up. Note that the actual noise values (the diamonds) in both noise charts are about the same, i.e. crappy in the extreme dark areas. Not as bad as some people made it out to be, even in the camera manual. Also in the stepchart analysis you can see the pronounced difference of a more rounded shoulder in the lighter areas of the DR-On chart. Before I go on, I would like to say that the D-Range image straight out of the camera appeared slightly darker in the white areas while taking multiple shots and keeping constant lighting conditions. This was illustrated in both charts.
Now on to real world conditions. For sh*ts and grins I wanted to see what would happeded if I took the test images and adjusted the levels - just for black and white points... that's all - nothing else. I then retested and here's what happened:
It seems that after the images were adjusted, the highlights were retained in the DR-On image while they disappeared in the standard shot. This ends up being about a 9-10% gain in the upper dynamic range! Still, the noise levels remained to be the same in both shots - even in the lower levels. Also the histograms showed some moderate banding in both shots.
I'm not sure exactly what the camera is doing internally, but have decided that it is in my best interest to leave the D-Range on while I shoot in Jpeg (of course RAW is best, but I don't need it all the time). The fear of lower light noise is unwarranted and the extra gain in the upper end is nice to have. This is my kindling to throw into the fire and I'm sure there are a few people waiting with cans of gas. I hope this helps some of you and inspires some knit-pickers.
-Brian