Sensors

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DaveW
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Sensors

Post by DaveW »

There still seems some confusion as to what sensor size and pixel site size due to too many Megapixels on a too small sensor can have on photographs.

"Packing megapixels

You may have heard of the “megapixel myth,” which states that the more megapixels your camera can pile on its sensor, the better your images will be. This is not true. You don’t just want more pixels, but rather the right number of pixels relative to the size of the sensor. And the right number depends on what you intend to do with your photos. For massive cropping or extra-large printing, additional resolution is useful. For online sharing or conventional printing, resolution is less important. Trade-offs include large file sizes and the need for more processing power to handle high-res photos, versus noise in lower-resolution images.

Smaller sensors that cram pixels together tend to have poorer low-light performance and produce noisy artefacts."


More Megapixels on the same sized sensor are not always better, be it a Smartphone or DSLR. A good article on sensors here:-

http://www.techhive.com/article/2052159 ... r-all.html" onclick="window.open(this.href);return false;
Onzuka
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Re: Sensors

Post by Onzuka »

Yes, an interesting read, Dave. I've known for years not to be fooled by the marketing mens' dash for megapixel count. I'll continue to use my 2004 technology Olympus C8080 wide zoom with it's 2/3" sensor and 8 megapixels. If I fail to get a good picture, it's always my fault, the camera is very capable.

Steve
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SnowFella
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Re: Sensors

Post by SnowFella »

Latest hype there would be nokias latest camera phone with 41 megapixels. My old dslr is a mere 14 or so MP but I'm quite sure it would have any camera phone for breakfast any day of the week!
DaveW
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Re: Sensors

Post by DaveW »

There are other views on high megapixel sensors though:-

http://photographylife.com/the-benefits ... ion-sensor" onclick="window.open(this.href);return false;

http://www.billmajoros.com/photoalbum/c ... ified.html" onclick="window.open(this.href);return false;

http://www.mdavid.com.au/photography/pixeldensity.shtml" onclick="window.open(this.href);return false;

What really matters with any camera though are the results you get in the final image and if these are good enough for your purpose?
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Snowcat
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Re: Sensors

Post by Snowcat »

SnowFella wrote:Latest hype there would be nokias latest camera phone with 41 megapixels. My old dslr is a mere 14 or so MP but I'm quite sure it would have any camera phone for breakfast any day of the week!
Even more! The old 4MP (!) camera SONY F-707 takes MCUH better images then any of modern smartphones. Megapixel number is a pure marketing, nothing more.

P.S.Well, I have Sony A-77, which was first APS-C size camera to have 24MP, true :) But it's a great camera not because of megapixels... Even quite the contrary - due to high MP count it has rather poor low noise performance, so if they'd made it 14MP it would be better. Yet all the tasties in it made me forget about noise, especially as there is a way to overcome it :)
DaveW
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Re: Sensors

Post by DaveW »

Problem with most noise reduction, either in camera or in post processing, is it reduces resolution. You sometimes wonder if the extra resolution gained from more but smaller megapixels is negated by the increased noise reduction needing to be applied so the image gets no better?
Ron43
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Re: Sensors

Post by Ron43 »

DaveW wrote:Problem with most noise reduction, either in camera or in post processing, is it reduces resolution.
That would depend on the software you use for noise removal. If you use a top quality software the resolution is not reduced.
DaveW
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Re: Sensors

Post by DaveW »

Is there any "non-destructive" noise reduction software though Ron?

From what I understand noise reduction software simply softens the image. Most then simply pseudo-sharpen it again afterwards. I say pseudo-sharpen it because you can never reclaim information once lost in an image, only simulate it:-

http://photographylife.com/photo-noise- ... n-tutorial" onclick="window.open(this.href);return false;

In all the "mouse over" examples in the above link I notice feather detail on the head is reduced after noise reduction is applied and sometimes also in the eye.

"The only way to add more pixels to a chip of a given size is to make the pixels smaller. But, as the pixels become smaller they are less able to capture photons, and therefore their signal to noise ratio decreases. (All electronic circuits have inherent noise. The more signal (photons) there is, the lower the noise is relative to that signal).

This is a bit of a moving target. Chip makers and camera makers continue to improve their circuitry and noise reduction capabilities. But the laws of physics can't be denied. And, any and all technologies used to reduce noise on new designs of chips with smaller pixels can equally be applied to those with larger pixels. So while absolute improvements are being seen, relatively speaking the gap between them remains roughly the same."


http://www.luminous-landscape.com/essay ... sign.shtml" onclick="window.open(this.href);return false;
Ron43
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Re: Sensors

Post by Ron43 »

Viewing at 100% or larger will show soft edges even before noise removal. For me I find that the majority of noise is usually in the blue channel and will remove it in the blue channel only in Photoshop Elements. Perhaps I'm missing something here because I rarely view images at 100% on my computer and when I print them they are sharp. One of the biggest problems is viewing at too high resolution on the computer or too close when printed. I do agree with the small sensors and cramming more pixels in causing problems, but that's how the manufacturers scam the public. I still have a 2 meg camera and it takes awesome photos, but I don't use it much anymore.
DaveW
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Re: Sensors

Post by DaveW »

It will be interesting to see what happens with the Foveon sensor where no softening is needed to prevent moiré patterning, as opposed to the Bayer type sensors most camera manufacturers now use. The Foveon uses three layers of sensors, one for each colour, just like colour film:-

http://www.dpreview.com/articles/726283 ... er-sensors" onclick="window.open(this.href);return false;

It seems Canon may be dipping it's toe in the water with their rumoured 75+ megapixel sensor, though there is a question as to whether this is marketing hype and they are counting all the megapixels in the layers which may simply be combined to produce a 25 megapixel image, sort of a form of pixel binning?

http://petapixel.com/2013/07/23/canons-" onclick="window.open(this.href);return false; ... er-sensor/
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