What the reviewers don't view...

Discussion in 'Australia Photography' started by Focus, May 22, 2008.

  1. Focus

    Focus Guest

    It's warm and cozy in the perfectly lit studios of most reviewers, but do
    you really get a really good "buying advise"?

    I don't think so. The 40D Canon I had, seemed OK at first. Trouble started
    when I tried to make pictures with any kind of sunlight: the WB was all over
    the place and the difference between some shots with the same light,
    aperture and subject, sometimes differ as much as one stop!

    Here's a picture of the south bank of the river:

    http://photos-of-portugal.com/Canon1.JPG

    Here's another, exactly the same place and time, just 3 secs apart:

    http://photos-of-portugal.com/Canon2.JPG

    Now you would think, that the second picture is lighter, because the camera
    is more turned to the sun.... BEEP! It's actually turned away from the sun.
    But all smart people already understood that, since the picture is of the
    south bank ;-)
    The exposure increased form 1/400 to 1/250. Close to 1 stop, and the sky is
    washed out, including some masts on top of the hill.

    Case in point: not one review shows this, because they all use the studio
    set-up.
    So you'll just have to take a camera out for a spin, before you decide which
    is good and which is not.
    This one clearly is not.
     
    Focus, May 22, 2008
    #1
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  2. Focus

    OldBoy Guest

    PS CS3 left the full EXIF in a bitbucket :)
    The center points of the picture is different, that may be the culprit.
     
    OldBoy, May 22, 2008
    #2
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  3. Focus

    Dev/Null Guest

    Buy a clue! The light is clearly different, it appears the sun broke out
    from the clouds. The studio is the best place to test and compare cameras as
    natural daylight is too variable and unreliable
     
    Dev/Null, May 22, 2008
    #3
  4. Focus

    Focus Guest

    Not when you use evaluative metering. Centre weighed or spot: yes,
    understandable. Not good, but understandable ;-)

    I uploaded straight out of DPP, no change.
    Just reload.
    I think now it's even worse.
     
    Focus, May 22, 2008
    #4
  5. Focus

    TRoss Guest


    Just curious. Is the camera set up for auto exposure bracketing?
    Shooting in Aperture Priority with a 1-stop AEP will give you the
    results you got.

    TR
     
    TRoss, May 22, 2008
    #5
  6. Focus

    Steve Guest

    There's something stranger than just that going on here. The aspect between
    the two pix is different, and not from just having the centre point on a
    slightly different spot. They are clearly not taken from exactly the same
    place. One of the pix seems squished somehow - try overlaying any one point
    on one of the pix onto the same point on the other and you will see what I
    mean. The amount of angular change of position might accont for this.
    Strange.

    Steve
     
    Steve, May 22, 2008
    #6


  7. The OP wrote that the pix were taken in the same light.
    Looks to me the first was in hazy light and in the second the sun had come
    through fully.
     
    G Paleologopoulos, May 22, 2008
    #7
  8. Focus

    Focus Guest

    LOL! I think I would remember going thru the menu and putting it on AEB.
    Besides, then I would have 3 different ones.

    Maybe it's SEB: Surprise Exposure Bracketing ;-)
     
    Focus, May 22, 2008
    #8
  9. Focus

    Focus Guest

    Nope. Not a cloud in the sky. look at where there's a space between the
    houses. Right above there's a bush with shadow. looks the same in both pics,
    but of course less bright. Same at the front of the ship. There's a little
    reflection from the top and a little lower. Same in both.
     
    Focus, May 22, 2008
    #9
  10. Not true. If the drive setting is at one shot you will move through the
    brackets one at a time.
     
    thepixelfreak, May 22, 2008
    #10
  11. Focus

    Dev/Null Guest

    The light on the building and boats is clearly different, look at the
    highlights and shadows. Exposure can't create that.
     
    Dev/Null, May 22, 2008
    #11
  12. Focus

    Focus Guest

    I took another look at different pictures the same time and guess what? It's
    WAY OFF!

    Much more difference in scene, but the values are the same:
    http://photos-of-portugal.com/Canon3.JPG
    http://photos-of-portugal.com/Canon4.JPG

    Here less difference in scene, but one at 1/500 sec and f7.1, the other
    1/500 and f8
    http://photos-of-portugal.com/Canon5.JPG
    http://photos-of-portugal.com/Canon6.JPG


    Here much more difference, but the same values:
    http://photos-of-portugal.com/Canon7.JPG
    http://photos-of-portugal.com/Canon8.JPG

    All in all, I think the problem is, that Canon (or at least the sample of
    the 40D that I had) hates direct sunlight.
    Other pictures of the same place at early evening before sundown are OK.
    I checked similar pictures I took with the Nikon D40 and D300 and the Sony
    A350, but they don't have any problems like this.

    Maybe it's time to put a big sticker on the box:

    "KEEP OUT OF DIRECT SUNLIGHT"
     
    Focus, May 22, 2008
    #12
  13. Focus

    ben brugman Guest

    Now let's estimate the amount of movement.
    The two boats do not show movement. The have about the same distance in both
    pictures. They are fairly close together and look moored. So I assume that
    they do not move.

    Behind the right boat an extra car is visible in one of the picture. (Two
    cars between the boat and the red car in one picture, only one and a part on
    the other). The difference in distance is about 3 meters extra. A very rough
    estimate is the the relative distance from the cars to the boat and from the
    boat to the observer is about 5 times as much.
    (This is a very crude estimate). If the cars have not moved and the boot has
    not moved and the distance between the cars and the boat is about 1/5 of the
    distance between the cars and the camera, the camera must have moved about
    15 meters.

    According to the exif data the pictures are taken 3 seconds from eachother.
    This would give a speed of 15 meters for 3 seconds. or 5 meter a second.
    that's 3600/1000*5 = 18 km/hour. Quite some speed to take pictures in. Maybe
    during the measuring the camera was pointed and something different in on of
    the pictures.

    From the pictures I do see the movement at a lot of places, so it's not only
    the boats that show the movement. But's it's difficult to estimate the
    relative distances, with the boat and cars, the distances can be estimated
    (very roughly), that's why I have used those. But there is movement from my
    calculation even movement at some speed. So the pictures must have been
    taken in 'Haste', then consistent results should not be expected.

    Maybe the OP can clearyfy what realy happend. I detend movement, I estimate
    speed (roughly). But might be completely wrong in estimating the distances.
    (and therefore the speed).


    Ben
     
    ben brugman, May 22, 2008
    #13
  14. Focus

    Focus Guest

    Ahum, very accurate Sherlock!
    As I don't have floating shoes, it might be evident I took the shots from a
    ship.
    And likely the speed is correct.
    Still doesn't come close to explain the difference.
    Your turn, Sherlock!
     
    Focus, May 22, 2008
    #14
  15. Focus

    Dica Photo Guest

    The OP is a troll.
     
    Dica Photo, May 22, 2008
    #15
  16. Focus

    ben brugman Guest

    Why not from the opposite shore ? The pictures do not reveal that. The hight
    you are on is about the same as the shore where the cars are standing. If
    you stand close enough to the edge and with a 85 mm you do not even have to
    be close, you do not get any 'shore' line of your side.
    From the pictures I can not see from what or were the pictures where taken.
    My first assumption was that they where taken from the opposite on the
    shore. The two pictures do not reveal that. The speed indicates for me
    something faster that walking. Could be a bike, a car or something else.
    Floating shoes did not come to my mind, but yes a ship would be able to do
    18 km/hour.
    One of the pictures is not as wel sharp as the other, (movement or not
    focused correctly), so one possibility would be that moving the camera
    around you could take pictures of almost the same scene but measuring
    something else.

    (I have made pictures where the exifs shows the same focal length, but the
    pictures show completely zoomed in and completely zoomed out, so working
    fast enough, it can be that the measurement (exif) does not correspond with
    the pictures. Because of the movement this is not exactly a repeateble
    experiment).

    But if in general the camera does produce pictures where the results are not
    consistent there is a problem because you can not anticipate enough as a
    fotographer.
    Total consistency can not be expected. But if you can reproduce this
    difference (it's less than a stop), with a more stable situation (tripod)
    and a fixed framing. I would say that the variation of 2/3's of a stop is a
    bit to much for a decent camera.

    Can't exactly see were the sun is in the pictures, could be that you might
    benefit from a good sunshade (on the lens or external). If the sun is
    hitting the lens directly or by a reflexion (possible on a ship) this might
    be the cause. The reflexion could even be happening during the metering and
    not effect the picture. So again reproducing this with a more fixed setting,
    would indicate that the camera is wrong.

    So from the shown pictures I can not say that the camera made the
    difference, this could wel be but the pictures are not enough proof for
    this.

    So the difference is not explained, but because of the circumstances
    (unstable), the conclusion that it must be the camera, is not correct. Yes
    it could be the camera, but these pictures on their own are not conclusive.

    I hope for you that you can not reproduce this and thereby proof that this
    was just a fluke. Otherwise you have to accept this or change your camera.

    ben
     
    ben brugman, May 22, 2008
    #16
  17. Focus

    Focus Guest

    I already changed to a Sony A350 that doesn't have this problem with the
    same time of day, same ship and same shore.
    You can look at the other pictures in the posting below.
    Should be more then evident, there's something wrong.
    But I don't really care anymore: the Sony is very good at metering and
    rarely gets it wrong.
    It reminds me very much of the Nikon D300, as far as metering goes.
    You're right about the fact that they can't be expected to be dead on
    always. But 95% would be nice ;-)
     
    Focus, May 22, 2008
    #17
  18. Focus

    TRoss Guest

    I think I would remember, too. But on more than one occasion I've set
    the AEB and forgot to reset when it was no longer needed. It isn't as
    as bad as forgetting to reset exposure compensation, which doesn't
    reset on my camera when it's turned off, but it can still make a mess
    of things.
    Not necessarily. If the drive is set to one shot, you have to press
    the release to move through the brackets. You could have taken two of
    the three shots in the bracket.


    TR
     
    TRoss, May 22, 2008
    #18
  19. Focus

    Colin_D Guest

    You don't say anything about the lens you used. Was it a Canon lens, or
    a third-party job?

    I have seen lenses where the aperture closes down differently each time,
    or doesn't open fully after, upsetting the exposure measurement. Whether
    it was sticky blades or crappy construction wasn't clear.

    When the camera calculates the exposure and sends the aperture data to
    the lens, the aperture is expected to close down accurately - if it
    doesn't, you get the exposure variation you have in your shots.

    One further possibility is if you allow stray light into the viewfinder,
    it will shorten the exposure. Wearing glasses that sit some distance
    from the eye can be a subtle source of variable exposure, by letting
    light in from the side. This is an often overlooked problem when the
    camera is on a tripod and the VF is not covered.

    I think blaming the camera here is just a little premature.

    Colin D.
     
    Colin_D, May 22, 2008
    #19
  20. Focus

    Focus Guest

    OK, to be absolutely clear about it. I KNOW it wasn't in bracketing, because
    I NEVER use bracketing.
    Clear enough?
     
    Focus, May 23, 2008
    #20
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