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Author Topic: Digital Camera Database looking for feedback  (Read 5646 times)
gregorb
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« on: October 04, 2012, 01:36:28 PM »
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Hi,

my name is Gregor and I'm the creator of Digital Camera Database (www.digicamdb.com). This is a brand new site that is focused primarily on sensor info and provides often hard to find information (sensor dimensions, pixel pitch, pixel density, etc.) for more than 3200 digital cameras. It also allows you to visually compare actual sensor sizes and other sensor characteristics.

I would greatly appreciate if you would give it a test drive and perhaps provide some feedback, especially if you spot any errors. I hope you will find it useful.

I also have a special question for fellow Americans. I'm from Slovenia and the site is currently all metric, I would, however, like to provide imperial measurements in cases where it makes sense. It would be great, if you could enlighten me on this subject and tell me what numbers would you like to see in inches, if any? Do micro inches make sense?

Thank you all for your time and special thanks to Mr. Sanderson for being kind enough to let me post this.

Kind regards,
Gregor Brdnik
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lfeagan
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« Reply #1 on: October 04, 2012, 02:22:33 PM »
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Hi Gregor,

Your website is nicely put together and easy to use.

Regarding units, I am comfortable with exclusively metric units for the sensor section. The two places where British units make sense to me are:
  • Camera weight, in pounds + ounces notation (for example: 2 lb 3 oz)
  • Body dimensions, in inches (for example: 2.4" x 4.7" x 1.4")

The LCD size already uses inches, and I liked that. I noticed that the Canon 5D Mark III was missing the units double-quote mark for the LCD size and just says 3.2 instead of saying 3.2". For comparison, the Nikon D800e does have the double-quote to indicate inches.
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Nikon: D700, D800E, PC-E 24mm f/3.5D ED, PC-E 45mm f/2.8D ED, PC-E 85mm f/2.8D, 50mm f/1.4G, 14-24 f/2.8G ED, 24-70 f/2.8G ED, 70-200 f/2.8G ED VR II, 400mm f/2.8G ED VR
Fuji: X-Pro 1, 14mm f/2.8, 18mm f/2.0, 35mm f/1.4
marcmccalmont
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« Reply #2 on: October 06, 2012, 10:58:06 AM »
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It would be nice if DxO and DPreview ratings were included.
Marc
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Marc McCalmont
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« Reply #3 on: October 06, 2012, 06:01:22 PM »
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Hi,

my name is Gregor and I'm the creator of Digital Camera Database (www.digicamdb.com). This is a brand new site that is focused primarily on sensor info and provides often hard to find information (sensor dimensions, pixel pitch, pixel density, etc.) for more than 3200 digital cameras. It also allows you to visually compare actual sensor sizes and other sensor characteristics.

Hi Gregor,

Thanks for that initiative, it can be quite useful if the data can be depended upon. It must have been a lot of work collecting all that data from various sources, you've made a good start.

Quote
I would greatly appreciate if you would give it a test drive and perhaps provide some feedback, especially if you spot any errors. I hope you will find it useful.

Okay, here's a critical note (intended as an encouragement and for improvement of the usefulness).

I'll use one of my cameras (a Canon EOS 1DS Mark III) as a specific example. I have not tested the database for other cameras, but I'll assume similar results when the same method was used.

One of the many parameters that interests me (because it is the basis of many other relevant calculations), is the sensel pitch. You use an indirect method of calculating it from the total Megapixel amount (which is a rounded number anyway)  that in this particular (1Ds3) case results in an approx. 2% error in the sensel pitch from what we are told be several other sources. It may not seem like much, but it is significant enough for some uses to get me to write this (and who knows how much it deviates for other cameras).

To be more specific, here are some other sources of information:
Code:
DCRaw: 5640 x 3752 px (incl. cropped/rounded to multiples of 16 edge pixels)
RawDigger: 5640 x 3752 px (incl. cropped/rounded edge pixels)
RawDigger: 5712 x 3774 px (incl. non-imaging technical sensels)
DigiCamDB: 5732 x 3821 px (due to reverse engineered quantities from "Total megapixels = 21.90")

DigiCamDB: 6.28 m
EXIFtool FocalplaneXresolution: 6.4178 m (3957.716702 PPI)
EXIFtool FocalplaneYresolution: 6.4111 m (3961.904762 PPI)

Due to the indirect calculation, you arrive at an overstated number of sensels, which in turn leads to an understated sensel pitch in this case. It's a 2% difference for the sensel pitch, which is unfortunately too much of a difference to allow to use it for other calculations.

Cheers,
Bart
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gregorb
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« Reply #4 on: October 07, 2012, 04:45:49 AM »
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Thank you all for commenting and thank you Bart for taking the time to write a very informative post. I appreciate it.

I understand the problem, I do, however, depend on the data provided by the manufacturers, which is not 100% accurate. Total megapixels which are used to calculate sensor resolution are in most cases rounded up. How much, I can't really know. But in order to calculate everything for 3200+ digital cameras, I have to use indirect calculations with this data.

At this point, I don't see a better way of doing it.


About your example (Canon EOS 1DS Mark III), here are my observations:

It makes sense to me to calculate pixel pitch from total number of pixels. So, if I were to use sensor resolution from RawDigger that you provided - 5712 x 3774 px (incl. non-imaging technical sensels), I would get:

Pixel pitch horizontal: 6.3 (0.3% difference from digicamdb)
Pixel pitch vertical: 6.35 (1.1% difference)

If I were to use effective megapixels or just max. image resolution (5616 x 3744), I would get 6.41. But this doesn't make sense to me, because not all pixels are used in the calculation, resulting in a higher pitch.

Most people calculate pixel pitch with max image resolution (effective pixels), so the results are slightly higher than what my site shows.

Now, I could just change the formula on my site to calculate it like that and it would then show the "correct" value, but my common sense tells me that that is not the way to do it.

Gregor
« Last Edit: October 07, 2012, 06:27:19 AM by gregorb » Logged
BartvanderWolf
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« Reply #5 on: October 07, 2012, 06:33:50 AM »
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But in order to calculate everything for 3200+ digital cameras, I have to use indirect calculations with this data.

At this point, I don't see a better way of doing it.

Hi Gregor,

I understand the issue, it would not be feasible to analyse the EXIF data of all cameras, due to time constraints.

Quote
About you example (Canon EOS 1DS Mark III), here are my observations:

It makes sense to me to calculate pixel pitch from total number of pixels. So, if I were to use sensor resolution from RawDigger that you provided - 5712 x 3774 px (incl. non-imaging technical sensels), I would get:

Pixel pitch horizontal: 6.3 (0.3% difference from digicamdb)
Pixel pitch vertical: 6.35 (1.1% difference)

If I were to use effective megapixels or just max. image resolution (5616 x 3744), I would get 6.41. But this doesn't make sense to me, because not all pixels are used in the calculation, resulting in a higher pitch.

To me it would make more sense, because it is closer to what the 'FocalplaneXresolution' and 'FocalplaneYresolution' datafields in the EXIF tell us. And who knows better than the manufacturer?

Cheers,
Bart
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gregorb
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« Reply #6 on: October 07, 2012, 07:38:33 AM »
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To me it would make more sense, because it is closer to what the 'FocalplaneXresolution' and 'FocalplaneYresolution' datafields in the EXIF tell us. And who knows better than the manufacturer?

As far as I understand, the EXIF data describes the image resolution (effective MP), not the sensor resolution (total MP). Here is a definition taken from EXIF 2.2 specifications:

FocalPlaneXResolution
Indicates the number of pixels in the image width (X) direction per FocalPlaneResolutionUnit on the camera focal plane.

FocalPlaneYResolution
Indicates the number of pixels in the image height (Y) direction per FocalPlaneResolutionUnit on the camera focal plane.

Note on use of tags concerning focal plane resolution
These tags record the actual focal plane resolutions of the main image which is written as a file after processing instead of the pixel resolution of the image sensor in the camera. It should be noted carefully that the data from the image sensor is resampled.


Gregor
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BartvanderWolf
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« Reply #7 on: October 07, 2012, 04:19:21 PM »
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As far as I understand, the EXIF data describes the image resolution (effective MP), not the sensor resolution (total MP). Here is a definition taken from EXIF 2.2 specifications:

FocalPlaneXResolution
Indicates the number of pixels in the image width (X) direction per FocalPlaneResolutionUnit on the camera focal plane.

FocalPlaneYResolution
Indicates the number of pixels in the image height (Y) direction per FocalPlaneResolutionUnit on the camera focal plane.

Note on use of tags concerning focal plane resolution
These tags record the actual focal plane resolutions of the main image which is written as a file after processing instead of the pixel resolution of the image sensor in the camera. It should be noted carefully that the data from the image sensor is resampled.


Hi Gregor,

The text continues with:
"These tags are used at the same time as a FocalLength tag when the angle of field of the recorded image is to
be calculated precisely."

The EXIF data describes the sampling density (default is per inch) in the focus plane, expressed as pixels after demosaicing. The units are usually reported as fixed point numbers and report the number of samples/pixels per inch in the focus plane. It is not calculated from other values (which would be redundant), but specified.

The "Note on use of tags concerning focal plane resolution" specifies that e.g. not the resolution of the green sensitive sensels is counted (which would be half the resolution), but the resolution after demosaicing, RGB pixels (full RGB resolution) per unit length (usually per inch). That also allows to specify the correct resolution for sensors with non-square RGB pixels, or binned pixels, and calculate angles of view.

This can also be verified by shooting an object of know dimensions, at an exactly known distance. That will allow to calculate the sensel pitch by counting pixels. It's more accurate at larger distances because the focal length of a lens is usually specified at infinity focus.

It can e.g. be used to predict how many pixels the diameter of a full moon will be on the sensor array. On October 29th, 2012 the moon with a average diameter of 3475 km will be at a distance of 401427 km, and has an angular diameter of 0.49598 degrees seen from earth, or 0.8618 mm for each 100 mm of focal length, so 134.45 pixels @ 6.41 micron. This is just one of the applications of accurate sensel pitch numbers, it becomes more serious if photogrammetric, medical, or forensic work is done.

Cheers,
Bart
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gregorb
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« Reply #8 on: October 08, 2012, 09:01:28 AM »
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Thank you Bart for a very insightful answer. I'm certainly not an expert (like most of you here), I'm just an IT guy with an interest in digital cameras, who wants to do things right.

I did some additional reading on the subject and it appears that you are correct the EXIF data seems to be the most accurate way to get the pixel pitch.

I searched for EXIF data for about 15 different cameras and then compared my calculations with the pixel pitch I got from EXIF data. I found that if I use the most simplest formula (sensor width/max. image resolution width) I get the most accurate results. In most cases it's between 0 0.3% difference compared to EXIF pixel pitch.

I will probably do a compromise. I will use EXIF data for DSLRs and for the rest sensor width/max. image resolution formula. This way at least high end cameras will have the most accurate numbers possible.


The whole thing, however, still seems a bit illogical to me. I try to imagine pixels on a sensor in a physical way. You have a sensor of a certain size and a certain (total) number of pixels on it. If you want to know horizontal pixel pitch, you take the full width of the sensor and simply divide it with all the horizontal pixels. Simple and logical.

But if you use max image resolution width, you only use like 95% of the pixels that are on the sensor. You use full sensor width, but only 95% of the pixels and you get more accurate pixel pitch (according to EXIF) than if using all pixels (sensor resolution). I still can't get my head around this.

Gregor
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BartvanderWolf
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« Reply #9 on: October 08, 2012, 10:14:32 AM »
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Thank you Bart for a very insightful answer. I'm certainly not an expert (like most of you here), I'm just an IT guy with an interest in digital cameras, who wants to do things right.

I did some additional reading on the subject and it appears that you are correct the EXIF data seems to be the most accurate way to get the pixel pitch.

I searched for EXIF data for about 15 different cameras and then compared my calculations with the pixel pitch I got from EXIF data. I found that if I use the most simplest formula (sensor width/max. image resolution width) I get the most accurate results. In most cases it's between 0 0.3% difference compared to EXIF pixel pitch.

I will probably do a compromise. I will use EXIF data for DSLRs and for the rest sensor width/max. image resolution formula. This way at least high end cameras will have the most accurate numbers possible.

Hi Gregor,

Given the huge task, you indeed want to use something that can preferably be automated. DSLRs can be used by various types of users, so it makes sense to get those numbers as accurate as humanly possible.

Quote
The whole thing, however, still seems a bit illogical to me. I try to imagine pixels on a sensor in a physical way. You have a sensor of a certain size and a certain (total) number of pixels on it. If you want to know horizontal pixel pitch, you take the full width of the sensor and simply divide it with all the horizontal pixels. Simple and logical.

The problem is with the size specifications given by the manufacturers. They are not necessarily very accurate, but in the EXIF data the information is more accurate because it is used internally by the camera, and later for postprocessing (e.g. lens corrections). Therefore we should be able to rely on the EXIF data, although we need to understand what they exactly mean. As for the data tagged with FocalPlaneXResolution and FocalPlaneXResolution, it is the actual sensel density per linear (X/Y) dimension. How many of those sensels are fitted in the total image doesn't change their sampling density, it just determines the total dimensions of the effective sensor area.

Part of the sensor area (at one or more edges) holds technical sensels which do not contribute directly to the image formation, e.g. masked sensels to determine the noise/black level without exposure. Then there are edge sensels that are required for demosaicing, which can require a wider area around the principle pixel that is being demosaiced. And then there is a crop applied to get the demosaiced image pixel dimensions to a multiple of 16, for the generation of JPEGs and full size preview thumbnails. The question then becomes, when a manufacturer says the sensor dimension is 36x24mm, which sensels are included in those dimensions? That's why it is so tricky to start with the total dimensions. It's much safer to start with the EXIF FocalPlane Resolutions, and that info is available from all those sample files made available by sites such as Imaging Resource, DPreview, etc. .

See also this explanation and this.

Quote
But if you use max image resolution width, you only use like 95% of the pixels that are on the sensor. You use full sensor width, but only 95% of the pixels and you get more accurate pixel pitch (according to EXIF) than if using all pixels (sensor resolution). I still can't get my head around this.

It's the difference between effective pixels, total pixels, and border sensels. Not all input sensor elements are counted for the published output MegaPixel specifications. The EXIF 'Maker notes' for my 1Ds3 specifies the different sensel/pixel dimensions in the metadata fields;
CroppedImageWidth:  5616 (as output to a JPEG, cropped to a 3:2 aspect ratio and a multiple of 16 pixels, and corresponds to 36mm)
CroppedImageHeight: 3744 (as output to a JPEG, cropped to a 3:2 aspect ratio and a multiple of 16 pixels, and corresponds to 24mm)
SensorWidth: 5712  (as used to demosaic, and output by some Rawconverters)
SensorHeight: 3774 (as used to demosaic, and output by some Rawconverters)
And then there are additional border pixels specified, but I'm not sure that the Tag meaning has been reverse engineered correctly.

Cheers,
Bart
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gregorb
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« Reply #10 on: October 08, 2012, 11:02:15 AM »
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Bart, you're the man! I want to thank you for taking the time to write all of your helpful posts. Your knowledge is truly impressive. I really appreciate it.

Thanks,
Gregor
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BartvanderWolf
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« Reply #11 on: October 08, 2012, 05:09:11 PM »
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Bart, you're the man! I want to thank you for taking the time to write all of your helpful posts. Your knowledge is truly impressive. I really appreciate it.

Hi Gregor,

You're welcome, I'm just trying to help.

Cheers,
Bart
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Canon Bob
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« Reply #12 on: October 10, 2012, 10:42:00 PM »
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A useful resource, Gregor, thanks for taking the time to put it together.

Bob


My first test run came up with an entry that is factually incorrect (I suspect it was picked from another site with the error). The battery information for the Eos IDs MkIII shows a BP511a whereas it should be an LC-E4.
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gregorb
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« Reply #13 on: October 11, 2012, 09:05:48 AM »
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I did some research, looked at how others calculate pixel pitch and here are my findings.

DxO uses EXIF sensor resolution to calculate pixel pitch. Most other people, most review sites use just max. image resolution.

I can't use FocalPlane(X/Y)Resolution for two reasons:

1. It's available only for Canon and Fujifilm cameras.
2. Sometimes it gives weird results (like EOS 1D X see below).

There is so much conflicting information out there that the more I delve into this, the more I'm convinced that the search for accurate pixel pitch is futile. I'm going to give you three examples, so that you can see what I mean:

Canon EOS 5d Mark III

Sensor size: 36 x 24 mm
Max image resolution:        5760 x 3840
EXIF sensor resolution:      5920 x 3950
DigiCamDB sensor resolution: 5925 x 3950
FocalPlaneXresolution: 3942.505133
FocalPlaneYresolution: 3950.617284

DxO:                               6.08 (36/5920)
DigiCamDB:                         6.08 (36/5925)
EXIF (from FocalPlaneXresolution): 6.44
Sensor_width/max_image_res:        6.25 (36/5760)
Canon specifications:              6.25 (36/5760)

Multiplying EXIF pixel pitch with EXIF sensor resolution: 6.44 x 5920 = 38.12 mm


Canon EOS 1Ds Mark III

Sensor size: 36 x 24 mm
Max image resolution:        5616 x 3744
EXIF sensor resolution:      5712 x 3774
DigiCamDB sensor resolution: 5732 x 3821
FocalPlaneXresolution: 3957.716702
FocalPlaneYresolution: 3961.904762

DxO:                               6.3 (36/5712)
DigiCamDB:                         6.28 (36/5732)
EXIF (from FocalPlaneXresolution): 6.42
Sensor_width/max_image_res:        6.41 (36/5616)

Multiplying EXIF pixel pitch with EXIF sensor resolution: 6.42 x 5712 = 36.67 mm


Canon EOS 1D X

Sensor size: 36 x 24 mm
Max image resolution:        5184 x 3456
EXIF sensor resolution:      5344 x 3584
DigiCamDB sensor resolution: 5381 x 3587
FocalPlaneXresolution: 5728.176796
FocalPlaneYresolution: 5702.970297

DxO:                               6.74 (36/5344)
DigiCamDB:                         6.69 (36/5381)
EXIF (from FocalPlaneXresolution): 4.43
Sensor_width/max_image_res:        6.94 (36/5184)

Multiplying EXIF pixel pitch with EXIF sensor resolution: 4.43 x 5344 = 23.67 mm



As you can see, things aren't pretty. So what to do, that is the question?

Perhaps the most appropriate route would be to use the standard formula (sensor width / max. image resolution width) simply because it appears to be a convention. It's certainly not accurate, but most people use it, most review sites use it, and even the manufacturers sometimes use it (as we can see from 5d Mark III example).

Or I could figure out a way to apply a correction to my sensor resolution calculation to be as close as possible to EXIF sensor resolution. My results would then be very much similar to those at DxO, only for 3200+ cameras.

I'm leaning towards the latter option.

Gregor

@Canon Bob: Thanks, it's been corrected.
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BartvanderWolf
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« Reply #14 on: October 12, 2012, 05:38:22 AM »
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As you can see, things aren't pretty. So what to do, that is the question?

Perhaps the most appropriate route would be to use the standard formula (sensor width / max. image resolution width) simply because it appears to be a convention. It's certainly not accurate, but most people use it, most review sites use it, and even the manufacturers sometimes use it (as we can see from 5d Mark III example).

Hi Gregor,

The 1D X FocalPlaneXresolution looks very strange indeed, and the DxO Mark database doesn't have a sensel pitch recorded for that camera. Adding that that metric isn't available for most other camera brands, would make it not the best thing to use for your database.

I haven't checked for all other camera brands/models, but it would seem that "sensor width / max. image resolution width" comes overall closest to what one can assume to be realistic across the board.

Cheers,
Bart
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« Reply #15 on: December 15, 2012, 12:37:31 PM »
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Hello Gregor,

A monumental task and really good web design - I am very impressed.

I can understand that it is easier to calculate sensor pixels size and pitch from a published MP figure but it does lead to inaccuracies which came as a bit of a surprise when I compared my two cameras, Sigma SD10 and Nikon D50.

I'll use [square brackets] below to show correct figures:
Sensor type
   Foveon X3    CCD
Sensor size
   20.7 x 13.8 mm    23.7 x 15.6 mm
Sensor resolution
   2259 x 1506 [2268x1512]     3045 x 2003 [3008x2000]
 Pixel pitch
   9.16 m [9.12]     7.78 m  [7.88]

The above is just a comment - you don't to make any corrections for me!

For the Foveon sensor you say:

"Traditional CCD/CMOS sensors have 1 pixel for 1 color, whereas Foveon sensor captures all 3 colors (blue, green, and red) at every pixel. In theory this means that Foveon sensor has the potential for 3 times the resolution of a traditional sensor of the same size.
Sensor"

I do feel that this statement should be corrected for the Sigma cameras. Firstly, tradition sensors (as you know) have 1 red, 2 green and 1 blue pixels in groups of four - making "1 pixel for 1 color" slightly misleading for beginners. Secondly, "the potential for three times the resolution" is incorrect. The spatial resolution of a Foveon sensor is just the pixel pitch, no more that that. However, there is considerably discussion about the "equivalent MP" (horrible phrase) of a Foveon vs. a Bayer array camera and, from that viewpoint of image quality, it is generally accepted that a Foveon-based camera is equivalent to a Bayer camera that has about 50% more pixels.

Best Regards,

Ted
   
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best regards,

Ted
gregorb
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« Reply #16 on: December 16, 2012, 03:12:48 AM »
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Thanks for your comment Ted.

I have to tell you though that your method of calculating pixel pitch (sensor width/max. image resolution width) isn't really [correct]. I know most people are using that formula, but that doesn't mean it's accurate.

I was able to get a hold of SEM (scanning electron microscope) measured pixel sizes for about 60 different cameras (DSLRs, compacts, old and new) and have compared different pixel pitch formulas to those numbers. The method I'm currently using gives me the most accurate results (average difference 0.7% compared to SEM measured pixel pitch, 1.7% if using your method).

I don't want to bore you with the details, but overall statistically (across all 3300+ cameras), the method I'm using is the most accurate you can get with data from camera spec sheets and without looking through a microscope.

Of course this isn't exact science, simply because data available from manufacturers is not exact, but it's pretty close.

About Foveon sensors: That text was rather hastily put together and yes - it needs revision. Thanks for reminding me.

Regards,
Gregor
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« Reply #17 on: December 16, 2012, 11:16:05 AM »
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Thank you Gregor,

You said "I have to tell you though that your method of calculating pixel pitch (sensor width/max. image resolution width) isn't really [correct]. I know most people are using that formula, but that doesn't mean it's accurate." I didn't understand that comment. I used no formula and did not use a method of calculation. The figures I quoted are from the Foveon sensor data sheet and from the Nikon D50 manual. What is the formula that you mentioned most people are using?

I did not see that you had made direct measurements of sensor sizes. A lot of work, most impressive! The instrument must be very accurate!

One difficulty I did have was with the width and height of pixel data, which surely can not be different from the data sheet. For example, the Foveon F7 sensor data sheet for the SD10 sensor model F7X3-C9110 clearly states:

Specifications
2268 columns x 1512 rows x 3 layers
Pixel Pitch 9.12 μm Center-to-center spacing of pixel locations
20.7 mm x 13.8 mm Active area
Aspect Ratio 3:2

I can understand that Foveon might round the sensor dimensions to one decimal place but I would have thought that the number of pixels on the sensor is a property of the photo-lithographic mask used to make the sensor chip and is certainly not variable. On the other hand, I agree that the pixel pitch could vary slightly and your value of 9.16um versus the Foveon data sheet's nominal 9.12um could be within the manufacturer's production tolerance which of course is not known to the public.

Best Regards,

Ted
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best regards,

Ted
gregorb
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« Reply #18 on: December 16, 2012, 02:07:12 PM »
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Hi Ted,

The usual way people are calculating pixel pitch is by dividing sensor width with max. image resolution width. If  I do that I get the numbers you provided (20.7/2268 = 9.127 microns) so I assumed you used that formula. Sorry for my faulty assumption.

Manufacturers also very rarely state pixel pitch and I have seen a few times they too just use this formula. SEM measured pixel pitch, which I trust to be accurate, may be slightly different (sadly I don't have it for SD10 or D50).

The problem with calculating pixel pitch from spec sheets is always inaccurate data. Sensor sizes are rounded (they are in mm not microns) and there are additional pixels on sensors required for stuff like demosaicing, so it's practically impossible to be 100% accurate without a microscope.

As I said, my tests and comparisons to SEM measured pixel sizes (which I got from a company that does sensor analysis) showed that statistically I get most accurate results using the method I use which is reverse engineering sensor resolution from effective MP.

Accuracy in individual cases may vary depending on the accuracy of the input data and you are probably correct about SD10, but I have to look at things overall (I use one formula for 3300+ cameras). As said, what I'm doing is not exact science, but usually very close.

Regards,
Gregor
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xpatUSA
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« Reply #19 on: December 16, 2012, 02:55:51 PM »
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Thanks Gregor,

I now understand your point of view which does make good sense. I can see that the design parameters for a sensor photo-mask is going to be required number of pixels,overall mask size (which relates to how many chips will be made from one silicon slice) and the lithographic technology used e.g. 0.18um. From that point of view, the pixel pitch would indeed result from those parameters, rather than setting them. And of course the pixel dimensions including metallization, transistors and active (doped) area would have to fit within the bounds of the pixel pitch "lines".

So, in other words, the designers start with an MP requirement, a sensor size and a given technology and the pixel pitch is whatever it turns out to be!

Interesting discussion - thanks!
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best regards,

Ted
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