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01-24-2008, 02:18 PM   #1
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K20D dynamic range enlargement?

This question is from a decidedly non-professional 6-month K10D user: What's the "Dynamic Range Enlargement by 1EV" in the K20D really mean, technically?

Is this just a somewhat-misleading marketing buzzword for post-processing you could do yourself as well in Camera Raw/Photoshop Saturation, Contrast, Exposure, and/or Shadows? Or is it honestly a fundamentally improved way to extract both better highlights and better shadows without sacrificing any mid-range nuances, as the picture is snapped? In other words, does it affect the RAW file in any way, or just the JPG version?

Also, I'm confused by the fact that this feature can be turned on or off.(?) Seems like a very significant benefit you'd always want. What might be the drawbacks? Would your images look unnatural on media not specifically set up for HDR? Would the RAW files be significantly larger, as implied by a larger digital range? Can the resulting RAW files still be read by the current version of Adobe Camera Raw? Perhaps this explains the apparent uncertainty here as to whether the new ADC converter is 12 bit or 14 bit?

01-24-2008, 02:24 PM   #2
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I have been asking myself this question too. The only good answer I have been giving myself (and I was not sure when I told myself this) is that maybe they will read the sensor twice. First after half the exposure time, and then again after the full exposure, then they somehow merge those pictures together? But again, this is just me talking to myself so I really have no clue :-)
01-24-2008, 02:41 PM   #3
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Similar to this: DCRP Review: Sony Alpha DSLR-A100 ...then scroll-down between 1/3 and 1/2 way until you see the 1 large and 3 small pictures of the trees. Start reading about what's called "dynamic range optimizer" [DRO] 3 paragraphs before the pictures starting with "The dynamic range optimizer ..."

I imagine Pentax's implementation has some differences, but that best explains what it is.
01-24-2008, 02:54 PM   #4
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I think it does nothing you couldn't do with a PC-based RAW processor. It's nice to have it in-camera, though.

01-24-2008, 06:12 PM   #5
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QuoteOriginally posted by m8o Quote
Similar to this: DCRP Review: Sony Alpha DSLR-A100 ...then scroll-down between 1/3 and 1/2 way until you see the 1 large and 3 small pictures of the trees. Start reading about what's called "dynamic range optimizer" [DRO] 3 paragraphs before the pictures starting with "The dynamic range optimizer ..."

I imagine Pentax's implementation has some differences, but that best explains what it is.

that review mentions that it doesn't work on raw, so it is just a dynamic range compression as part of the jpeg conversion. I hope pentax's is not the same.
01-24-2008, 09:42 PM   #6
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QuoteOriginally posted by philmorley Quote
that review mentions that it doesn't work on raw, so it is just a dynamic range compression as part of the jpeg conversion. I hope pentax's is not the same.
The dynamic enlargement feature is jpg only. It is not magic, it is a simple way to tweak the jpgs for better DR.
The basic pros and cons are pretty well explained in this video
YouTube - Pentax K20D

Tim
01-24-2008, 10:07 PM   #7
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QuoteOriginally posted by Fototim Quote
The dynamic enlargement feature is jpg only. It is not magic, it is a simple way to tweak the jpgs for better DR.
The basic pros and cons are pretty well explained in this video
YouTube - Pentax K20D

Tim
bugger... I thought we were getting higher range
01-24-2008, 10:20 PM   #8
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QuoteOriginally posted by philmorley Quote
bugger... I thought we were getting higher range
The K20D gives you 1EV extra when in the extended dynamic range mode which equates to 2EV to play with... very film like.

01-24-2008, 10:37 PM   #9
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QuoteOriginally posted by codiac2600 Quote
The K20D gives you 1EV extra when in the extended dynamic range mode which equates to 2EV to play with... very film like.

but only if you shoot jpeg????????

pentaximaging specs list it as a playback filter, if so really it is only how it converts the raw file??? (hence the noise) and for people who shoot raw, it is a dead feature ???

hopefully I'm wrong here

Last edited by philmorley; 01-24-2008 at 10:46 PM.
01-24-2008, 10:44 PM   #10
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QuoteOriginally posted by philmorley Quote
but only if you shoot jpeg? you mentioned for raw yesterday?
In the beta model I was in Raw and this mode was selectable. AFAIK it takes it in RAW, but when I was able to shoot I was not allowed to personally play with files so I can only say that I could shoot it while in RAW mode.
01-25-2008, 12:25 AM   #11
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thanks chris, I'll just wait and see and hope
01-25-2008, 11:17 AM   #12
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QuoteOriginally posted by codiac2600 Quote
In the beta model I was in Raw and this mode was selectable. AFAIK it takes it in RAW, but when I was able to shoot I was not allowed to personally play with files so I can only say that I could shoot it while in RAW mode.
I may be on thin ice here. But I beleave that the settings you played with only affects the jpg embedded in the raw file. The rawfile itself is probably unchanged. Just a theory.

Tim
01-25-2008, 11:52 AM   #13
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Total speculation here, but I think there's more to it than just jpeg conversion. I suspect they take the picture with the sensor set at one stop slower iso, then boost the exposure of bottom half of the raw data to match the intended exposure. That would explain the additional stop of highlight detail, inability to work with ISO 100, and increased shadow noise.

If this is implemented before the raw encoding, it seems like it may be useful, but it will largely depend on how good their algorithm is and how much noise this sensor has in the shadows. But I'm getting way ahead of myself, I really don't know what they did or how effective it will be. Hopefully we'll all find out soon.
01-25-2008, 01:00 PM   #14
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Speculating

On the US video on youtube you could see that by switching the dynamics on you changed the ISO range. This leads me to believe they are doing something much more advanced than just adjusting the photo. I can belive it will not put it in RAW because t actually merges two photos and therefore they do not have enough processing power to do that in RAW. One way of doing this is as I specualted before (maybe this is not how they do it, but this is how it could be done) is this:

Camera measures that it needs to use F 4.0 and 1/100 sec

The camera then changes this exposure to F4.0 and 1/50 sec thereby over exposing the picture 1 step, but it will read the sensor after 1/200 sec, and then after the full 1/50. It will then have two photos one underexposed and one over exposed. The camera will then merge these two photos into one and store it (possibly only as JPEG).

If I am right here (and again I am just speculating) this means that they are able to read the sensor quickly. But when desining a new sensor I am sure they have taken future high FPS into account so maybe it is able to do what I just said. If this is how they are doing it, this can be developed with firmware upgrades and future hardware to actuallty give us more or less any dynamic range :-)

Pentax, if this is NOT how you do it; Think of this suggestion. Go ahead and patent it, would be nice to be mentioned as the inventor though ;-)
01-25-2008, 01:28 PM   #15
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Sample files of extended dynamic range

QuoteOriginally posted by walter Quote
Total speculation here, but I think there's more to it than just jpeg conversion. I suspect they take the picture with the sensor set at one stop slower iso, then boost the exposure of bottom half of the raw data to match the intended exposure. That would explain the additional stop of highlight detail, inability to work with ISO 100, and increased shadow noise.
Sounds very reasonable, and fairly easy to confirm if we only had a couple files (with vs without EDR) of the same subject to compare -- where did you see K20D photos that evidenced the three aspects you mention above? Their EXIF data might answer a couple other questions I had.

Incidentally, there's a much better way to get High Dynamic Range if you're willing to do a bit more work: take a set of up to 5 RAW shots using Exposure Bracketing at +-2EV. This will give you an additional 8EV (4 at each end.) Then run the set through a $99 post-processing utility called PhotoMatix Pro for both Windows and Mac:
http://www.hdrsoft.com/

Photoshop CS2 and CS3 also have HDR-related commands and tools that try to do the same thing.

The whole HDR concept and workflow is explained very well at:
http://www.naturescapes.net/072006/rh0706_2.htm
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