Getting balance across the tonal range -strobe flash and the 11x14

Discussion in 'Lighting' started by David, Oct 2, 2005.

  1. David

    David Member

    Messages:
    309
    Joined:
    Sep 10, 2002
    Location:
    Melbourne, V
    Shooter:
    ULarge Format
    I'm doing some flash work with an 11x14 and using Efke PL100. The main strobe is a soft-boxed Hensel 3200 and the fill is a gridded 1500 monoblock. I'm taking a synched reading with a Sekonic L508 and exposing as shown with exceptions for bellows extension, etc. The skin tones are coming out great as are most tones, but the dark tones, like black clothing are coming out seriously underexposed. The only solution I know is to throw more light at these areas but then the skin tones would blow out.

    I'm very new to strobe lights, don't really like them but require them for this project. Are there ways to gain density on the low tones without blowing out the mid and high tones? Thanks for your suggestions.
     
  2. Donald Miller

    Donald Miller Member

    Messages:
    6,242
    Joined:
    Dec 21, 2002
    Shooter:
    Large Format
    Are you taking a reflected or incident flash meter reading? If incident, I would suggest switching to reflected readings of both shadows and highlights and balance your lights on that basis. I gather that you are making your exposure judgements on the basis of light values rather then dark values. Exposure is still going to be based on the dark values. It sounds to me that you need to increase exposure (either through amount of light, positioning of light, or of lens shutter speed) and this may require a decrease in development.

    Leaf shutters will synch at any shutter speed. You could increase exposure of the dark areas by choosing a longer shutter speed.
     
  3. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Messages:
    17,978
    Joined:
    Sep 7, 2002
    Location:
    Honolulu, Ha
    Shooter:
    Large Format
    This is not a function of format.

    Do you shoot PL100 in another format? You may just be overdeveloping, if you can't get the detail in the blacks and keep the highlights under control at the same time.

    If you've got your exposure index and development time for PL100 under control, I would reduce the contrast ratio in general--either reduce the main light or increase the fill. Take an incident reading of each light separately. If the scene has a wide reflectance range (pale skin in a black velvet dress, say), I'd probably set the main one stop over the fill, or maybe one and a half stops for a more dramatic look.

    Increasing the exposure time would produce an effect similar to increasing the fill, if the fill is fairly flat, and the ambient lighting isn't too unusual. In this situation, I'd prefer to increase the fill without changing the shutter speed, since it is usually easier to control the fill, and for ambient to match the main light, you may need to increase exposure time more than is desirable to produce the effect you want.
     
  4. David

    David Member

    Messages:
    309
    Joined:
    Sep 10, 2002
    Location:
    Melbourne, V
    Shooter:
    ULarge Format
    Thanks for the replies. I'm taking incident light readings. I would normally spot meter the salient shadows and expose from there, but with flash that's not possible - is it? I was running the fill light about 2 stops less than the main thinking that less would be too flat. I've experimented with the rations but am very new to strobe lighting. I will try to increase exposure time but that is pretty limited with people pictures. I'm also looking for more light as depth of field is such an issue here. Any bellows extension and you're an effective f22 before you can blink and that ain't much. I will experiment with less development. Have any of you used JandC 400 with strobes - I was thinking this might be a way to get more light as it were.
     
  5. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Messages:
    17,978
    Joined:
    Sep 7, 2002
    Location:
    Honolulu, Ha
    Shooter:
    Large Format
    That's your problem. A lighting ratio of 1:4 is very strong--what you might use, say, if you wanted half of someone's face to be lit normally and half almost in silhouette. For portraits and figure studies, a range of 1:2 or 1:3 would be much more common. I'd fix this before changing your development or exposure time.

    For studio portraiture with artificial lighting, unless you are after a special effect, you should always be processing your film for normal contrast and controlling contrast with the light. I don't usually spot meter in this situation, but there are spotmeters, like the Minolta Spotmeter F, that can do flash.

    J&C 400 looks fine with strobes, and it gets you more speed, if you want a smaller aperture.

    I like short DOF myself.

    There are a few tricks to keeping the subject in focus. The easiest is to tie a string to the tripod and put a knot where it meets the subjects nose. Have them hold the string to their nose while you focus on their eyes, then you can insert the filmholder, pull the darkslide, and check the focus with the string before making the exposure. I just shot some very close portraits on 8x10" (magnification about 1:1) with a 360/4.5 Heliar wide open using window light. Didn't use the string for the first two shots--both out of focus. Realized I needed the string, and the next four were all right on.

    Another method I've used is to pay very close attention to the nose shadow when focusing the shot seeing where it ends on the subjects lip, and then check it again before making the exposure. If the subject moves, the shadow will change, and if you remember where it is, you can adjust the subject's head slightly to get it back, and the subject will usually be in focus.