meter shutter speeds dont match cameras shutter speed

Discussion in 'Exposure Discussion' started by Christopher Colley, Dec 3, 2005.

  1. Christopher Colley

    Christopher Colley Member

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    Hello!

    I have a situation which I am sure someone else figured out before, or at least found a way to make it more simple to shoot..

    I am not great at math or fractions...

    My light meters count shutter speeds, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2.. 1sec...

    But the shutter on my camera is 1/400, 1/200, 1/100, 1/50, 1/25, 1/10, 1/5, 1/2, 1sec..

    How would I easily overcome this barrior without buying a new shutter, or a new meter?

    I find myself having to shoot at 1/2 and 1 second nearly all of the time because its the only pair that matches the meter and shutter..

    any suggestions would be useful!
     
  2. Donald Miller

    Donald Miller Member

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    The speeds on your shutter are near enough to the more commonly used speeds.

    ie...1/400 would work for 1/500, 1/50 would be used instead of 1/60, and 1/5 would work for 1/4...
     
  3. Christopher Colley

    Christopher Colley Member

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    so, as long as I keep consistant, I shouldnt have any negative results or suprises?
     
  4. Dave Parker

    Dave Parker Inactive

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    Christopher,

    I have shot for a number of years now with the same type of readings and never had a problem, this is actually pretty common, how old is the meter and shutter, depending on the film your shooting, but again, most of the time, as Donald said, if the meter indicates 1/500, shooting at 1/400 is not a problem..

    Dave
     
  5. Dan Fromm

    Dan Fromm Member

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    Set the shutter speed closest to what the meter recommends at your desired aperture, then set the aperture the meter wants at that shutter speed. And Dave is right, close is usually good enough.
     
  6. Christopher Colley

    Christopher Colley Member

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    Thanks,

    I am using a Synchro-Compur shutter (I believe it is a 'model O', self timer with M/X switch) and a Sekonic L-428 for ambient and a built in center weighted meter in a 35mm camera for reflected readings.

    at the current time I am using 4x5 ilford HP5+, I would likely never use anything other than a 400iso sheet film, possibly using 50 or 100 in the future..
     
  7. Ole

    Ole Moderator Staff Member Moderator

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    I'm using the same shutters - Compur #0 MXV - and even older ones. There isn't really any problem with the speeds except around 1/20. The rest of the speeds are close enough as others have already said.

    Another question is what speed the shutter actually fires at, which can be up to 20% of and still be within specifications. Ther will also be a difference in the shutter speed with aperture, which would have to be compensated for if you wished to be very, very exact.
     
  8. voceumana

    voceumana Member

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    Back in the 1950's (I think) they changed the standard shutter speed sequence from the one that ends at 1/400 to the one that ends at 1/500. The older sequence wasn't quite on a factor of 2 change between each speed and the new one is.

    No problem: just use the closest marking. Mechanical controlled shutter speeds are not at all accurate, so any attempt to compensate for the difference between the old & new scale may introduce more error than it fixes unless your shutter is tested and determined accurate.

    But if you are inclined to correct for the differences, then these are the corrections:

    1/5, open 1/3 stop from the 1/4 reading
    1/10, open 1/3 stop from the 1/8 reading
    1/10, close 2/3 stop from the 1/15 reading
    1/25, close 1/4 stop from the 1/30 reading
    1/50, close 1/4 stop from the 1/60 reading
    1/100, close 1/3 stop from the 1/125 reading
    1/200, close 1/3 stop from the 1/250 reading
    1/400, close 1/3 stop from the 1/500 reading

    As you can see, (with the exception of 1/15th on the new series) you are at most 1/3 stop away. Unless you are terribly accurate with your metering, this is negligible.

    The way to calculate the correction in stops is:

    log (new speed/old speed) divided by log 2,

    or (log base 2 of new speed/old speed).

    Charlie