ISO/ Aperture/ Shutter query

Discussion in 'Photography Forums' started by johndow, Jan 17, 2008.

  1. johndow

    johndow
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    I have a panasonic FZ7 and thanks to its image stabilization i can shoot still subjects handheld at anything up to 1/6 seconds. I know all manufacturers vary in their IS systems, but i always assumed that 1/5 IS equated to 1/30 non IS. Is this correct??

    Also, i can't really take any pictures at greater than ISO100 due to high noise levels. I am hoping to trade up to a DSLR, but i want to know is their a standard relationship between ISO and Shutter for all cameras. I.e. at say f5.6 is the shutter speed at ISO400 4X quicker than the shutter speed at ISO100.

    I think if i could take photos on a DSLR at ISO400, they would have the same or less noise as my camera at ISO100 (shouldn't be difficult), and the faster shutter speed should cancel out the use of IS on the FZ7. ALthough at its widest, i can get an aperture of 2.8 opposed to most kit lense 3.6.

    Thanks in advance

    JD
     
  2. Peakoverload

    Peakoverload
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    The difference between whole apertures e.g. f/2.8 - f/4, whole ISO's e.g. 100 - 200 and whole shutter speeds e.g. 1/125th - 1/250th is always 1 stop of light regardless of the camera, sensor size, lens used, format etc etc etc

    Some cameras offer 1/2 or 1/3rd stop increments in ISO and shutter speed but these are still relative so in other words they would let in 1/2 or 1/3rd of a stop of extra light.

    As for your IS question, as you say it depends on the manufacturer and version of IS that is being used. It's not really fair/correct to say that 1/5 IS equats to 1/30 non IS as this doesnt take into account the effect shutter speed has on motion blur i.e. IS can remove/reduce camera shake but it can't stop a fast moving subject appearing as a blur when using a slow shutter speed. This is why IS is usually 'measured' in stops of light. Depending on the manufacturer IS can be the saving of anywhere between 2 and 4 stops of light which equates to 2 - 4 whole apertures or shutter speeds.

    HTH
     
  3. Yandros

    Yandros
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    Yes, the ISO/aperture/shutter relationship holds for all cameras.

    The current crop of DSLRs are absolutely useable at 400 ISO (probably not as clean as 100 ISO on most compacts though...(maybe equal to the noisy panny sensor though!). 800 ISO introduces a bit of grain, but it's not too bad.

    Don't forget that there are lots of IS options with DLSRs as well - Sony, Olympus and Pentax/Samsung in-body, and Canon/Nikon in-lens. Image stablised 1/8th second handheld 800 ISO, f3.5 on a DSLR means you can shoot in candlelight. f2.8 or better gives you more potential for shooting moving subjects in low light of course.
     
  4. Pirate!!

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    I have an older FZ3 as my backup. I generally have it set to ISO 80 and the OIS at MODE 2. TIFF or at times JPEG fine format. Try using A MODE. OIS works best when you need a slower shutter speed for hand held shots. For faster shutter speeds it's not really needed.

    I would be inclined to hang onto your FZ7 and just get a DSLR if you are going down that road.

    You know the Sony A100 kit is being offered by Argos for not a lot I suppose? Bargain!
     

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