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Thread: exposure question on olympus XA

  1. #1

    Default exposure question on olympus XA





    hello guys, i used my olympus XA camera to take this two picture, they were taken one after another one, i remember i was trying to use different aperture setting, one is 2.8 and one is 16. it was an late evening scene. But i wonder why such a big difference?

    to me the grey tone photo isn't like what i was seeing (late evening), i just can't figure out why 2 photo taken at different aperture in a split second and can look so different? i am not sure which is taken at f2.8 or f16..

    Can someone enlighten me? i just find it very strange..since i encounter under or over exposure..but why 2 different tones without using any filter? or issit the scanning? it seems other photo ok.

    both picture seems exposure ok for me..weird!

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    Default Re: exposure question on olympus XA

    Quote Originally Posted by LENS View Post




    hello guys, i used my olympus XA camera to take this two picture, they were taken one after another one, i remember i was trying to use different aperture setting, one is 2.8 and one is 16. it was an late evening scene. But i wonder why such a big difference?

    to me the grey tone photo isn't like what i was seeing (late evening), i just can't figure out why 2 photo taken at different aperture in a split second and can look so different? i am not sure which is taken at f2.8 or f16..

    Can someone enlighten me? i just find it very strange..since i encounter under or over exposure..but why 2 different tones without using any filter? or issit the scanning? it seems other photo ok.

    both picture seems exposure ok for me..weird!

    I experience the same problem too but don't know why the picture turned out this way.

  3. #3

    Default Re: exposure question on olympus XA

    I was wondering issit because for olympus XA, there is a limitation of fastest shutter speed that may cause over exposure, but both photo looks ok.

    but it seems different aperture setting shouldn't contribute 2 different photo like this right?

    and so could it be something happened in scanning process? i scanned whole rolls in shop, and it seems everything ok..this 2 photos come as right sequence then i remember i tried something to see what different aperture may makes difference on olympus XA..

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    Default Re: exposure question on olympus XA

    Quote Originally Posted by LENS View Post




    hello guys, i used my olympus XA camera to take this two picture, they were taken one after another one, i remember i was trying to use different aperture setting, one is 2.8 and one is 16. it was an late evening scene. But i wonder why such a big difference?
    I see only differences in colour. Are these prints from negative film? In this case, an easy answer: the prints underwent radically different colour correction during printing, probably under control of "intelligent" software.

    If there are exposure problems, there are two factors to consider: 1) the meter of the camera may be out of range in low light, and 2) CdS photoresistors can take a long time to respond (minutes) in dim conditions. Note that the XA feeds the selected aperture to the meter by shading the sensor, i.e. dimming the light to be measured.

  5. #5

    Default Re: exposure question on olympus XA

    Hi little wolf, the pictures are scanned from negative to cd jpg..
    actually i have been wondering what is the reason, will different exposure will have such a color shift? the blue version is normal to me, as usually late evening scene. the grey version is like something took on day light..which is not, i took them a split second.

    if you ask me, i also can't tell which is 'bad' exposure, i just feel like they are taken at different days..what else could be the reason?ha

    Quote Originally Posted by LittleWolf View Post
    I see only differences in colour. Are these prints from negative film? In this case, an easy answer: the prints underwent radically different colour correction during printing, probably under control of "intelligent" software.

    If there are exposure problems, there are two factors to consider: 1) the meter of the camera may be out of range in low light, and 2) CdS photoresistors can take a long time to respond (minutes) in dim conditions. Note that the XA feeds the selected aperture to the meter by shading the sensor, i.e. dimming the light to be measured.

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    Default Re: exposure question on olympus XA

    Quote Originally Posted by LENS View Post
    Hi little wolf, the pictures are scanned from negative to cd jpg..
    actually i have been wondering what is the reason, will different exposure will have such a color shift? the blue version is normal to me, as usually late evening scene. the grey version is like something took on day light..which is not, i took them a split second.

    if you ask me, i also can't tell which is 'bad' exposure, i just feel like they are taken at different days..what else could be the reason?ha
    Like i say it happen to me but being blue could i be of a lower temperature?
    But again it was take together at a spilt second so...uhm..

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    Default Re: exposure question on olympus XA

    Quote Originally Posted by LENS View Post
    Hi little wolf, the pictures are scanned from negative to cd jpg..
    actually i have been wondering what is the reason, will different exposure will have such a color shift?
    Well, is the exposure that different in the first place? In the pictures you posted, the shadow detail (e.g. under the bridge) seems comparable to my eye, which makes me suspect there is not much of a difference. How do the negatives compare when you look directly at them? A significant difference in exposure should be quite obvious even to the untrained eye when looking at the negatives side by side.

    If a negative was e.g. grossly underexposed, colour shifts could easily occur, (either due to the nonideal transfer curves of the film, or due to slight misadjustment of the scan parameters which may become exaggerated), but somehow I have my doubts that this is the case here.

    Did you do the scan from negative yourself, or did a minilab do that for you? If you did it yourself, you can try to rescan while keeping all parameters fixed (turn off any automatic adjustments). If it was done by a lab, I would expect the same colour correction functions to kick in as if you had made prints - the difference between a CD and prints is only the device on which the manipulated image is output.

    Automatic adjustments can be pretty unpredictable, a slight difference may push some parameter over a threshold where the software interprets the picture differently (and thus corrects differently). I.e., the software could consider one picture a night shot for which a blue cast is normal, and another one for a daylight shot that for some reason has a blue cast that needs to be corrected. You get similar effects with matrix metering in cameras, leading to the strange outliers in exposures that are reported every now and then in reviews.

  8. #8

    Default Re: exposure question on olympus XA

    Quote Originally Posted by dotaboy View Post
    Like i say it happen to me but being blue could i be of a lower temperature?
    But again it was take together at a spilt second so...uhm..
    Hi dotaboy, do u mean u have exactly same experience? photos taking almost same time but different color tone?grey and blue? =)

  9. #9

    Default Re: exposure question on olympus XA

    thanks littlewolf for explanation.. it reminds me to get clue on negatives itself, i did the scan from the lab, however i don't have a scanner or i can just verify it by re-scan.

    it could be the lab technician or the lab scanner do a color correction on it..

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    Default Re: exposure question on olympus XA

    Quote Originally Posted by LENS View Post
    thowever i don't have a scanner or i can just verify it by re-scan.
    If there are drastic differences, you should be able to see them on the negatives with the naked eye.

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