Light Falloff in larger sensors - How bad is it really?

Discussion in 'Digital Discussion & Q&A' started by OmlessWanderer, Mar 17, 2007.

  1. OmlessWanderer

    OmlessWanderer TPF Noob!

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    The subject pretty much sums up my question.

    I read this: http://www.cleanimages.com/DDBlog-ShouldNikonMakeA35mmSizedSensor.asp

    He doesn't seem to have anything aside from anecdotal evidence. No photo comparison anyway. So how bad is the light falloff and [FONT=Verdana, Arial, Helvetica, sans-serif]edge chromatic aberration on these larger sensors anyway? Anyone have a link to where this comparison was already done?

    Especially in the pro-sumer and just under category. (i.e. compare Nikon d70, d80, d200 vs Canon
    [/FONT] 5D & 30D)
     
  2. EOS_JD

    EOS_JD TPF Noob!

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    There's many examples of this around the web. Do a search in google on "5D light fall off" or "5D vignetting" - Light fall off (or vignetting) is more common on FF cameras (depending on the lens and aperture you use) than with smaller sensors like the Nikons and Canon crop cameras like the 20D/30D (they all have similar sized sensors). The 5D is the only larger sensor in the list you made above. It's a full frame camera and together with somethig like a 24-105f4L IS lens wide open there may be some darkness in the corners but stop it down a little and it all but disappears.

    All Nikon cameras you note above as well as the Canon 20D/30D/XT/XTi (and a couple of others) have APS-C sized sensors which are smaller than their FF equivalent. I've not noticed any light fall off on any of my lenses and I have lenses ranging from 10-300mm although all quality lenses (inc 3 Ls).

    With the 5D because of the larger sensor, the lens choice is critical and you need good glass.
     
  3. OmlessWanderer

    OmlessWanderer TPF Noob!

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    Really? The Canon page calls the 30D sensor a "large area sensor" (link) and specifically refers to the Rebel series sensors as APS-C...

    Thats another think I've had some trouble with... dpreview.com has sensor specs on their page. For example it lists the following
    5D: 35.8 x 23.9 mm CMOS
    1D Mark-III: 28.7 x 18.7 mm

    Why is the 1D Mark-III sensor smaller when they're both supposed to be full frame sensors? Does this number have anything to do with the physical size of the sensor?
     
  4. EOS_JD

    EOS_JD TPF Noob!

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    Canon only have 2 FF sensor cameras at the moment. 1Ds MkII and 5D. the 1MkII N and now the 1D MkIII have AS-H sized sensors that are larger than the likes of the 30D etc.

    10D/300D/XT/XTi/20D/30D all have APS-C sized sensors. These are very large compared to any compact camera but are smaller by some margin than the FF equivalents.

    dpreview should show all sensor sizes.

    THe 1DMkIII has a 1.3x crop - it's NOT a FF camera - where did you read this?

    A FF camera has roughly the same size sensor as a negative from a 35mm film camera - 35mm roughly.

    So as you see the 5D has a 35.8mm x 23.9mm sensor (very close to the negative size of a 35mm film camera).

    Hope that helps.
     
  5. EOS_JD

    EOS_JD TPF Noob!

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    Here's some sensor sizes

    10D - 22.7 x 15.1 mm CMOS sensor - 1.6x crop - APS-C
    XT - 22.2 x 14.8 mm CMOS sensor - 1.6x crop - APS-C
    20D - 22.5 x 15.0 mm CMOS sensor - 1.6x crop - APS-C
    XTi - 22.2 x 14.8 mm CMOS sensor - 1.6x crop - APS-C
    30D - 22.5 x 15.0 mm CMOS sensor - 1.6x crop - APS-C

    5D - 35.8 x 23.9 mm CMOS sensor Full Frame (no crop)
    1DMkII N - 28.7 x 19.1 mm CMOS - 1.3x crop - APS-H
    1D MkIII - 28.1 x 18.7 mm CMOS sensor- 1.3x crop - APS-H
    1Ds MkII - 36 x 24 mm CMOS (full 35 mm frame)


    Nikon
    D40 - 23.7 x 15.6 mm CCD sensor - 1.5x Crop - APS-C
    D50 - 23.7 x 15.6 mm - 1.5x Crop - APS-C
    D70 - 23.7 x 15.6 mm - 1.5x Crop - APS-C
    D80 - 23.6 x 15.8 mm CCD sensor - 1.5x Crop - APS-C
    D200 - 23.6 x 15.8 mm CCD sensor - 1.5x Crop - APS-C
    Even their top line cameras are 1.5x sensors.

    D2X - 23.7 x 15.7 mm CMOS sensor - 1.5x Crop - APS-C

    The 30D APS-C sensor is therefore very similar to all the Nikon sized APS-C sensors.

    Only 2 DSLRs currently have FF sensors - 5D (12.8p) and 1Ds MkII (17Mp)
     

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