GH2 Variable Aspect Ratio

Started Apr 23, 2012 | Discussions
Detail Man
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Re: GH2 Variable Aspect Ratio - Mpixel Sizes
In reply to Adventsam, Apr 23, 2012

Adventsam wrote:

Detail Man wrote:

Louis_Dobson wrote:

Is the 16:9 still roughly 16MP?

4:3 = 15.925428 Mpixels

3:2 = 15.054336 Mpixels

4:3 = 13.932800 Mpixels

You mean, 14Mp? also for note the OMD is only 12Mp in 16:9 ratio, thats a bad for me.

Multiply the number of vertical and horizontal pixels listed in your GH2 Operating Instructions.
It is 13.932800 Mpixels.

OMD 16:9 ratio is 12Mp, GH2 is 14Mp!!! 3:2 is 15Mp, which should tell you alot more because essentially the 3:2 ratio of the GH2 is very similar in FOV and DR to the Sony 16Mp 3:2 ratio, despite what all the headlines say.

Sam, how much money do you pay Panasonic to say all those nice things about the GH2 ?? ...

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Detail Man
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Re: DM, your pixel pitch for GH2 is wrong!
In reply to Adventsam, Apr 23, 2012

Adventsam wrote:

How do you get such a pixel pitch, its the same as the other 16mp sensors, you just have a much larger sensor.

I am afraid that you need to accuse DxOMark of being wrong, Sam.
Read my post (quoted below) that you responded to ...

See: http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Panasonic/Lumix-DMC-GH2

Detail Man wrote:

kenw wrote:

Technically the crop ratio is defined by the ratio of the diagonal. When we say m43 is a 2x crop factor this is the ratio of the diagonal of the 3:2 aspect full frame 35mm sensor to the diagonal of the 4:3 aspect m43 sensor.

For the GH2 the diagonals of all the different aspect ratios are the same so the crop factor is always the same: 2x. For the other m43 cameras the non-4:3 aspects actually all have a crop factor greater than 2x.

That's what the standard definition of crop factor is.

Now you are asking specifically about the horizontal field of view rather than the diagonal. If you want you could calculate horizontal "crop factors" instead.

Using DxOMark's specification of 3.63 Microns pixel-pitch (height and width) for the GH2's image-sensor's photo-sites, and the 36.000 mm width dimension of 35mm full-frame, here are the (horizontally referenced) Crop Factors to mutlipy your lens-system Focal Length by:

4:3 - Crop Factor = 1.721763

3:2 - Crop Factor = 1.736477

16:9 - Crop Factor = 1.736934

The 16:9 aspect-ratio mode is (again) the "widest" of them all (by a miniscule amount, anyway), having the largest Crop Factor.

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Mike Ronesia
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Re: DM, your pixel pitch for GH2 is wrong!
In reply to Detail Man, Apr 23, 2012

So if the GH2 has a 114 degree FOV at 4/3's with the 7-14 at 7, what is the FOV at 16/9 at 7? It must be closer to 120 degrees or more. All I know is it is darn wide and maybe the widest non-fish eye on the market for any system.
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Jimbo70
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Re: GH2 Variable Aspect Ratio
In reply to Adventsam, Apr 23, 2012

Adventsam wrote:

28 @4:3 ie 2.0x, 1.8x horizontal fov @16:9 and 1.9x @3:2

Looking at this diagram you can see the 16-9 ratio is wider than the 4-3 ratio. So if the 14mm (28mm equiv) is 14mm with the 4-3 ratio it must be wider with the 16-9 ratio. Conversely if the 14mm is 14mm with the 16-9 ratio it must be less with the 4-3 ratio. Sorry if i wasn't clear before. Jim

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Detail Man
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FOV for GH2 in 16:9 Aspect Ratio Mode with 7mm Focal Length Lens
In reply to Mike Ronesia, Apr 23, 2012

Mike Ronesia wrote:

So if the GH2 has a 114 degree FOV at 4/3's with the 7-14 at 7, what is the FOV at 16/9 at 7? It must be closer to 120 degrees or more. All I know is it is darn wide and maybe the widest non-fish eye on the market for any system.

Diagonal Field of View :

FOV = (2) x ( Arctangent ( ( 10.36309 ) / (Focal Length in mm) ) ) = 111.924 Degrees

Horizontal Field of View :

FOV = (2) x ( Arctangent ( ( 9.03144 ) / (Focal Length in mm) ) ) = 104.443 Degrees

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Steen Bay
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Re: GH2 Variable Aspect Ratio
In reply to Jimbo70, Apr 23, 2012

Jimbo70 wrote:

Adventsam wrote:

28 @4:3 ie 2.0x, 1.8x horizontal fov @16:9 and 1.9x @3:2

Looking at this diagram you can see the 16-9 ratio is wider than the 4-3 ratio. So if the 14mm (28mm equiv) is 14mm with the 4-3 ratio it must be wider with the 16-9 ratio. Conversely if the 14mm is 14mm with the 16-9 ratio it must be less with the 4-3 ratio. Sorry if i wasn't clear before. Jim

What matters when talking FoV/AoV is the diagonal, and the diagonal is the same for all the aspect ratios, so 14mm is 14mm, both when shooting 4:3 and when shooting 16:9.

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Detail Man
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Re: GH2 Variable Aspect Ratio
In reply to Steen Bay, Apr 23, 2012

Steen Bay wrote:

Jimbo70 wrote:

Adventsam wrote:

28 @4:3 ie 2.0x, 1.8x horizontal fov @16:9 and 1.9x @3:2

Looking at this diagram you can see the 16-9 ratio is wider than the 4-3 ratio. So if the 14mm (28mm equiv) is 14mm with the 4-3 ratio it must be wider with the 16-9 ratio. Conversely if the 14mm is 14mm with the 16-9 ratio it must be less with the 4-3 ratio. Sorry if i wasn't clear before. Jim

DxOMark specifies GH2 pixel-pitch at 3.63 Microns (not 3.8 Microns indicated in graphic posted).

What matters when talking FoV/AoV is the diagonal, ...

or the horizontal, or the vertical.

... and the diagonal is the same for all the aspect ratios, ...

Close, but not precisely the same.

... so 14mm is 14mm, both when shooting 4:3 and when shooting 16:9.

Diagonal Crop Factors:

4:3 - Crop Factor = 2.069320
3:2 - Crop Factor = 2.087004
16:9 - Crop Factor = 2.087553

Horizontal Crop Factors:

4:3 - Crop Factor = 1.721763
3:2 - Crop Factor = 1.736477
16:9 - Crop Factor = 1.736934

So 14mm is not 14mm. It is 14mm multiplied by the Crop Factors listed above.

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Condor
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"Multple Aspect Ratios"
In reply to Steen Bay, Apr 23, 2012

By the way,

This fantastic GH2 feature, which is a very important benefit for all of us who just take 16:9 photos, is indeed called "Multiple Aspect Ratios" by Panasonic, as in this useful animation mentioned in this E-M5 vs GH2 comparative 16:9 test request.

http://forums.dpreview.com/forums/read.asp?forum=1041&message=41301808

Ed

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Steen Bay
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Re: GH2 Variable Aspect Ratio
In reply to Detail Man, Apr 23, 2012

Detail Man wrote:

Steen Bay wrote:

DxOMark specifies GH2 pixel-pitch at 3.63 Microns (not 3.8 Microns indicated in graphic posted).

If assuming that the active sensor area is app. 17.3x13mm when shooting a 4608x3456 4:3 image, then the pixel pitch is app. 3.76 micron.

What matters when talking FoV/AoV is the diagonal, ...

or the horizontal, or the vertical.

... and the diagonal is the same for all the aspect ratios, ...

Close, but not precisely the same.

... so 14mm is 14mm, both when shooting 4:3 and when shooting 16:9.

Diagonal Crop Factors:

4:3 - Crop Factor = 2.069320
3:2 - Crop Factor = 2.087004
16:9 - Crop Factor = 2.087553

Horizontal Crop Factors:

4:3 - Crop Factor = 1.721763
3:2 - Crop Factor = 1.736477
16:9 - Crop Factor = 1.736934

???

So 14mm is not 14mm. It is 14mm multiplied by the Crop Factors listed above.

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Detail Man
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Re: GH2 Variable Aspect Ratio
In reply to Steen Bay, Apr 23, 2012

Steen Bay wrote:

Detail Man wrote:

Steen Bay wrote:

DxOMark specifies GH2 pixel-pitch at 3.63 Microns (not 3.8 Microns indicated in graphic posted).

If assuming that the active sensor area is app. 17.3x13mm when shooting a 4608x3456 4:3 image, then the pixel pitch is app. 3.76 micron.

Tell it to DxOMark .. it looks like they do not agree with you .. maybe you will change their minds ?

See: http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Panasonic/Lumix-DMC-GH2

What matters when talking FoV/AoV is the diagonal, ...

or the horizontal, or the vertical.

... and the diagonal is the same for all the aspect ratios, ...

Close, but not precisely the same.

... so 14mm is 14mm, both when shooting 4:3 and when shooting 16:9.

Diagonal Crop Factors:

4:3 - Crop Factor = 2.069320
3:2 - Crop Factor = 2.087004
16:9 - Crop Factor = 2.087553

Horizontal Crop Factors:

4:3 - Crop Factor = 1.721763
3:2 - Crop Factor = 1.736477
16:9 - Crop Factor = 1.736934

???

!!!

So 14mm is not 14mm. It is 14mm multiplied by the Crop Factors listed above.

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Adventsam
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Re: DM, your pixel pitch for GH2 is wrong!
In reply to Mike Ronesia, Apr 23, 2012

Mike Ronesia wrote:

So if the GH2 has a 114 degree FOV at 4/3's with the 7-14 at 7, what is the FOV at 16/9 at 7? It must be closer to 120 degrees or more. All I know is it is darn wide and maybe the widest non-fish eye on the market for any system.
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It is Mike as AFAIK, 7mm @16:9 ratio is

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Steen Bay
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Re: GH2 Variable Aspect Ratio
In reply to Detail Man, Apr 23, 2012

Detail Man wrote:

Steen Bay wrote:

Detail Man wrote:

Steen Bay wrote:

DxOMark specifies GH2 pixel-pitch at 3.63 Microns (not 3.8 Microns indicated in graphic posted).

If assuming that the active sensor area is app. 17.3x13mm when shooting a 4608x3456 4:3 image, then the pixel pitch is app. 3.76 micron.

Tell it to DxOMark .. it looks like they do not agree with you .. maybe you will change their minds ?

See: http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Panasonic/Lumix-DMC-GH2

They use the correct 4:3 sensor size (17.3x13mm), but 4760x3472 pixels, that's not correct (it doesn't even match with the 4:3 aspect ratio).

What matters when talking FoV/AoV is the diagonal, ...

or the horizontal, or the vertical.

... and the diagonal is the same for all the aspect ratios, ...

Close, but not precisely the same.

... so 14mm is 14mm, both when shooting 4:3 and when shooting 16:9.

Diagonal Crop Factors:

4:3 - Crop Factor = 2.069320
3:2 - Crop Factor = 2.087004
16:9 - Crop Factor = 2.087553

Horizontal Crop Factors:

4:3 - Crop Factor = 1.721763
3:2 - Crop Factor = 1.736477
16:9 - Crop Factor = 1.736934

???

!!!

How can the horizontal crop factor, relative to FF, be different from app. 2.0x when shooting 3:2 images, with an active/effective GH2 sensor diagonal that's 0.5x the diagonal of a FF sensor?

So 14mm is not 14mm. It is 14mm multiplied by the Crop Factors listed above.

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mfj197
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Re: DM, your pixel pitch for GH2 is wrong!
In reply to Adventsam, Apr 23, 2012

Adventsam wrote:

Mike Ronesia wrote:

So if the GH2 has a 114 degree FOV at 4/3's with the 7-14 at 7, what is the FOV at 16/9 at 7? It must be closer to 120 degrees or more. All I know is it is darn wide and maybe the widest non-fish eye on the market for any system.
--
It's easier to ask for forgiveness then to ask for permission.

It is Mike as AFAIK, 7mm @16:9 ratio is

No, it's still 14mm. The 114 degree FOV is measured on the diagonal, and when changing ratios on the GH2 the diagonal FOV is (pretty much) the same. Sure, it covers a little more real estate horizontally but it's still 14mm. You could also increase your real estate across the horizon by simply tipping your camera to one side a bit - it's still 14mm.

Michael

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Adventsam
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Re: DM, your pixel pitch for GH2 is wrong!
In reply to mfj197, Apr 23, 2012

mfj197 wrote:

Adventsam wrote:

Mike Ronesia wrote:

So if the GH2 has a 114 degree FOV at 4/3's with the 7-14 at 7, what is the FOV at 16/9 at 7? It must be closer to 120 degrees or more. All I know is it is darn wide and maybe the widest non-fish eye on the market for any system.
--
It's easier to ask for forgiveness then to ask for permission.

It is Mike as AFAIK, 7mm @16:9 ratio is

No, it's still 14mm. The 114 degree FOV is measured on the diagonal, and when changing ratios on the GH2 the diagonal FOV is (pretty much) the same. Sure, it covers a little more real estate horizontally but it's still 14mm. You could also increase your real estate across the horizon by simply tipping your camera to one side a bit - it's still 14mm.

No its not, its much wider, your wrong, think about it dozy!

Michael

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Adventsam
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Re: GH2 is 3.8 pixel pitch
In reply to Steen Bay, Apr 23, 2012
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Detail Man
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Corrected: GH2 Image Sensor Diagonal and Horizontal Crop Factors
In reply to Steen Bay, Apr 23, 2012

Steen Bay wrote:

Detail Man wrote:

Steen Bay wrote:

Detail Man wrote:

Steen Bay wrote:

DxOMark specifies GH2 pixel-pitch at 3.63 Microns (not 3.8 Microns indicated in graphic posted).

If assuming that the active sensor area is app. 17.3x13mm when shooting a 4608x3456 4:3 image, then the pixel pitch is app. 3.76 micron.

Tell it to DxOMark .. it looks like they do not agree with you .. maybe you will change their minds ?

See: http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Panasonic/Lumix-DMC-GH2

They use the correct 4:3 sensor size (17.3x13mm), but 4760x3476 pixels, and that's not correct (it doesn't even match with the 4:3 aspect ratio).

Look in the meta-data of any GH2 image-file. 4760x3476 is the number of pixels that is reported. DxO Optics Pro allows access to and the use of (nearly, but I think not quite all of) them. I suppose that DxOMark probably has some expertise in measuring pixel-pitch, wouldn't you say ?

What matters when talking FoV/AoV is the diagonal, ...

or the horizontal, or the vertical.

... and the diagonal is the same for all the aspect ratios, ...

Close, but not precisely the same.

... so 14mm is 14mm, both when shooting 4:3 and when shooting 16:9.

Diagonal Crop Factors:

4:3 - Crop Factor = 2.069320
3:2 - Crop Factor = 2.087004
16:9 - Crop Factor = 2.087553

Horizontal Crop Factors:

4:3 - Crop Factor = 1.721763
3:2 - Crop Factor = 1.736477
16:9 - Crop Factor = 1.736934

How can the horizontal crop factor, relative to FF, be different from app. 2.0x when shooting 3:2 images, with an active/effective GH2 sensor diagonal that's 0.5x the diagonal of a FF sensor?

Diagonal Crop Factor for 3:2 Aspect Ratio :

Calculate the physical diagonal for 3.63 Micron pixel-pitch for Panasonic's 4752x3168 number of 3:2 Aspect Ratio mode pixels available (OOC JPGs), and you will get 20.732mm. Divide that diagonal dimension into the 43.267mm diagonal dimension of 35mm FF. That is what you get ...

Horizontal Crop Factor for 3:2 Aspect Ratio :

Steen : Thanks for alerting me that I had flubbed up the calculations. Here are the corrected (horizontal) Crops Factors below (for all Aspect Ratios). Think about it this way. The horizontal Field of View (has to be) less than the diagonal Field of View. Therefore, the Crop Factor has to be larger (because the Equivalent Focal Length has to be longer ). This makes intuitive sense ...

Calculate the physical horizontal for 3.63 Micron pixel-pitch for Panasonic's 4752 columns of 3:2 Aspect Ratio mode pixels available (OOC JPGs), and you will get 17.245mm. Divide that horizontal dimension into the 43.267mm (that's right) diagonal dimension of 35mm FF. That is what you get

All Diagonal Crop Factors :
4:3 - Crop Factor = 2.069320
3:2 - Crop Factor = 2.087004
16:9 - Crop Factor = 2.087553

So, none of them are exactly 28mm, all of them are a little bit "narrower" than 28mm (in terms of the Field of View), and the 4:3 aspect-ratio mode is the "widest" of them all (by a miniscule amount, anyway), having the smallest Crop Factor.

All Horizontal Crop Factors (corrected):
4:3 - Crop Factor = 2.586650
3:2 - Crop Factor = 2.508267
16:9 - Crop Factor = 2.395354

The 16:9 aspect-ratio mode is clearly the "widest" of them all, having the smallest Crop Factor.

So 14mm is not 14mm. It is 14mm multiplied by the Crop Factors listed above.

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dp88
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I specifically said I was talking about diagonal FOV
In reply to Adventsam, Apr 23, 2012

Diagonal FOV Is what matters for compression and expansion, but I'm repeating myself, since this is exactly what I said in my first post.

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mfj197
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Re: DM, your pixel pitch for GH2 is wrong!
In reply to Adventsam, Apr 23, 2012

Adventsam wrote:

mfj197 wrote:

Adventsam wrote:

Mike Ronesia wrote:

So if the GH2 has a 114 degree FOV at 4/3's with the 7-14 at 7, what is the FOV at 16/9 at 7? It must be closer to 120 degrees or more. All I know is it is darn wide and maybe the widest non-fish eye on the market for any system.
--
It's easier to ask for forgiveness then to ask for permission.

It is Mike as AFAIK, 7mm @16:9 ratio is

No, it's still 14mm. The 114 degree FOV is measured on the diagonal, and when changing ratios on the GH2 the diagonal FOV is (pretty much) the same. Sure, it covers a little more real estate horizontally but it's still 14mm. You could also increase your real estate across the horizon by simply tipping your camera to one side a bit - it's still 14mm.

No its not, its much wider, your wrong, think about it dozy!

Sam, the field of view is measured on the diagonal. Look at the diagram of the sensor you put up on this thread - that diagonal is described by the circle. The corners of all the various aspect ratios of the GH2 still touch this circle - they all have the same diagonal distance (23.68mm according to your diagram). Therefore they all have the same FOV.

Think about it this way. Put your GH2 in 4:3 mode, and tip the camera to the side until the two opposite corners of the image are lined up with the horizon and take a picture. Then put it into 16:9 mode, again tip the camera over until the two opposite corners are on the horizon, and take another picture. On both pictures the diagonal corners will be looking at the same points on the horizon, covering the same field of view.

Why do you think it is wider?

Michael

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Detail Man
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Re: I specifically said I was talking about diagonal FOV - Good Luck !
In reply to dp88, Apr 23, 2012

dp88 wrote:

Diagonal FOV Is what matters for compression and expansion, but I'm repeating myself, since this is exactly what I said in my first post.

But there is inevitably some character yabbering about how "wide" should - or must (really) - mean "horizontal", so I have learned to always calculate from that reference-point, too - for the "slobbering masses" who spell "math" as "maths", and think that rank ignorance is a virtue ! ...

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Detail Man
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Re: GH2 is 3.8 pixel pitch
In reply to Adventsam, Apr 23, 2012

Adventsam wrote:

Check this;
http://forums.dpreview.com/forums/read.asp?forum=1041&message=41305640

Funny thing, Sam. The eminent DPReview and the eminent Wikipedia both agree that 4/3 and Micro 4/3 image-sensors are (at most where it comes to active-area) 17.3mm x 13.0mm.

See these sources:
http://www.dpreview.com/learn/?/key=sensor%20sizes
http://en.wikipedia.org/wiki/File:SensorSizes.svg
http://en.wikipedia.org/wiki/Image_sensor_format#Common_image_sensor_formats

GH2 image-file meta-data states that the GH2 image-sensor (in 4:3 aspect-ration mode) has a grand total of 4760 x 3472 pixels (most of which DxO Optics Pro can use in RAW processing) ...

If one multiplies your claimed 3.8 Micron pixel-pitch by those numbers, one ends up with an active-area of 18.088mm x 13.1936mm. So, it rather sounds like incorrect bullcrap to me ...

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