G7 sensor size up to task of 10 megapixel ?

Virvatulet · Sep 21, 2006

Unfortunately, reducing image size by resampling is not as effective cancelling the noise as it would be to use same native resolution CCD sensor, all other things kept equal. Not to mention better dynamic range of larger photodiodes and potential wells (internal CCD structure).

In your example the pixels are smaller on the 10 mp CCD, therefore more noise per pixel and lower dynamic range than with the 5 mp CCD (larger pixels). My well educated guess would be that the resampled 5 mp image from the 10 mp CCD would be very close the same quality as the 5 mp CCD image, assuming advanced noise cancellation filtering made before high quality resampling.

But why not native 5 mega pixels in the larger CCD, that would yield much better image quality than the resampled image?

Selecting smaller image size is neither the solution nor substitution for real native SNR performance.

trizt said:
(and if someone can tell me why the size of the CCD is given as "1
over x" I can tick one of my mystery boxes

A good explanation here:

http://www.dpreview.com/learn/?/Glossary/Camera_System/sensor_sizes_01.htm

-Virvatulet

Peter G · Sep 21, 2006

imbsysop said:
IMHO that is a very simplistic statement .. if so plse kindly
explain why noise levels in the new ICX 1/2.5 Sony sensors for
example offer a very useable ISO400 without practically any visible
detail loss whereas a G6 with an 1/1.8 sensor has a completely
worthless ISO400 (compares more or less with ISO1000 on the newer
sensors) .. noise reduction is not magic .. it is mathematics ..

Show me some proof. Because if you bothered to look at the thread below its shows that this is not the case at all.

trizt · Sep 21, 2006

Virvatulet said:
But why not native 5 mega pixels in the larger CCD, that would
yield much better image quality than the resampled image?

Well, if I was to design my own camera I would not put in a 10 MP CCD, but I'm not in the business so I have to make a choice. I think that the G7 would be the best choice for me but it has a 10 MP 1/1.8" CCD. The A710 is similar in many ways and much cheaper and has a 7 MP 1/2.5". No doubt will the IQ be better in the G7 (or Canon is doing something terribly wrong), but is it worth the price?

Thanks!

Tobias

Peter G · Sep 21, 2006

From the link I posted above: 5MP camera vs 10MP downsized. You judge.

http://forum.computergames.ro/attachment.php?attachmentid=138843&d=1158484117.jpg

CameraCuckoo · Sep 21, 2006

Tetsuro said:
The sensor is bad, will require heavy PP by the CPU in the camera.
Anyway that's the 'future' (more MP on tiny sensors) so must accept
it.
--
Alessandro

Your in-depth critique ('bad') of this relatively new sensor is quite enlightening - so many thanks.

Some evidence please?

Have you seen it in action? Have you seen the real-life output of the G7?

Manufacturers such as Canon don't release cameras unless they are sufficiently happy with the output so I don't predict being able to see much of a difference between this sensor and the 7.1Mp (which, don't forget, is smaller 1/2.5" than the G7 10Mp 1/1.8").

trizt · Sep 21, 2006

that was pretty clear

why are they making it so hard to select camera??? well I don't give up until the review comes.

Virvatulet · Sep 21, 2006

imbsysop said:
IMHO that is a very simplistic statement .. if so plse kindly
explain why noise levels in the new ICX 1/2.5 Sony sensors for

I think Peter means more the noise per pixel. Anyhow, the point is that every innovation and advancement in CCD technology has been systematically distrained by increasing pixel density in P&S cameras. I would say that the current “progress” in ISO sensitivity is in fact largely accomplished by means of advanced signal processing i.e. aggressive advanced filtering.

What makes comparison of different CCD-chips very difficult is that the image file is always a result of mathematical processing, this is emphasised when we are talking about different generations, like G6 sensor versus the current offering. Also, it should be kept in mind that the new Canon cameras have lower actual sensitivity at selected ISO setting.

Method should be developed for measuring quantitatively effective pixel level noise or resolution corrected noise. Then things would start looking pretty ugly for many newer P&S digicams.

-Virvatulet

Robert Deutsch · Sep 21, 2006

The A610 shot is at ISO400, whereas the A640 is at ISO800. You have to compare shots taken at the same ISO.

Bob

trizt · Sep 21, 2006

Robert Deutsch said:
The A610 shot is at ISO400, whereas the A640 is at ISO800. You
have to compare shots taken at the same ISO.

Another thread explained that Canon is adjusting their ISO setting so that old 400 is comparable to new 800. I guess that that is why the light in the scene is similair with the same shutter and aperature settings, or is that adjusted? (or is that not a correct conclusion - i'm a newbie...)

Robert N · Sep 21, 2006

trizt said:
that was pretty clear why are they making it so hard to select
camera??? well I don't give up until the review comes.

If you really need high ISO, you should consider a DSLR and a couple of light and fast primes. DSLRs are very cheap nowadays and you can also get great (used) lenses for a bargain. One of my favourite lenses is a Sigma 24mm 2.8 II (€80 used). Add a 50mm 1.8 (about €100 new) and you have a razor sharp and cheap combo to start.

--
Regards,

Robert

Robert N · Sep 21, 2006

Robert Deutsch said:
The A610 shot is at ISO400, whereas the A640 is at ISO800. You
have to compare shots taken at the same ISO.

Bob

ISO 400 is in reality ISO 800, look at the shutterspeed.
--
Regards,

Robert

trizt · Sep 21, 2006

My first selection criterion is size and the G7 is about as large as it can get. I can squeeze it into a pocket. That's still hard with a dSLR. My long term plan is to find the time to spend more time photagraphing, then I will by a dSLR. Now, I'm after something that offers me some more settings to play with so that I can learn. High ISO may be more of an obsession than a requirement... I have to think about that for a while...

Thanks!

ShutterNot · Sep 21, 2006

Soryy ... no I don't.
--
Shutter Nut

Virvatulet · Sep 21, 2006

ShutterNot · Sep 21, 2006

Because they rely so much on processing the signal is also propably why they don't include the RAW format anymore in the newer cameras. They need to process the signal agressively. I'm sure the mathematics behind this is great.

That is my worry about the current sensors they are putting in these new cameras. They are relying to much on the software in the cameras to massage the pictures. There doesn't seem to be any real advances in the sensors. If there are advances, I haven't heard about it.

--
Shutter Nut

imbsysop · Sep 21, 2006

Peter G said:
Peter G said:

IMHO that is a very simplistic statement .. if so plse kindly
explain why noise levels in the new ICX 1/2.5 Sony sensors for
example offer a very useable ISO400 without practically any visible
detail loss whereas a G6 with an 1/1.8 sensor has a completely
worthless ISO400 (compares more or less with ISO1000 on the newer
sensors) .. noise reduction is not magic .. it is mathematics ..

Click to expand...

Show me some proof. Because if you bothered to look at the thread
below its shows that this is not the case at all.

I own both a G6 and a Sony H5 so I know exactly what the noise levels at ISO400 are for these sensors, what more "proof" do I need ? besides consulting the ICX sensor data sheets of course ..

--
if needed, email me at : [email protected]
Horum Omnium Fortissimi Sunt Belgae !
(CanFT-QL)CanG6SonH5CanA520-M3358-DH1758

Virvatulet · Sep 21, 2006

ShutterNot said:
I'm sure the mathematics behind this is great.

It is incredibly beautiful!

-Virvatulet

Peter G · Sep 21, 2006

imbsysop said:
imbsysop said:

imbsysop said:

sensors) .. noise reduction is not magic .. it is mathematics ..

Click to expand...

Show me some proof. Because if you bothered to look at the thread
below its shows that this is not the case at all.

Click to expand...

I own both a G6 and a Sony H5 so I know exactly what the noise
levels at ISO400 are for these sensors, what more "proof" do I need
? besides consulting the ICX sensor data sheets of course ..

Yes and as you stated. Noise reduction is not magic. Sony just cranked up the software noise reduction and mushed out detail in the process.

Quoting the H5 review:

"... thanks to Sony's much heavier noise reduction, which produces a superficially cleaner-looking image, but one with slightly more obvious noise reduction artefacts. It's a matter of taste, but for me the S3 IS has the edge thanks to Canon's less heavy-handed approach to noise reduction."

Instead of noise you get mush. Both unacceptable to me.

Virvatulet · Sep 21, 2006

http://www.dpreview.com/reviews/canong6/page14.asp

ShutterNot · Sep 21, 2006

Everytime somebody compares the 610 with another camera, I look at the detail in the grey shaddow area. The 610 delivers a tad more detail.

Imagine what that translates to in the overall effect.

--
Shutter Nut

G7 sensor size up to task of 10 megapixel ?

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