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Olympus E-3 E-3 specific discussion.

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  #1  
Old 20th June 2008
senthil
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Interesting about ISO Noise

Today i meet my old teacher(Prof.) in the bus.
i have spent more than 1 hour with him...
Now he is doing Ph.D in Image Prossesing...i am asking some thing about photography...but he explains lot about image sensors....

Specially Noise in sensors....

here About ISO Noise in Digital Cameras....

Noise has a number of sources. Heat generated by the sensor might free electrons from the image sensor itself, thus contaminating the 'true' photoelectrons,that form the image, with 'thermal electrons' to give rise thermal noise. Another type of noise is caused by the amplification of the digital signal as we increase ISO. With an increase in ISO, the signal received by the diodes on the sensor is amplified. Unfortunately, as we amplify the signal, we also amplify the background electrical noise that is present in any electrical system.
Noise also occurs in low light because there is not enough light for proper exposure. The longer we allow the image sensor to collect a weak signal, the more background electrical noise it also collects. In many cases, the background electrical noise may be higher than the actual signal. These three types of noise combines to form the noise that you see in a digital image.
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Old 20th June 2008
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Re: Interesting about ISO Noise

All good info - and noise increases the more we process an image as image data is stretched, pixel errors are amplified, resulting in more noise, too.

But high ISO can still deliver good, relatively noise-free results. Here is an ISO 1600 image taken from a moving car at twilight on a Manila street:


It's not the full frame, either - so the image has withstood cropping well.

Ian
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Old 20th June 2008
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Re: Interesting about ISO Noise

Agree with the statement but the dark doorway area on the lower left of the picture looks very noisy to me. But hey.... I`m just paranoid cos I use an E1 and rely on NI at ISO 400 or higher!
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Old 20th June 2008
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Re: Interesting about ISO Noise

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Originally Posted by Scapula Memory View Post
Agree with the statement but the dark doorway area on the lower left of the picture looks very noisy to me. But hey.... I`m just paranoid cos I use an E1 and rely on NI at ISO 400 or higher!
I'm using my CRT monitor today as my laptop is still down and I'm using my desktop machine. The CRT does tend to mask noise. Or - do LCD panels amplify noise? I'll print the image and let you know

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Old 20th June 2008
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Re: Interesting about ISO Noise

Quote:
Originally Posted by Scapula Memory View Post
Agree with the statement but the dark doorway area on the lower left of the picture looks very noisy to me. But hey.... I`m just paranoid cos I use an E1 and rely on NI at ISO 400 or higher!
Now at home and looking at the image using Julia's laptop (17" 1440x900 res) and you have to view the screen at rather unrealistic angles to make the noise in that dark area stand out

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Old 20th June 2008
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Re: Interesting about ISO Noise

Ian -

You could have used one of those cables to send your pic back.

Regards. Barr1e
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Old 20th June 2008
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Re: Interesting about ISO Noise

Quote:
Originally Posted by Ian View Post
Now at home and looking at the image using Julia's laptop (17" 1440x900 res) and you have to view the screen at rather unrealistic angles to make the noise in that dark area stand out

Ian
Ok, viewing my 17 " laptop at the same resolution ( Horrible Vista and a true life sceen calibrated with Quickgamma ) and the image looks terribly noisy in the area mentioned and not at any strange angle. But this is 1600 ISO..... cannot go there with E1, thing is Ian it is definately there on your E3.
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Old 20th June 2008
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Re: Interesting about ISO Noise

But it's only in the darkened doorway which is surely a passive part of the image and relatively unimportant. It could be selectively darkened a tad more which should make it even less important. I'd be more worried if noise was that noticable in the main subject areas. I wonder what a print of this scene from ISO 1600 colour film would look like?
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Old 21st June 2008
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Re: Interesting about ISO Noise

I disagree. It is also prominent on the tyre in the foreground, the red of the coke sign and the guy in the blue shirt and dark trousers. In fact looking at the image across the entire range shows it as being quite noisy and consistently so throughout. Not sure why you would need to compare to colour film?
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Old 21st June 2008
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Re: Interesting about ISO Noise

Quote:
Originally Posted by Scapula Memory View Post
I disagree. It is also prominent on the tyre in the foreground, the red of the coke sign and the guy in the blue shirt and dark trousers. In fact looking at the image across the entire range shows it as being quite noisy and consistently so throughout. Not sure why you would need to compare to colour film?
Well, those of us old enough to remember film know just how bad it was at speeds as high as 1600 ISO; large, blocky intrusive grain, lack of definition, desaturated, muddy colours. ISO 50 was the norm for me; ISO 100 was a fast film. I very occassionally used ISO 400 in challenging conditions and if that wasn't enough gave up.

So to me, rightly or wrongly, film is still the standard against which digital is judged. And to get this sort of quality at ISO 1600 is amazing. It's not perfect by any means, but it is useable and can of course be processed to remove some of that noise.

I guess it's all a matter of perception. What is acceptable to one person may be worse than useless to another.
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Old 21st June 2008
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Re: Interesting about ISO Noise

Quote:
Originally Posted by Scapula Memory View Post
I disagree. It is also prominent on the tyre in the foreground, the red of the coke sign and the guy in the blue shirt and dark trousers. In fact looking at the image across the entire range shows it as being quite noisy and consistently so throughout. Not sure why you would need to compare to colour film?
Mmmmm... I'm not seeing the noise as prominently as you describe, either on the CRT or the 17 inch laptop LCD screen.

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Old 21st June 2008
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Re: Interesting about ISO Noise

I can see it too but there seem to be some compression artifacts (is that the correct term?) present as well.

That said it is ISO1600 so I'd expect to see noise

It's certainly a vast improvement on ISO1600 film.........

......... however it has to be compared to the current competition such as the D300/a700 etc.
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Old 21st June 2008
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Re: Interesting about ISO Noise

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Originally Posted by R MacE View Post
I can see it too but there seem to be some compression artifacts (is that the correct term?) present as well.

That said it is ISO1600 so I'd expect to see noise

It's certainly a vast improvement on ISO1600 film.........

......... however it has to be compared to the current competition such as the D300/a700 etc.
But it's all relative. The High ISO performance of the D300 is often used as an example of what's currently state of the art, but only this week Amateur Photographer concluded in a head-to-head comparison that the Canon 5D was still significantly better.

So anyone with an overiding priority for the best possible high ISO performance would do well to eschew the D300, the E3 and in fact any DSLR with less than a 35mm full frame equivalent sensor. So that leaves you with the choice of a couple of completely unaffordable top end Canons, an almost as expensive Nikon D3 - or the relatively humble and quite long in the tooth Canon 5D.

Whether you would rather have a 5D than an E3 for all round photography is a decision only each individual photographer can make.
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Old 21st June 2008
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Re: Interesting about ISO Noise

I agree it is all relative.When I shot film I never ventured beyond Iso(ASA)400.On my E1 I would never get the definition that I get from the E3 at ISO1600.

ie




Yes there is some colour noise in the dark areas but I dont find it a problem.

Ps even with a little sharpening
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Old 22nd June 2008
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Re: Interesting about ISO Noise

Quote:
Originally Posted by Zuiko View Post
But it's all relative. The High ISO performance of the D300 is often used as an example of what's currently state of the art, but only this week Amateur Photographer concluded in a head-to-head comparison that the Canon 5D was still significantly better.

So anyone with an overiding priority for the best possible high ISO performance would do well to eschew the D300, the E3 and in fact any DSLR with less than a 35mm full frame equivalent sensor. So that leaves you with the choice of a couple of completely unaffordable top end Canons, an almost as expensive Nikon D3 - or the relatively humble and quite long in the tooth Canon 5D.

Whether you would rather have a 5D than an E3 for all round photography is a decision only each individual photographer can make.
Absolutely, don't get me wrong I'm perfectly happy with the E-3, the amount of times I need ISO1600+ I could count on the thumbs of one hand and even then it depends on what the images are going to be used for. I wouldn't swap the E-3 for a D3/5D as I certainly don't need the extra weight/bulk any more than I need the high ISO performance.

In fact I'd actually like an E-410/420. Consider the weight advantage of a 410, 9-18, 14-42, 70-300 over a D3/5D + 18-36, 28-84 and 140-600. You'd really have to be using ISO1600+ quite a bit to make carrying all that weight worthwhile.
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