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Old Jul 12, 2006, 2:34 PM   #11
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Great shots! Very useable indeed, I say.

How did you use the histogram to overexpose? Is that some CS option I have yet to uncover? What are the benefits vs. just overexposing without considering the histogram?

thanks,
alex
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Old Jul 12, 2006, 2:54 PM   #12
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Hi Alex. What I meant was I checked the camera's histogram for each shot after taking a photo, and made sure it was a little overexposed, as you can back it off in processing when shooting RAW. Hence, you get less noise than if you underexpose and boost the exposure when processing. Try it, it works.....cheers......Don.


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Great shots! Very useable indeed, I say.

How did you use the histogram to overexpose? Is that some CS option I have yet to uncover? What are the benefits vs. just overexposing without considering the histogram?

thanks,
alex
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Old Jul 12, 2006, 3:10 PM   #13
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Some really nice photos here. I'll be buying a DSLR within the next year and I'm seriously considering Pentax. I'm waiting to see what the word will be on the K100.
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Old Jul 12, 2006, 3:14 PM   #14
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[align=center]good shots and good idea of minimizing noise.
Dan


thekman620 wrote:
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Hi Alex. What I meant was I checked the camera's histogram for each shot after taking a photo, and made sure it was a little overexposed, as you can back it off in processing when shooting RAW. Hence, you get less noise than if you underexpose and boost the exposure when processing. Try it, it works.....cheers......Don.
[/align]
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Pentaxchamp wrote:
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Great shots! Very useable indeed, I say.

How did you use the histogram to overexpose? Is that some CS option I have yet to uncover? What are the benefits vs. just overexposing without considering the histogram?

thanks,
alex
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Old Jul 12, 2006, 3:35 PM   #15
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thekman620 wrote:
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Hi Alex. What I meant was I checked the camera's histogram for each shot after taking a photo, and made sure it was a little overexposed, as you can back it off in processing when shooting RAW. Hence, you get less noise than if you underexpose and boost the exposure when processing. Try it, it works.....cheers......Don.



Thanks for the tip, I'll try that!

Kjell
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Old Jul 12, 2006, 4:46 PM   #16
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ditto. Great technique.

Ira
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Old Jul 12, 2006, 5:15 PM   #17
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Yes, basically you're shooting at a lower effective ISO speed if you overexpose. If you overexpose one stop at ISO 3200, you're just shooting at ISO 1600 from a shutter speed perspective if the aperture and lighitng are constant. ;-)

That's one reason noise is worse if you underexpose (because if you underexpose, you're effectively shooting at a higher ISO speed after you correct for it using software).

Likewise, overexposing will give you lower noise, just as if you used a lower ISO speed to begin with.

But, if you expose to the right, you can pull out a bit more dynamic range. Here's an article discussiog it:

http://www.luminous-landscape.com/tu...se-right.shtml


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Old Jul 12, 2006, 5:51 PM   #18
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Thanks for the tech info on that Jim. I'll have to try to expose 1 less stop at 1600, and see how they compare to the 3200 at 1 stop higher. Make a nice little project...cheers......Don.

JimC wrote:
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Yes, basically you're shooting at a lower effective ISO speed if you overexpose. If you overexpose one stop at ISO 3200, you're just shooting at ISO 1600 from a shutter speed perspective if the aperture and lighitng are constant. ;-)

That's one reason noise is worse if you underexpose (because if you underexpose, you're effectively shooting at a higher ISO speed after you correct for it using software).

Likewise, overexposing will give you lower noise, just as if you used a lower ISO speed to begin with.

But, if you expose to the right, you can pull out a bit more dynamic range. Here's an article discussiog it:

http://www.luminous-landscape.com/tu...se-right.shtml

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Old Jul 12, 2006, 6:11 PM   #19
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If you underexpose, you'll get higher noise, just as if you used a higher ISO speed to begin with, and dynamic range will suffer, too.

But, between ISO 1600 and 3200, it probably won't make much difference in Dynamic Range doing it that way (underexposing ISO 1600 to simulate higher ISO speeds).

That's because most cameras don't amplify the signal prior to the analog to digital converter for ISO 3200. Instead, they mulltiply the values in the data stream after the Analog to Digital Converter, just liking boosting Exposure would do in post processing shooting in raw. That's why ISO 3200 is referred to as "Extended" or "ISO Boost" in models that have it.

I sometimes use a -EV setting with Exposure Compenation to simulate a higher ISO speed (selecting something "in between" the one stop settings a camera has available for ISO speed to get faster shutter speeds without a full stop difference). But, for Dynamic Range purposes, it's usually best to lean towards overexposure instead.

Of course, once you reach the camera's maximum available ISO speed setting, that's the only choice you have if you want faster shutter speeds (deliberately underexpose to get faster shutter speeds if the aperture is already wide open). I do that from time to time at some of the local restaurants here with live music shooting with my KM 5D (underexpose ISO 3200 to get faster shutter speeds). Noise can get pretty nasty that way (just as if the camera had even higher ISO speeds available). But, noise is sometimes preferrable to motion blur. lol


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Old Jul 12, 2006, 7:06 PM   #20
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I don't cease to be amazed about how well Pentax does with high ISO settings. Definitly a plus for Pentax

TDN
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