GX8 20.3MP Sensor Question

Discussion in 'Panasonic Cameras' started by Hugo, Sep 16, 2015.

  1. Hugo

    Hugo Mu-43 Regular

    Sep 28, 2011
    Hi 4/3 experts,

    I have a basic question regarding the new GX8 sensor. All models prior to GX8 use 16MP. If I compare a still picture took by both GX8 and GX7, what's the difference? Would I get

    A larger picture? Meaning both length and width are greater but the density of dots (pixels) remain the same. Or

    The "same size" of picture? Both length and width are relatively the same but the density of dots (pixels) are condensed. Therefore I have more detail.

    And would the same logic apply to sensors made by other manufacture such as 24.3MP A7ii?

    Thank you!
  2. tkbslc

    tkbslc Mu-43 Legend

    The sensor size and field of view stays the same. The sensor has more densely packed pixels to allow it to fit 20 million instead of 16 million. It's the same with every system.

    THe benefit is mainly being able to print larger at the same DPI or cropping farther while maintaining the same detail.
  3. Hugo

    Hugo Mu-43 Regular

    Sep 28, 2011
    Thanks! So can I assume that I can zoom in to get more detail (vs. 16MP)?
  4. mattia

    mattia Mu-43 Hall of Famer

    May 3, 2012
    The Netherlands
  5. tkbslc

    tkbslc Mu-43 Legend

    By cropping you can. But don't get too excited as it's only the equivalent of 11% more "reach" and a lot of it depends on whether your focus and lenses were sharp enough in the first place. .
  6. Hugo

    Hugo Mu-43 Regular

    Sep 28, 2011
    Thanks guys! Appreciated!
  7. MedicineMan4040

    MedicineMan4040 Mu-43 Veteran Subscribing Member

    Sep 2, 2015
    East TN
    Some of us (me) think this sensor is one of the new ones made by Sony for mFT and thusly there is to my eye
    a bit more DR, how much I cannot say as of yet and I'd venture DXO will give us the true difference if any soon
    as they can do their studies.
    That increased concentration of pixels also means more pixels concentrated in the center of the sensor and it is
    the center of the sensor that is straight in line with the center of the lens (unless of course your lens is decentered)
    and most (I'd bet 99%) lenses are sharpest in the center..so it's a win win.
    Now couple that with the new primo lenses available, like the 40-150 Oly 2.8 Pro, the 300 F4 to come, and the
    only announced 100-400Pan-Leica G and the potential goes way up for the little mFT world.
    And that is a good thing for my knees and back!
    • Like Like x 2
  8. pdk42

    pdk42 One of the "Eh?" team

    Jan 11, 2013
    Leamington Spa, UK
    If you view at 100%, the GX8 images will be bigger (assuming you have a monitor big enough to display it). There are more pixels in width and height (approx 11.8% extra in each dimension).
  9. AcridSaint

    AcridSaint Mu-43 Regular

    Feb 25, 2014
    North Carolina
    I don't know if it's been settled yet who makes the sensor, but I do know that Panasonic also claims more dynamic range in this new sensor, so I don't think your impression is wrong.
  10. Hugo

    Hugo Mu-43 Regular

    Sep 28, 2011
    Wait...This contradicts to what tkbslc was saying. One is have the same size but with more detail (condensed pixels) one is larger size with the same density of the detail. Let me use an example. By the way, the real world technology might not work this way. I'm just trying to get a general idea.....

    Assuming there’s an old censor generates 9 pixels, 3 x 3 and at 100% I have 2cm in length and 2cm in width with 1cm between each pixel. The advanced sensor will yield 25 pixels which of the following is correct?
    1. The size of the picture is unchanged. I will have a picture of 2cm x 2cm but with the distance between pixel shrinks to 0.5cm (4 * 0.5 = 2cm). Therefore it yields more detail coz I can zoom in more.

    2. The size of the picture increased. I will have a picture of 4cm x 4cm because the distance between pixels remains the same @ 1cm. Therefore I don’t get more detail but a larger size of the picture.
  11. b_rubenstein

    b_rubenstein Mu-43 All-Pro

    Mar 20, 2012
    Melbourne, FL
    Pixel density (assuming all else is equal) determines maximum capture resolution. The size of the picture is somewhat arbitrary and depends on viewing magnification.
  12. The SENSOR size is the same but the SENSOR's pixels are smaller -- your computer's pixels are unchanged, therefore, larger photo with more detail.
  13. b_rubenstein

    b_rubenstein Mu-43 All-Pro

    Mar 20, 2012
    Melbourne, FL
    Smaller pixels do not give more detail/resolution. More pixels in the same linear space gives more detail/resolution. It does this because it raises the spatial frequency of the sensor, which drives the Nyquist frequency up.
  14. pdk42

    pdk42 One of the "Eh?" team

    Jan 11, 2013
    Leamington Spa, UK
    Well, what I meant is this... Viewing an image file on a monitor at 100% means that 1 pixel on the sensor = 1 pixel on the screen (assuming no down-scaling in camera). So, if two identically-sized but different pixel count sensors capture the same scene and you then view them 100% on a monitor, then the image from the sensor with the biggest pixel count will be bigger on screen. Of course, this only applies when both images are viewed at the same magnification on the screen (I chose 100% because that's what most of us do when inspecting photographs carefully).

    If you scale them to the screen dimensions (or print them to a given paper size), then of course they'll be the same size, but the photo from the higher Mp sensor will have lower magnification.

    Does that make any sense!!??
  15. D MATIC

    D MATIC Mu-43 Regular

    Jul 18, 2012
    Both 1 and 2 are correct except for the last sentence in 2.

    You can open up sample images found online

    GX7 jpg is 4592px x 3448px
    GX8 jpg is 5184px x 3888px

    If you view the GX8 image down to the same exact size of the GX7 image side by side, you would have to zoom out on the GX8 image to match the GX7 smaller size, therefore giving you more resolution to work with.
    • Agree Agree x 1
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