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11-20-2008, 02:31 PM   #1
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Trying To Lay the D-Range Question to Rest

I've been reading about what people dispute what D-Range is and have seen several examples. I always thought it was your good old run of the mill s-curve applied before jpeg processing though I've read several contradictions. I've never seen an actual technical test and decided that today, with a little free/sick time, I would make a crude attempt at it. I started with printing out several blocks ranging from black to white with the ones between evenly spaced out within the range. I also had a smooth gradient printed on the page because I wasn't sure which would show better evidnce - In the end the blocks make it easier to see the effect. I then took a picture with a K200d set at Natural and zero on all settings with the 2 second timer. The camera was on a tripod set to manual (1/60 f5.6) with a FA50mm 1.4. I only used artifical light in a dim room - an AF360. Both shots were taken the same way within 20 seconds of each other. I used the ISO200 D-Range and the standard ISO200 settings shot into jpeg high quality. The only PP I did was set the levels in both images - white on the white block and black on the black block. It appears I was wrong with my assumption. Here are the results:

The D-Range image is on the top and the standard image on the bottom. It looks like all the camera is doing is snapping the image at ISO100 and pulling the image to ISO200. The differences are linear and not curved. One problem I ran into was the smooth gradient that was on the paper that I didn't post. There was a gross offset of colors towards the white end. The D-Range shot turned into a light cyan while the standard stayed true to shades of grey. In the end, it looks like D-Range was intended to help users print directly from the card. If you intend to do any PP it would seem that leaving it off would be better and of course RAW would give you the most headroom.

-Brian

12-14-2008, 09:35 PM   #2
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I'd like to see more test shots. Lookin good
12-15-2008, 04:16 AM   #3
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Thanks Brian. Very interesting results. This will make me think more about D-Range.

You said the images you've shown are from the JPEGs - but did you shoot in RAW? If so, how did they come out? Perhaps you could post the mostly unprocessed RAW images (ie default conversion settings) as PNG or PSD to look at.

Obviously having sickies does have its advantages.....
12-15-2008, 05:00 AM   #4
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Thanks. I ended up jumping into this a little more here: D-Range A Technical View
It ended up getting a little off-topic, but is a lot more technical than what I had done here.

-Brian

12-17-2008, 02:58 AM   #5
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QuoteOriginally posted by the_int21h Quote
I've been reading about what people dispute what D-Range is and have seen several examples.
-Brian
It does just use a lower ISO, then expands the levels.

So it essentially underexposes and image then brightens it.

This is why the shadows get murky. I noticed this right away the first time I used the feature.

I don't know if there is an advantage to doing it in RAW yourself. My guess is there is some noise reduction applied, and probably the results with the K20D (as opposed to the K200D) have some on the sensor noise reduction.

So your next test should be to compare the automatic DR expansion vs. Lightroom DR expansion.

Anyway, I actually liked the feature. Most mid day shots aren't going to make the front cover of National Geographic anyway, so I'm not so worried about the murky shadows but appreciate the lack of blown out highlights.

My dog is white, and when taking shots with him in it, in bright overhead sun, this kept his coat slightly less clipped.

I've been saying all along, no reason to leave this setting on. Use it for mid day on the fly shooting but use filtration (double exposures merged, or a glass GND) to equalize your D-range in shots where you can use a tripod. Turn it off for everything else.
12-25-2008, 01:39 PM   #6
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QuoteOriginally posted by Mountain Vision Quote
It does just use a lower ISO, then expands the levels.

So it essentially underexposes and image then brightens it.

This is why the shadows get murky. I noticed this right away the first time I used the feature.

Anyway, I actually liked the feature. Most mid day shots aren't going to make the front cover of National Geographic anyway, so I'm not so worried about the murky shadows but appreciate the lack of blown out highlights.

My dog is white, and when taking shots with him in it, in bright overhead sun, this kept his coat slightly less clipped.

I've been saying all along, no reason to leave this setting on. Use it for mid day on the fly shooting but use filtration (double exposures merged, or a glass GND) to equalize your D-range in shots where you can use a tripod. Turn it off for everything else.
Much appreciated, you posting this, Mountain Vision, (and theint) There's a whole lot with my new K20d to try, and that's one more thing covered: this feature could come in pretty handy for me, on occasion, actually.

Last edited by Ratmagiclady; 12-25-2008 at 02:11 PM.
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