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Old Jan 7, 2009, 2:48 PM   #1
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the dynamic range option in the ISO menu
what is this for and when should you use it

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Old Jan 7, 2009, 3:14 PM   #2
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According to Pentax:"The K20D has added a dynamic-range expansion function, which allows the user to expand a dynamic range (or a range of gradation reproduction) while retaining the proper contrast to avoid white-washed areas. With an approximately 1EV expansion effect, it assures beautiful, rich-gradation images."

Essentially, this is designed to correct things like blown highlights invery bright or high-contrast situations. Say you're taking a picture ofyour house on a bright, sunny day. You set your exposure (shutter speed/aperature) for the best compromise you can - but some parts of the image might still be too brightand/or too dark - meaning your losing detail in those areas. The dynamic range control helps compensate to recover some of the detail or correct contrast. Hope I haven't confused you more.
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Old Jan 7, 2009, 3:30 PM   #3
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so would it be safe to say to leave it on



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Old Jan 7, 2009, 4:51 PM   #4
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Safe - as in "will it hurt the camera?" In those terms, it's fine to leave it on. But you might want to take a series of identical photos both with the dynamic-range function on and with it off. As with all things, there is no free lunch.

You may find leaving it on will have an effect on some images that you really don't want. I'm not saying it will ruin images completely. But perhaps you want a very strong "punchy" contrast. I suspect the dynamic range extender will soften contrast a bit.

But that's the great thing about digital photography: If you don't like the results, you can simply delete it and try again.
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Old Jan 7, 2009, 7:48 PM   #5
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Has anyone done an A/B comparison with the Dynamic Range feature turned on and off to compare what the actual results are?
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Old Jan 7, 2009, 9:11 PM   #6
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jelpee wrote:
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Has anyone done an A/B comparison with the Dynamic Range feature turned on and off to compare what the actual results are?
well... no.
But, now that I know about it... you can bet I will first chance I get!
:G
GW:bye:
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Old Jan 7, 2009, 9:23 PM   #7
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I've seen some comparisons on other cameras... notably the Olympus E-520. But this K20D test does have one comparison about halfway down the page:

http://www.dcresource.com/reviews/pe...eview/#dr_test

This isn't much... so, Goldwinger, your test would probably be appreciated.
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Old Jan 8, 2009, 12:15 AM   #8
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I've used it off and on, depending on conditions. It doesn't allow you to use 100 ISO with it - it's 200 and higher. It seemed to me that the camera then exposes for the highlights, and pushes more detail in the shadows, which increases the noise. You can do the same thing with software (lightening shadows). I tend to be sensitive to noise, so found I was running shots through noise reduction software at lower ISO levels than I would have normally, so I don't use it unless I specifically care about getting more detail in the shadows without blowing out the highlights. You may not notice the noise as much - best thing to do is try some sample, comparison shots.
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Old Jan 8, 2009, 10:05 AM   #9
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one strange thing i noticed is shinyfaces when using flash



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Old Jan 8, 2009, 9:38 PM   #10
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mtngal wrote:
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I've used it off and on, depending on conditions. It doesn't allow you to use 100 ISO with it - it's 200 and higher. It seemed to me that the camera then exposes for the highlights, and pushes more detail in the shadows, which increases the noise. You can do the same thing with software (lightening shadows). I tend to be sensitive to noise, so found I was running shots through noise reduction software at lower ISO levels than I would have normally, so I don't use it unless I specifically care about getting more detail in the shadows without blowing out the highlights. You may not notice the noise as much - best thing to do is try some sample, comparison shots.
My experience is similar to Harriet's. I will occasionally turn it on in a high contrast situation if I can't chimp my shot otherwise. Normally it is off. I normally lock my ISO to 100 because I find almost any amount of noise objectionable and utilizing this option seems to increase noise.

My experimentation with it is limited. I would describe the increase in dynamic range as noticeable but not really significant.

Tim
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