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Old Feb 18, 2008, 12:00 PM   #11
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@Daniel

I have a *ist DL2 but your images doesn't "feel" very familiar. How did you shoot them? In JPEG? It almost looks as if there was some kind of post-processing... strange. I'll have a go, too. Noise level isn't very high compared with what I work on mostly

Th.
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Old Feb 18, 2008, 2:00 PM   #12
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thkn777 wrote:
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@Daniel

I have a *ist DL2 but your images doesn't "feel" very familiar. How did you shoot them? In JPEG? It almost looks as if there was some kind of post-processing... strange. I'll have a go, too. Noise level isn't very high compared with what I work on mostly

Th.
Wow you are very observant.
I did straight jpeg with nr on too - in a way pp. I hardly do raw even now. The NR of DL may (?) be different from the NR in K100d or K10D. That could be one of the key of noise difference re the samples above. But that much difference? That is the reason why I suspect Nikon did quite a bit tweaking either in firmware or software


Daniel

psp http://www.pbase.com/danieltong/image/89627920/original another DL iso 1600 shot with FA100mm macro at F2.8 . As I said I had a whole pile of image proving that it is better off NOT to underexpose at 1600 as underexposure at iso 800 causes more noise.
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Old Feb 19, 2008, 1:14 PM   #13
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danielchtong wrote:
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Wow you are very observant.

Thanks



Here are some tests, that might explain something of the "magic" you are asking about.

#1 - ISO200, ISO800, ISO1600, ISO3200test shots. RAW developed with pentax photo lab without noise reduction, without WB, all sliders in middle position



As you can see the noise level goes up with the ISO.

#2 - JPEG high contrast vs. low contrast @ ISO1600



Since you said, that you took the pictures in JPEG mode, I include a test with different contrast settings, since I noticed that this makes quite a difference. JPEG fine shots, I only modified the contrast in-camera settings from +2 (upper) to -2 (lower).

#3 - now the same ISO series from #1, but in JPEG fine with contrast +2 settings



Quite a "wow" effect if you ask me. Free high quality in-camera noise reduction Drawback: can you live with the +2 contrast setting? If yes you can take way more pictures in a higher ISO setting.

#4 - details of your photos



I wouldn't consider the shadow areas at the jacket very noisy - ok? They seem almost noise-free to me and also a closer look with some magnification show this behaviour. Why do you think noise is much stronger in the ISO800 shot? Please inspect the original pictures and you'll find, that the ISO800 shot has fine details with low noise too - I believe it's more a feeling of more noise here... "perceptive noise" to say so. Watch the face of the ISO800 man and the actors - you'll see a lot of detail and not those huge noise differences...

Regards,
Th.

P.S: Please note that wemostly talked about the black areas here... noise levels and "feeling" is very different at other colors / shades of grey. Try those tests for yourself!
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Old Feb 19, 2008, 4:52 PM   #14
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Another quick "demo"

Using a dark background and that piece of sugar and the Eiffel-Tower statue I created a similar situation to your concert shot and took photos in ISO3200, JPEG fine, sharpness-2, contrast+2, WB=indoor.

#1 - Resized for forum use it looks like this:



#2 - and here are some 100% details:



No postprocessing but the resize in #1. That's straight from the camera. Astonishing, isn't it?

There certainly is quite some noise in that ISO3200picture, but you don't NOTICE it that much. It really helps, that you don't have color noise in the black areas (background), only the reflections have some color noise. Postprocessing would be able to reduce noise a lot without stealing too much detail... but that's not what we are talkin about here.

What do you say?

Th.

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Old Feb 19, 2008, 5:38 PM   #15
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thkn777 wrote:
Quote:

Here are some tests, that might explain something of the "magic" you are asking about.

#1 - ISO200, ISO800, ISO1600, ISO3200¬*test shots. RAW developed with pentax photo lab without noise reduction, without WB, all sliders in middle position



As you can see the noise level goes up with the ISO.

#2 - JPEG high contrast vs. low contrast @ ISO1600



Since you said, that you took the pictures in JPEG mode, I include a test with different contrast settings, since I noticed that this makes quite a difference. JPEG fine shots, I only modified the contrast in-camera settings from +2 (upper) to -2 (lower).

#3 - now the same ISO series from #1, but in JPEG fine with contrast +2 settings



Quite a "wow" effect if you ask me. Free high quality in-camera noise reduction Drawback: can you live with the +2 contrast setting? If yes you can take way more pictures in a higher ISO setting.



I have PSP version 8 which has the NN2 pluggin. I know I can crank up contrast, to a certain extent, to get rid of quite a bit of noise. You have proved beyond doubt that was the case.




Quote:

#4 - details of your photos



I wouldn't consider the shadow areas at the jacket very noisy - ok? They seem almost noise-free to me and also a closer look with some magnification show this behaviour. Why do you think noise is much stronger in the ISO800 shot? Please inspect the original pictures and you'll find, that the ISO800 shot has fine details with low noise too - I believe it's more a feeling of more noise here... "perceptive noise" to say so. Watch the face of the ISO800 man and the actors - you'll see a lot of detail and not those huge noise differences...

Regards,
Th.



Pict#1 has most of the non subject area underexposed (just happened that way) thus it has quite a bit of noise. I would stress it is in the non-subject area though. Again that contribute to the perception that it is overall noisy.



Quote:

P.S: Please note that we¬*mostly talked about the black areas here... noise levels and "feeling" is very different at other colors / shades of grey. Try those tests for yourself!
You have done great service for letting forum members know the process.

It would seem the abnormality (iso 800 noisier than iso1600) was due to post-processing as done in camera (from raw to jpeg)

I am to experiment with more indoor shots (with lousy weather outside anyway) to test out some tough dim shots.

Thanks a million for your input

Daniel
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Old Feb 19, 2008, 6:24 PM   #16
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Th

Great information here, you have illustrated the impact of ISO in both exposure accuracy and image format. If I shoot RAW and try to optimize the exposure I should get less intrusive noise (I hope I have that right).

Ira
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Old Feb 20, 2008, 2:50 PM   #17
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@Daniel
You are welcome and thanks for your kind words.

@Ira
I don't know if I really understood what you said... but you can use the same "trick" in the RAW converter. It's not the same image you'll get when shooting RAW and postprocessed and then compared with the in-camera JPEG's but the same mechanics apply here, yes.

I used almost the same setup and took a RAW photo, then postprocessed in Pentax Photo Lab. Color Noise reduction = 100%, no other noise reduction, indoor WB, sharpening -2.

#1 - contrast+2, saturation=0, resized



#2 - contrast-2, saturation+2, resized



(I went for some more saturation to come closer to #1 at least a bit). I can provide details if necessary, but even with these resized images you'll notice to huge difference in noise level. Of course these are two different images and the low contrast shot revealed some details even in the black background that you won't notice in the high contrast shot. It's a question what picture you are after.

Now both shots don't look like the original - there might be some intelligent postprocessing ways tocombine two pictures, that were converted with different contrast/noise settings, in a way, that a more "natural" photo with less noise is produced. Ideas welcome.

Anyway - I think this is really important to know for people that do available light photography (i.e. concert shots) - you are really able to use that ISO1600 and ISO3200 to some extend! Btw. - most people I meet tell me even ISO800 shots on modern dSLR have way too much noise (because THEY used a photo editor and pixel peeped and sawISO800 noiseand feel cool now) and rise more than one eyebrow if I tell them that ISO1600+ will give decent pictures in some(!) cases if you do it right. :lol:They don't even TRY to explore their (expensive) equipments features even if you poke their noses into obvious facts. Oh well.

Happy snapping, regards,
Th.


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