Is 8MP the limit for APS size sensor DSLRs?

Discussion in 'Digital Cameras' started by SimonLW, Sep 26, 2005.

  1. SimonLW

    SimonLW Guest

    From my experimentation, it appears that there is not much to be gained by
    making higher resolution APS sized sensors for DSLR cameras. Unless I used
    high quality fixed focal length lenses on a tripod, I was not able to
    squeeze out any useful additional resolution. Even with a 6mp DSLR,
    difference between good and great lenses is quite evident.

    With all the resolution concentrated in the small APS sized sensor, requires
    more resolution from the lens then does a high resolution camera, such as
    Canons 16.6 MP body. For example, if the 20Ds 8mp sensor pixel size and
    pitch were kept the same, but made into a full frame sensor, the sensor
    would be 21MP. This is because a 36x24mm full frame sensor has about 2.6
    times the area than does the APS sensor.

    Given this fact, the APS sized sensor has run it course resolution wise. It
    would seem that a way for making lower cost full frame sensors is the best
    route for digital SLRs.

    What do you think?
    -S
     
    SimonLW, Sep 26, 2005
    #1
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  2. SimonLW

    Hans S Guest

    I think the statement has as much value as '640K is more memory than
    anyone will ever need'. History will undoubtedly prove you wrong ;-)

    Needless to say there already is a 12MP APS digital on the market ...
     
    Hans S, Sep 26, 2005
    #2
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  3. SimonLW

    SimonLW Guest

    Yes, but as I previously stated, unless quality lenses are used and a tripod
    to steady the camera (or fast enough shutter speed), there is nothing real
    gained. Putting anything but quality glass on the DX2 is going to gain
    nothing over the same lens on a 8mp camera.

    Dpreview's comment about the APS sensor using the sharper central area of
    the lenses' image circle is a good point though.
    -S
     
    SimonLW, Sep 26, 2005
    #3
  4. So far, so good, but:
    Is it? It sounds dead wrong to me.

    (1) For (decent quality) telephoto lenses, there largely isn't a sweet spot:
    the MTF charts are flat all the way out. So there's no effect here.

    (2) For normal to wide lenses, the quality goes down as the focal length
    gets shorter. The 35mm lenses are much better lenses than the 24mm lenses
    (the MTF charts fall off faster). So using a 24mm lens on a cropped camera
    you'll be seeing very similar MTF falloff at the corners as the FF user sees
    with his 35mm lens.

    I don't see any improvement at all...

    David J. Littleboy
    Tokyo, Japan
     
    David J. Littleboy, Sep 26, 2005
    #4
  5. I _HATE_ Tamron.

    My wife wants my 300D, so won't be complaining if I buy a 5D. So I was going
    to let her have the Tamron 28-75/2.8.

    So I'm lurking on a 1Ds2 group, and someone asks 'what's a good wide angle',
    and some obnoxious twit responds 'The Tamron's as good as it gets at 28mm,
    if you don't need any wider' and provided pointers to images to prove it.

    Which leaves me without a lens I'm willing to give the wife. And she's not
    going to be amused by a lensless camera...
    Yes. See my other note on this.

    David J. Littleboy
    Tokyo, Japan
     
    David J. Littleboy, Sep 26, 2005
    #5
  6. SimonLW

    W.E. O'Neil Guest

    Well, there is the perceived magnification, which is a very worthy point of
    consideration.
    Your example is incidental (taking on faith that it's accurate in the first
    place).

    When you get to wide angle lens in sizes of say 17,15,14,12, 10.5, the
    advantage of shooting through the center of the lens is easily recognized.
    Bottom line is that the sensor basically does what any decent
    post-production technique will do......which is crop the soft corners. And
    depending upon how much crop one would impose on the full frame image to
    eliminate the corners, the small sensor shot might apply more pixel power to
    the resulting image.

    Take a look at the pics you cited in the thread about full sensor shooting
    wide angle. I thought the corners (glass edges) of those pics were awful.
    Muddled and soft. Sorry, but I could not for the life of me figure out why
    anyone would post those pictures as proof. It's not the fault of the sensor,
    but rather the realities of shooting edge to edge through wide angle glass.
    The sensor probably did a very nice job of resolving exactly what light was
    projected on it, but the result was the same....shooting edge to edge on a
    sensor develops the same shortcomings in glass as shooting edge to edge on
    emulsion. Had that same image been shot through the center of a 12mm lens
    the evident edges would be far better and accurate, and the perspective
    would have close to equal.

    The claim that smaller sensors (given adequate pixel count and camera
    software) creat some improvement by shooting thru the sweet spot is a
    reality.
     
    W.E. O'Neil, Sep 27, 2005
    #6
  7. What do I think? I think that if a little knowledge is a dangerous thing,
    you're a walking powderkeg.
     
    Psych-O-Delic Voodoo Thunder Pig, Sep 27, 2005
    #7
  8. SimonLW

    Dirty Harry Guest

    A tripod and fast enough shutter speed?? If you have motion blur if doesn't
    matter what you are using, this is just good techinque and should always be
    used if needed.
     
    Dirty Harry, Sep 27, 2005
    #8
  9. SimonLW

    SimonLW Guest

    As a side note, the resolving power of short focal length, compact lens
    systems can be very high. This is almost never realized in interchangable
    SLR lenses perhaps because of the retrofocus design. At least Canon EF-S
    lenses (Lenses for their APS dSLRs), the ability has not been proven to me)
    .. The absolute resolution of the lens on typical compact digital cameras has
    to have very high due to the fine pitch of the sensor cells in the array.
    For example, the number of pixels per mm on a 6mp APS sensor is only about
    135. On the DX2, it is around 200 (the finest APS pixel pitch to date that
    I'm aware of). The Canon 1Ds Mark II (16.7 mp) only has around 138 pixels
    per mm. Putting the lens edge performance argument aside, It requires about
    the same resolving power from the lens as does a 6 mp digital rebel. The
    typical 4mp compact will have around 430 pixels per mm so the lens must be
    quite good!

    The point is that higher resolution APS sensors can possible in lower cost
    SLRs if high quality lenses can be developed for it at an affordable price,
    otherwise, I see 8mp APS sensors to be the end of the line in affordable
    interchangable lens SLRs (aside from the 5 grand DX2 and costly high
    performance lenses).
    -S
     
    SimonLW, Sep 27, 2005
    #9
  10. SimonLW

    Stacey Guest

    Yep yet he said our "Jaw should drop"?
     
    Stacey, Sep 28, 2005
    #10
  11. SimonLW

    Stacey Guest

    I think there is more to image quality than just resolution.
     
    Stacey, Sep 28, 2005
    #11
  12. SimonLW

    SimonLW Guest

    Of course, but why bother with medium and large format and why bother
    progressing beyond 3mp dSLRs?
    -S
     
    SimonLW, Sep 28, 2005
    #12
  13. SimonLW

    SimonLW Guest

    Of course, but why bother with medium and large format and why bother
    progressing beyond 3mp dSLRs?
    -S
     
    SimonLW, Sep 28, 2005
    #13
  14. SimonLW

    Stacey Guest

    Exactly. You do understand -most- people shooting medium and large format do
    it for reasons other than more resolution right?
     
    Stacey, Sep 29, 2005
    #14
  15. SimonLW

    Dirty Harry Guest

    LOL
     
    Dirty Harry, Sep 29, 2005
    #15
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