2 cameras same sensor but more mega pixel

[BowerR64]

How does this work?

Im seeing the same sensor being used on all these cameras but they are growing in mega pixels by the day. How does this work exactly?

If say i have a camera with 5 mega pixel and one with the same sensor but its 7.1 mega pixel will these 2 have the same file size if they are set to the same image size? say 2592 x 1944 resolution on both cameras.

Will the file sizes be the same or will one be larger?

Say A60 and A70, or A510 A520, or even the A610 and A620

[Robert Besen]

Why do you think the cameras have the same sensor? It seems unlikely to me that a 5 and a 7.1 megapixel camera would use the same sensor.

[Riley]

its possible they are the same size sensor ie 1/2.5"
but one camera might be set at a lower resolution

[gmtech79]

If you have 2 camera's each with different megapixel's the file size will be different. Going off of your example a 5 megapixel camera would have a resolution of about 2500 x 2000 and a 7 megapixel camera would have a resolution of about 2900 x 2400 roughly. I know that many camera's sensor's are the same physical size but they can pack more pixels on to them thus giving them more resolution but yet they also pick up more noise.
As far as file size if both camera's are set to the same compression and you shoot the exact same scene the 7 megapixel camera will have a larger file size as well as a larger image size.

[BowerR64]

Why would the 7.1 be larger?

Why is there more noise? because its interpolated?

When i say the same size i mean the same resolution size, both cameras will use the same compression settings like fine detail.

They both use the same processors and stuff digic 2 and everything else. The only difference is the sensor sizes.

How can they pack more mega pixels into them?

I just think they are cheating with the mega pixel claim using the same sensor over and over but using software to stretch the images little by little.

[CptOfGondor]

Sensors used are the same size yes but there are more 'pixels' crammed it.

say you took a square of w/e size. Divide that into a million pixels. Next year you divide each pixel into 4 equal but smaller pixels and now you've got 4 MegaPixels. Theres more noise because each of those pixels is receiving less light because they are alot smaller and more easily influenced by the pixels around it.

[BowerR64]

Would it be possible to look at a sensor with a microscope or somthing and see the difference?

What if the the sensors are all the same but they arnt using the full sensor? Like say the SD600-SD900 all use the same sensor but the 600 is crippled or limited using software and as they progress up in model the sensor is "unlocked" each step till it reaches its max pixel/noise limit?

Would the SD600 actualy take better pictures at a similar resolution because there are less pixals around it causing noise?

[gmtech79]

I can't exactly answer your question specifically, but it did seem that when I went from my olympus c-4000 which was a 4 megapixel camera to the canon S3 which as you know is a 6 megapixel camera, I noticed a huge jump in noise. Now with my D80 I notice way less noise than both of them but of course a D80 is slr and has a much larger sensor so it really isn't comparing apples to apples.


Do the sensor's from each camera that you mention have the same part number from canon? Because at first thought I would say that as technology evolves they are able to get more pixels (actually photovoltaic cells, I believe) onto the sensor.

[BowerR64]

I dont know if they are the same part number.

What makes me curious is the CCD recall if you look at the list of cameras affected by this problem they all use the same sensor yet they are all of various mega pixel ratings. They go from 2-5 mega pixel and even other manufactures used this same CCD that are on the list of cameras affected.

It just seems odd that if they were the same size but more mega pixels crammed in there they would have the same defect as one that is a lower rated sensor. Its like they all go threw the same process and that seems strange to me.

Another thing is many have the same sensor yet some have higher ISO ratings how can they do that? pulling more megapixels and higher ISO from the same sensor? i dont get it.

[cdifoto]

What makes me curious is the CCD recall if you look at the list of cameras affected by this problem they all use the same sensor yet they are all of various mega pixel ratings. They go from 2-5 mega pixel and even other manufactures used this same CCD that are on the list of cameras affected.

That doesn't mean it's the same sensor. Unless Canon specifically states the sensors are the same one (which I doubt is even possible). It simply means the ones made using those manufacturing processes are affected.

As far as I know you cannot physically have a 7.1MP and 5MP made from the same sensor unless you start getting into fake megapixels via interpolation. Canon does not use interpolation. You CAN however have different megapixels in the same SIZE sensor. Example being the Canon 1Ds II having a 16.7MP full frame sensor and the Canon 5D having a 12MP full frame sensor. It's not the same sensor though. They only share the common trait of physical dimensions.

[mattdm]

What makes me curious is the CCD recall if you look at the list of cameras affected by this problem they all use the same sensor yet they are all of various mega pixel ratings. They go from 2-5 mega pixel and even other manufactures used this same CCD that are on the list of cameras affected.

If I recall, these weren't the exact same sensor, but rather from the same generation of chip manufacturing technology at Sony's sensor factories.



It just seems odd that if they were the same size but more mega pixels crammed in there they would have the same defect as one that is a lower rated sensor. Its like they all go threw the same process and that seems strange to me.


Why does that seem odd? Consider that the 2 gigabyte compact flash card I have is the same size as the 16 megabyte one I had several years ago. Technology improves -- they pack more photoreceptor sites into the same area, just as they pack more flash memory cells into the same area.

Another thing is many have the same sensor yet some have higher ISO ratings how can they do that? pulling more megapixels and higher ISO from the same sensor? i dont get it.

Again, better technology. More sensitive photoreceptors. This really shouldn't be too shocking even if you're coming from an "analog" photography background. Original Kodachrome film had an ISO rating of 6.

[gmtech79]

As far as I know you cannot physically have a 7.1MP and 5MP made from the same sensor unless you start getting into fake megapixels via interpolation. Canon does not use interpolation. You CAN however have different megapixels in the same SIZE sensor. Example being the Canon 1Ds II having a 16.7MP full frame sensor and the Canon 5D having a 12MP full frame sensor. It's not the same sensor though. They only share the common trait of physical dimensions.

Could you elaborate on what you mean that canon doesn't use interpolation, because as far as any info I have found is that all sensor's regardless of manufacturer, use bayer interpolation except for foveon sensor's?

[cdifoto]

Could you elaborate on what you mean that canon doesn't use interpolation, because as far as any info I have found is that all sensor's regardless of manufacturer, use bayer interpolation except for foveon sensor's?

Sorry I should have been more specific. I was thinking of the bad kind of interpolation...digital cropping if you wanna call it that. Taking a 3MP sensor and interpolating it to 12MP like those generic eBay wondercams that really suck.

[gmtech79]

Oh, ok. I was just curious what you meant exactly. Thanks for clearing that up.

[BowerR64]

So they ARE using interpolation but its not just a generic type its bayer interpolation. Thanks for the info

[mattdm]

So they ARE using interpolation but its not just a generic type its bayer interpolation. Thanks for the info

Err, yeah, but it's not a matter of "generic" vs. brand name. None of the (quality manufacturer) cameras use interpolation to increase the number of megapixels. All of them, however, including the low-res ones, use Bayer interpolation to determine color. That's really a different issue.

[Razr]

Panasonic FZ20 & FZ30.

FZ20: the FZ20 is f/2.8 throughout the zoom range (36-432mm) @ 5.1 Megapixels for the FZ20;
f/2.8-f/.37 (35-420mm), 8 Megapixels for the FZ30, partly because the sensor size on the FZ30 is slightly larger (but because the same lens is used, the FZ30 is a little slower).

Sensor size, same lens combination on the FZ20 lets it remain the only (f/2.8 constant aperture) "superzoom" ever made.

In this instance, a smaller sensor makes for faster aperture with the same lens.
Even with a OLYMPUS T-CON 1.7 mounted, the FZ20 is still only F/3.5 at the 735mm-12X end, the slower lens speed due in part to the light loss in the T-CON.