How many watt seconds do I need?

Discussion in '35mm Cameras' started by me, Dec 9, 2004.

  1. me

    me Guest

    How many watt seconds do I need? I'm using a 35mm film camera. I'll be
    shooting in my single car basement/garage and a smallish living room.
    Ambient light from sun is dim, EV4 at 100 ISO for both.

    I'd like 3 lights, main, fill and hair/bg/kicker. I assume the main and fill
    should be the same w/s but how many w/s should the other light be? I'm
    trying to come up with a ratio like 1/2 or 1/4 as many w/s as main.

    I also want more than 3 power levels. I think this would be more versatile
    and may be a necessity since I don't have room to move lights further from
    the subject to reduce power. What do you think?

    I apologize if this question is vague but I have never purchased studio
    lights before.
    Thank you for your help.
    me, Dec 9, 2004
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  2. A really nice feature, perhaps more important than ws is can you
    independently adjust output to each of the heads. I have a 1200 ws
    Power pack but can't independently adjust the lights, other than to
    move them back or forward or use a louver inside the softbox.

    1200 is good and strong for 100 asa. More is better if you can afford
    Gregory Blank, Dec 9, 2004
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  3. me

    me Guest

    I should have said I'm more interested in monolights than power pack /
    heads. I just knew I'd leave something out!
    me, Dec 9, 2004
  4. me

    Alan Browne Guest

    If you're shooting static subjects then ambient lighting (plus flash) is not so
    important (but a tripod and cable release are).
    I'd suggest 1 800 and 2 400's if you can afford it. I shoot 2 200's and 1 40
    W-s for BG's and it is enough for most shooting at ISO 100 f/5.6 - f/11 with one
    or two lights theough a softbox or off an umbrella.

    You could probaly get 1 800, 1 400 and 1 ac strobe to start.

    You can get fairly low price, low power AC strobes for hair/rimlighting. They
    have no control but some creative use of white plastic sheets will pull the
    power down further. I took an old Sunpak (about 25 W-s) and mounted it to the
    bottom of a cardboard food can (cut a rectangle in the metal bottom and used the
    resulting metal flaps to elastic-band the flash to the can) and this made a
    lightweght snoot to put hairlights or background spots on the wall. Add a slave
    and boom... all set.
    Absolutely. Once you have a lighting setup in place, controlling the power
    output is essential and tuning by moving the lights is very tedious and affects
    the shape of the lighting effect. (I do this all too much, but new lights are
    not high on the priority list).
    Shooting with stuido lights is taking full control of the lighting. Your
    distrust of AUTO and TTL flash will go up 10 fold afterwards.

    I'd like to get AlienBees as they have a full 5 stop control range, modeling
    light slaved (or not) to the power level.

    Of course you will need an incident flash meter. The Minolta VF is not bad, the
    Minolta V is great. The Sekonic 508 is very good (and includes a spot meter).
    The meter should have a PC terminal (and it is handy if it has a non-cord mode
    as well).

    Alan Browne, Dec 9, 2004
  5. me

    teflon Guest

    At least a couple of 500's and a 250, depending on budget. A little more
    would be handy, but not essential - especially considering the amount of
    room you have. It may well cause difficulties if they are too powerful,
    though clipping on some ND gel would help.

    Take into account the cost of any soft boxes, grids/snoots, brollies, and
    barndoors you may need, as well as the flash meter already mentioned.
    teflon, Dec 9, 2004
  6. me

    Tony Guest

    Start with a book on studio lighting. To begin with your assumption that
    main and fill should be equal is wrong. However there is no reason you can't
    use lights of equal power simply set up to give you the ratio you want.
    A book will show you set-ups and power ratios so that you don't have to
    re-invent 100 years of lighting for yourself. There are a few lighting books
    on the following page.
    Tony, Dec 9, 2004
  7. me

    me Guest

    I was referring to rated power not the ratio of main to fill.
    Which of those books would tell me how many w/s to buy (taking into account
    the size of the rooms I list above)?
    Thank You,
    me, Dec 9, 2004
  8. me

    teflon Guest

    Take into account the cost of any soft boxes, grids/snoots, brollies, and
    ....I would also suggest a spare sync lead. They are notorious for going
    wrong, and the only time you'll ever find out is during a shoot.
    teflon, Dec 10, 2004
  9. For portraiture you don't need much more than 50-100 watts per light.
    Randall Ainsworth, Dec 10, 2004
  10. don't need to give 'em a sunburn. Shooting portraits of
    ordinary people at f/16 is not advised.
    Randall Ainsworth, Dec 10, 2004
  11. me

    Skip M Guest

    Remember the old quote, "Speed costs money, how fast do you want to go?"
    Substitute "Light" for "Speed' and "bright" for "fast."
    The lights I have only give me about 700w/s, but they've been sufficient for
    my purposes in the small space I have to work.
    Skip M, Dec 10, 2004
  12. me

    dadiOH Guest

    Watt seconds is not an accurate measurement of light output. Two
    different lights with the same ws rating could put out vastly different
    amounts of light.


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    dadiOH, Dec 10, 2004
  13. me

    me Guest

    What manufacturer's specification do you use when comparing?
    Thank You,
    me, Dec 10, 2004
  14. me

    Alan Browne Guest

    He wasn't asking about how much light, just a guideline on what he would need.
    As most monolights, and a good number of packlights allow you to control the
    power downwards, he just needs a reasonable top end. The various answers he got
    based on room size should be ample guidance.

    Alan Browne, Dec 10, 2004
  15. me

    Alan Browne Guest

    me wrote:

    You can only compare W-s. On the AlienBees site, they use to put up what
    aperture setting you would get at a fixed distance (10 ft.) for ISO 100 when
    using their basic reflector. (I don't recall if they gave a GN equivalence for
    this too). They've redone their website since then, so not sure if the same
    info is still there.

    Why don't strobe manufacturers give GN? Mainly becasue of reflectors and the
    behaviour of packed strobes with various cable lengths.

    For what you want to do a couple 400's and a 200 would be ample, a cut above (2
    x 800 + 1 x 400) would give you more manouevering room. But as I said an AC
    strobe or two is handy for touching up the lighting here and there.

    Alan Browne, Dec 10, 2004
  16. In a lot of the churches I photograph in, old & dimly lit
    Usually f/8 is barely possible with 100 asa for group shots, unless one
    is using full power. Additionally I print my own work which means I print
    people down so that the ambient light, on stained glass, candles etc.
    is part of the picture. Some people like shadows around the subjects
    heads (I don't).
    Gregory Blank, Dec 12, 2004
  17. Two lights on the pack can be adjusted but starts at 600 a piece, two
    stops down from full power is 150 ws per lamp I believe. I only need that
    much power on occasion for groups.
    Gregory Blank, Dec 12, 2004
  18. me

    Bandicoot Guest

    Bandicoot, Dec 12, 2004
  19. me

    Bandicoot Guest

    I was shooting in a church recently (the architecture, not a wedding, which
    I don't do) and needed 3000Ws to get f8 on some of the shots. But that was
    because for those shots I was filling daylight by bouncing the light from a
    single head from high up off a wall.

    Bandicoot, Dec 12, 2004
  20. me

    teflon Guest

    You advised that "infinite adjustability on every head" isn't needed - yet
    if lights were of widely different output, as you also advise, it would
    restrict flexibility. Surely cheap ND gels on a balanced set up is easier?

    ....oh, and there's nothing wrong with a 1:1 ratio.

    Let's not cripple the poor guy! ;]
    teflon, Dec 13, 2004
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