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  1. #31
    Patrick Robert James's Avatar
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    I have a bunch of meters: a drawer full. At one point I thought it would be fun to collect them. A Weston IV is in the mix, which I don't really use much truth be told. Every now and then I take them all out and compare them to make sure they still work. The Weston is still right on the money compared with two Gossens. I also have an old Zeiss Ikophot which is neat though not sensitive enough in low light. Sometimes it is just fun to use the old stuff. When the old meters stop working, I throw them out. I should really use the Weston more. It is a heck of a lot smaller than the Gossen SBC I prefer.

    In the end, the best meter is always your brain, just saying...

  2. #32
    Steve Smith's Avatar
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    I also have an Ikophot. It surprises me as it is accurate enough to use with transparency film.


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  3. #33
    Bill Burk's Avatar
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    Steve Smith said 400 = Sunny 16, that's off by 1/3 stop.
    Close enough to use Steve's rule of thumb in a pinch.

    Steve's rule gives you 1/3 stop more exposure.

    Here is how I would use the rule of thumb:

    I typically take 1/3 stop off box speed when I select my EI.

    I could use Box Speed with Steve's Sunny 16 = 400 equivalent.
    ---

    Found this thread which correlates Weston Speed to ASA...

    Two of the links are dead. One of the links works, but shows a chart comparing OLD ASA to Weston.

    http://www.apug.org/forums/forum48/1...eston-asa.html

    For my own convenience, I converted to New ASA, maybe this will help.


    DIN - New ASA - Weston
    9 - 6 - 4
    10 - 8 - 5
    11 - 10 - 6
    12 - 12 - 8
    13 - 16 - 10
    14 - 20 - 12
    15 - 25 - 16
    16 - 32 - 20
    17 - 40 - 25
    18 - 50 - 32
    19 - 64 - 40
    20 - 80 - 50
    21 - 100 - 64
    22 - 125 - 80
    23 - 160 - 100
    24 - 200 - 125
    25 - 250 - 160
    26 - 320 - 200
    27 - 400 - 250
    28 - 500 - 320

  4. #34
    Steve Smith's Avatar
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    I always thought Weston was 0.8 of ISO (ASA) So Weston 80 for ISO 100.

    Set the meter to Weston 80 and at 400 it gives f16 at 1/125

    So what is this 'new ASA'? And is it the reason why the ASA settings do not quite correspond with the DIN settings on my Ikophot meter?

    EDIT: Actually, it's further out than that. If I set it to DIN 21 it reads ASA 40 on the other side.


    Steve.
    Last edited by Steve Smith; 03-23-2013 at 12:24 PM. Click to view previous post history.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  5. #35
    Mainecoonmaniac's Avatar
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    Being Merican' is the Weston rating the Metric version of ASA?
    "Photography, like surfing, is an infinite process, a constantly evolving exploration of life."
    Aaron Chang

  6. #36
    Steve Smith's Avatar
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    It's similar in that the numbers double or halve for each stop of sensitivity but the base number is different.

    I always thought Weston 80 was equal to ISO/ASA 100 but Bill's post above casts some doubt on it.


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  7. #37
    Bill Burk's Avatar
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    My post isn't completely well researched... I'd be happy to fix it if someone points out a mistake in my table.

  8. #38
    Steve Smith's Avatar
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    I can't say if there is a mistake in your table, but what I usually use is here: http://www.jollinger.com/photo/meter...eed_table.html

    (towards the botton of the page).

    And also on page three of Weston's manual: http://jameskbeard.com/Photography/W...on_Ratings.pdf

    And here: http://www.westonmeter.org.uk/speeds.htm it is also Weston 80 = ISO 100.

    It also states this:
    Up to the Master IV the scale on the dial is in cd/ft2 - foot candles, now known as Lumens. After the IV, Weston started to use arbitrary numbers. With the baffle open, the scale is from 0.2 to 50 and with the baffle closed, 25 - 1600. Note the overlap - it's usually best to use the baffle-open in this overlapping area as the meter is more accurate there.
    So it should be possible to work out what 400 lumens (cd/ft2) relates to.


    Steve.
    Last edited by Steve Smith; 03-23-2013 at 01:51 PM. Click to view previous post history.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  9. #39
    Bill Burk's Avatar
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    The Jollinger table is suspect, different Weston speeds for same DIN between Europe and US?

    Well I like the logic Chan Tran wrote in the first post of this thread:

    http://www.apug.org/forums/forum48/7...master-ii.html

    He wrote: "For example, 400 c/ft^2 which is EV15 for ISO100 but dial this value in the built in dial I would get 1/130@f/20 which is EV15 and 2/3. Using Weston rated speed of 80 for ISO100 I would get 1/130@f/18 which is EV15 and 1/3.
    It seems to get the correct exposure setting I would have to set the dial for ... 64 instead."

    And I wouldn't mind clarification on the EV number for 400 c/ft^2 - I kind of remember from the enlarger-sensitometer thread it's not precisely 15...

  10. #40
    Steve Smith's Avatar
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    O.K... I'll do it.

    On Wikipedia there is a table of EV at ISO 100 settings to lumens. It gives EV 15 as 4096 cd/m2. Converting from metres to feet gives me 381 cd/ft2.

    Very close to my 400 figure (about 95% of it).


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

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