camera going crazy or OP error????

BountyphotographerBountyphotographer Registered Users Posts: 413 Major grins
edited June 5, 2012 in People
Hello,

I had problem with this lens before 24-70 2.8 Sigma with sticking aperture but was told that it was fixed. Anyhow I took many pictures with pretty good exposure when suddenly everything goes dark.
I checked the lens it was fine, I overexposed to the max and barely got something decent.
I m glad I have software to correct it other wise lots of shot would have been ruined.

can you help me???

I have two examples of what Im speaking of www.bph.smugmug.com / clients/ pictures


password smugmug


Thanks

Bounty
:photo

Comments

  • RyanSRyanS Registered Users Posts: 507 Major grins
    edited June 5, 2012
    Well, you certainly didn't make it easy to find the pictures. :D Next time please consider posting them in to the thread.

    The difference is not a sticky aperture, it is shutter speed. One is shot at 1/400 @f/8, the other is shot at 1/2500 @f/8. Just a few stops different there. mwink.gif
    Please feel free to post any reworks you do of my images. Crop, skew, munge, edit, share.
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  • OverfocusedOverfocused Registered Users Posts: 1,068 Major grins
    edited June 5, 2012
    Yeah that little adjustment knob up there... em... don't bump it :D
    www.overfocused.com
  • BountyphotographerBountyphotographer Registered Users Posts: 413 Major grins
    edited June 5, 2012
    sorry about the pictures.
    I never said that it was sticky aperture.
    I also knew about the shutter speed, I guess that Im not very good at expressing myself.
    I wanted to know why?
    I was shooting at the same distance aiming the same subject, yet the shutter changed drastically??
    Could it be because of the white shirt under the sun???headscratch.gifscratchheadscratch.gif
    :photo
  • T. BombadilT. Bombadil Registered Users Posts: 286 Major grins
    edited June 5, 2012
    Your SmugMug images indicate exposure was "auto". So how did you overexpose intentionally (mentioned in your OP)?

    Could be that you are using spot metering (white shirt in the middle of the photo caused the overall image to be underexposed, gray shirt in the middle brought exposure back to nearer expected value).

    Bountyphotographer wrote: »
    sorry about the pictures.
    I never said that it was sticky aperture.
    I also knew about the shutter speed, I guess that Im not very good at expressing myself.
    I wanted to know why?
    I was shooting at the same distance aiming the same subject, yet the shutter changed drastically??
    Could it be because of the white shirt under the sun???headscratch.gifscratchheadscratch.gif
    Bruce

    Chooka chooka hoo la ley
    Looka looka koo la ley
  • divamumdivamum Registered Users Posts: 9,021 Major grins
    edited June 5, 2012
    - You were shooting in high contrast light - some areas are in shadow, some are in shade.

    - It's not exactly the same shot; there was at least enough time between them for the group position to change

    - You're using automatic mode, therefore the camera is deciding what to do, not you; since your aperture was f8, we have no idea what you actually focused on, so it could have been anything from the white shirt in full sun, to the shadows on the black shirt.

    These are exactly the kinds of light conditions where shooting fully automatic isn't the best choice. If you don't want to shoot fully manual, then aperture-priority or Auto ISO (if your camera has it) will yield more controllable results in this situation.

    Short answer? Based on these two shots, operator error. However, if you're worried about the lens/camera, then do some testing in controlled situations to see if you can reproduce the problem, at which point you can troubleshoot it further thumb.gif
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  • BountyphotographerBountyphotographer Registered Users Posts: 413 Major grins
    edited June 5, 2012
    Wow!! I could have sworn that I was shooting aperture and shutter priority. I took so many pictures and kept changing priority because of the wind and background. funny that I left it on auto I usually dont trust that priority at all????
    Its hard to believe that focusing from white to gray the exposure jumped so much. Its like day and night.
    I'll do more testing

    thank you

    Bounty
    :photo
  • T. BombadilT. Bombadil Registered Users Posts: 286 Major grins
    edited June 5, 2012
    Aperture Priority, Shutter Priority, Program, and "full automatic" are all automatic modes where the camera's meter is choosing total exposure (as it does if auto ISO is in play, also).

    I only looked once, but you (or the camera) chose f/8 for both shots, correct? That could happen with Aperture Priority or full Manual. The shutter speed changed from one shot to the other. That happened because the operator changed the shutter setting, or the camera changed the shutter setting (either because the meter told it to, or a malfunction).

    A malfunction is possible, but isn't all that likely.

    Take a look at the metering method you are using. Your camera is probably capable of "Spot", "Center Weighted", and "Matrix" (or 'average' or something similar).

    Unless you were on full manual and accidentally hit the shutter dial, the camera's meter is determining the shutter speed. If the meter was set on "Spot", it made the exposure decision based on what it saw at that spot (in one photo a white shirt, in the other photo a gray shirt).

    The camera wants the metered spot to be a mid-tone gray in the final photo. If the metered spot is a mid-tone gray shirt, the photo will look good overall (that seems to be what happened with the photo with the man in the middle). If the metered spot is a white shirt in the sun, the camera will try to make that darker until it is mid-tone gray. You make one exposure, so making that white shirt a medium gray means making the entire photo darker - which is what you saw in the photo with the woman in the middle.

    Bountyphotographer wrote: »
    Wow!! I could have sworn that I was shooting aperture and shutter priority. I took so many pictures and kept changing priority because of the wind and background. funny that I left it on auto I usually dont trust that priority at all????
    Its hard to believe that focusing from white to gray the exposure jumped so much. Its like day and night.
    I'll do more testing

    thank you

    Bounty
    Bruce

    Chooka chooka hoo la ley
    Looka looka koo la ley
  • BountyphotographerBountyphotographer Registered Users Posts: 413 Major grins
    edited June 5, 2012
    Now we are talking.
    I know for a fact that it was on spot .
    A week ago I was fooling around and forgot to put it back on center weighted mode.
    Ill try to duplicate that problem this week-end under harsh light, which is not too difficult in Southern California.

    Thank you

    Bounty


    PS: Funny to forget the 101 of photography while trying to shoot our best :bash:bash
    :photo
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