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Old Aug 20, 2006, 4:10 PM   #11
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Thanks all for commenting thesetrial pics!
Genece, regarding tips, I can just tell how these were handledas itwas my own first trial.I wanted to testa realistic way to often handle low light situations withoutchanging a lot of camera settings andwithout any advanced post-processing(or doI need the FZ50 and its ISO1600 capabilities?).

So, all camera settings (contrast,noise reduction, etc) are standard. The only thing I changed were ISO to 400 and exposure to -2. For those that want to optimize, I guess you could get rid of more noise by settingnoise reduction to high and the othersto low but then it becomes a lot of settings to remember and set backwhen it's time for 'normal' shooting.

ThenI used freeware Neat Image with default settings (the images were auto-profiled, no changes to any filter).Brightness and contrast were raised, also within Neat Image (if you use any photoediting program, it'seven easier withan 'auto level' or 'auto contrast'). Done!
I'm sure it can be done better by trying different settings in Neat Image which could be worth it as these could be saved and quickly used the next time. However, I'm not there yet! If someone is, I would be happy to know!
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Old Aug 20, 2006, 8:24 PM   #12
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PeHa wrote:
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ISO400 andexposure compensation to -2 which means exposure settings equivalent to ISO1600.
Hi, maybe it is just me .. but I don't get why ISO400 combined with EV compensation of -2 should result in ISO1600 equivalent?

I thought with ISO1600 you have the ability to shoot with shorter shutter time and still get a bright image. Something thats useful in the dark.

But ISO400 is 2 steps less light-sensitive than ISO1600. If you want to achieve as bright images as with ISO1600 you would have to increase exposure compensation to +2, I think. That of course would increase the shutter time and thus would not really be equivalent but in brightness. It would be more blurred than with real ISO1600.

I would say, it can't be faked.

Nevertheless, your pictures are nice
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Old Aug 20, 2006, 8:39 PM   #13
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Leberwurstsaft wrote:
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I would say, it can't be faked.
The Original Poster is using the correct technique to simulate a higher ISO speed.

Although I don't think the images were brightened enough (they still look a bit too dark for correct exposure, and when you brighten them, noise will show through more).

If you underexpose ISO 400 by 2 stops (as a -2.0 EV Setting will do with exposure compensation), then brighten the photo later using software to counteract the underexposure, for all practical purposes, you're shooting at ISO 1600.

This can be a useful technique when your shutter speeds are not fast enough in low light (since the autoexposure algorithms are going to shoot with the aperture wide open anyway in low light).

So, when shooting at ISO 400, if you underexpose by one stop (-1.0 EV Setting with Exposure Compensation) when shooting in Auto or Aperture Priority mode in low light, you'll get shutter speeds twice as fast (the same as you would get by using ISO 800 if it had it).

If you underexpose by two stops (-2.0 EV Setting), you'll get shutter speeds four times as fast (the same as you would get by using ISO 1600 if it had it).

The downside of this technique is higher noise levels after brightening the image with software (just as if you'd used a higher ISO Speed to begin with) and reduced Dynamic Range.

Some camera models with an "extended" or "boosted" ISO speed choice are doing the exact same thing. Basically, instead of amplifying the signal from the sensor prior to the analog to digital converter, they're only multiplying the rgb values associated with each pixel to simulate a higher ISO Speed in the image processing pipeline -- which is basically the same thing you're doing when you deliberately underexpose and use software to brighten an image later.

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Old Aug 21, 2006, 5:08 PM   #14
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Thanks foryour comments Leberwurstsaft and many thanks for clearifying the subject Jim!

However, Idon't want to brighten the images more, never mind the noise! It was quite a dark place and the images as they're presented here look just as I recall that my eyes saw them. :shock:

Theyare shot in JPG Fine (8MP). I've alsotriedshooting RAW with the sameexposure settings, then convertedthe imagesto JPG andfinally ran them through Neat Image butwith much worse results.Neat Image (at default settings) obviously givesmuch better results if the input images have had that first step of noise reduction madeby the camera.
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Old Aug 30, 2006, 1:50 AM   #15
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Hi Peha,

Beautiful pictures. Very interesting process. Thank you so much for sharing your great technique for getting these kinds of shots in low light.


style="BACKGROUND-COLOR: #000000"All three are wonderful, and my favorite is the boa on the limb. Very nice!

style="BACKGROUND-COLOR: #000000"Teree
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Old Aug 30, 2006, 2:45 AM   #16
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Thanks Teree ;-)
Yes, it's nice to explore the cameraand hopefullyfind solutions to some difficult situations!


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Old Aug 30, 2006, 12:26 PM   #17
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I dont get the point of using ISO 400 and -2exp.comp.
Youcould've insreasedthe shutter speedand used ISO400.
If in fact ISO400 and -2 exp.comp. gives you ISO1600, then
the FZ30's ISO is equivalent to the Fuji S9000's, and the only
advantage it has is a wider lens and a slightly bigger sensor.

BTW, let's say you use ISO1600 and set -2 exp.comp., does
that mean you get ISO6400?


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Old Aug 30, 2006, 3:01 PM   #18
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have you tried printing it out?


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Old Aug 30, 2006, 5:01 PM   #19
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Remember I'm not an expert on this, it was just a trial :G

Using this technique requires you to do postprocessing (brightening is a must, probablynoise reduction as well) so it's not like a camera with ISO1600 supported as the Fuji S9000. But as Jim writes above, that's exactly what some cameras with hi ISO support do, the difference here is just that you do it yourself afterwards.

Having a camera that can be set to ISO1600 andexposure compensation set to -2 will give exposure settings equal to ISO6400, yes, but the image will be too dark.Simulatinga trueISO6400 image also requiresbrightening afterwards. However,brightening a dark image will not give the same dynamics in showing different levels as acorrectly exposed image, that'sa drawback but as here it can be acceptable.

I've printed the turtle at standard 4x6" size, looks just fine!
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