SJ8 EV-Value

Discussion in 'SJ8 Series' started by Julian Pink, Sep 17, 2018.

  1. Julian Pink

    Julian Pink New Member

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    Hi guys!
    Does anybody know what the EV-Value sets in the SJ8? I mean does it physically changes something or is it just a software-based brightness correction?
    In the manual is written, that the EV-Value influences the time at which images are taken, but in SJ8 shutter-time can be adjusted seperately. Or does it pick a higher ISO when I set higher EV-Value at fixed shutter time?
     
  2. Sulev Svilponis

    Sulev Svilponis Elite

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    EV is Exposure Value. It depends on 3 components: ISO, aperture and shutter speed. As the aperture for this camera is fixed, only the ISO and the shutter speed are adjustable.
    +1 EV = 2 times larger ISO value or 2 times longer Exposure time or combination of these 2 parameters so, that the total effect on exposure is 2 times more light.
    -1 EV = 2 times smaller ISO value or 2 times shorter Exposure time or combination of these 2 parameters so, that the total effect on exposure is 2 times less light.

    I suppose, that if you fix the Shutter speed and adjust the EV, then the ISO value would be selected accordingly. I don't have SJ8 yet, so can't tell you, if the camera overrides one or both of your settings, if you fix both the ISO and the Shutter speed and shift the EV value. You may test it by yourself. But one thing is for sure, nothing changes physically if you set EV correction.
     
    Last edited: Sep 17, 2018
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  3. Julian Pink

    Julian Pink New Member

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    Thanks for the detailed explanation!

    When you set the shutter speed with the SJ8 then the ISO is set automatically to "auto" and vice versa. So you can adjust just one of them. I guess that means that EV-Value influences the variable parameter.
     
  4. SiB77

    SiB77 Member

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    Shutter speed can not be manually adjusted. All movement is blurry. I wish there was sport setting for short shutter speed.
     
  5. Julian Pink

    Julian Pink New Member

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    Shutter speed is just in the photo and photo lapse mode available.

    I guess the movements are blurry in video, because of low light conditions. Maybe if you take a higher EV-Value in Video mode it sets a higher ISO and can therefore use an higher shutter speed. But I have not tested this yet.
     
  6. Sulev Svilponis

    Sulev Svilponis Elite

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    In the darkness negative EV value should usually applied. EV correction is not meant for turning darkness into daylight! It is meant for correcting EV so, that it corresponds to the actual conditions. The "wisdom" of cameras usually tries to use average expose value for every scene, causing bright scenes to appear darker and dark scenes to be brighter than actual luminocity was. If it's too dark, causing blurring of the video frames, then positive EV adjustment can't help! Only negative EV correction might help, causing darker video, hence if the ISO is fixed, faster shutter speeds.
     
    Last edited: Sep 17, 2018
  7. SiB77

    SiB77 Member

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    Absolutely opposite. In dark use positive EV and in bright light negative EV.
     
  8. Sulev Svilponis

    Sulev Svilponis Elite

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    That's why you have problems with your cameras, but not me!
    You just don't understand digital cameras and camcorders!

    Read this, for some EV basics:
    http://www.digital-photo-secrets.com/tip/19/exposure-value/
     
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  9. SiB77

    SiB77 Member

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    Ok. Enjoy your over exposed and dark images.
     
  10. Sulev Svilponis

    Sulev Svilponis Elite

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    You should not worry about my images! Get yours right first!
     
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  11. Julian Pink

    Julian Pink New Member

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    Today I made some testing with the SJ8.
    First I set ISO manually and shot two pics at different EVs. The result was that the shutter time changed - like expected.
    Then I set the shutter speed manually and made two pics with different EV-Values again. Surprisingly, in this case the ISO remained the same.
    So apparently the EV-Value just influences the shutter speed in the SJ8 (aperatur is fixed by design and ISO remains constant)

    If that theroy is right than maybe in video mode the EV-value directly influences shutter speed too.
     
  12. Sulev Svilponis

    Sulev Svilponis Elite

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    Excuse my poor English, but I do not understand, if the shutter speed changed in your second test, regardless that you set it manually? Or was there any changes alt all, when you compared those two photos? You must pay attention, that if the depending parameter (in the second test - the ISO) is already stuck in it's limits, then EV correction can't change anything. It does not extend magically supported ISO or shutter speed range. If depending parameter has already reached it's limit, then EV can't push it any further.
     
    Last edited: Sep 18, 2018
  13. Julian Pink

    Julian Pink New Member

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    At the second test I fixed the shutter speed to 2 seconds. After that the ISO was set to "auto" automatically by the cam. Then I made two pics with this settings but different EVs. One with EV=0 and one with EV=+2.
    The result were two exact same images with ISO800.
     
  14. Sulev Svilponis

    Sulev Svilponis Elite

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    Ok, I got now, what you did.
    I suppose then, that the ISO:Auto is limited with ISO800, and don't go any further from there (remaining 3 supported ISO stops are off limits for programmed Exposure settings and are selectable only by user).
    If this kind of situation happens at testing, then just leave the shutter speed as it was set, but apply EV correction with opposite sign. This will reveal, if this EV correction will change the ISO or not.
     
    Last edited: Sep 18, 2018
  15. Julian Pink

    Julian Pink New Member

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    Good
    Good idea! I will test this soon. Yesterday I had no time for detailed testing..
     
  16. Julian Pink

    Julian Pink New Member

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    After a little bit testing, I can confirm that ISO800 is a maximum limit, when making photos at fixed shutter time of 2" (and ISO: auto).
    Interestingly, when I shoot with shutter time 1/500 the ISO limit goes up to ISO1600.
    It does not matter for the ISO limit, if the photo is over-, or underexposed.

    When there are no ISO-limits nearby, then everything works like expected -> different EV-Values at fixed shutter time, directly influence the picked ISO.
     

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