Metering Shadows and filters

Discussion in 'B&W: Film, Paper, Chemistry' started by david b, Sep 18, 2004.

  1. david b

    david b Member

    Messages:
    4,031
    Joined:
    Oct 20, 2003
    Location:
    None of your
    Shooter:
    Medium Format
    I can't believe I am getting myself so confused but let me ask a question:

    If I meter a shadow with a spot meter, I am getting zone V. If I place an orange filter on the lens, this effectively brings the shadow down to zone III, right? So I should not make any adjustments, right?
     
  2. Deniz

    Deniz Member

    Messages:
    334
    Joined:
    Apr 12, 2004
    Location:
    Montreal,QC
    Shooter:
    Medium Format
    well depends on how much blue light there is in the shadow..
    experience will tell you that.
    thats why zone VI modifies the spotmeters so that you can read through the filter and get the right exposure..
    I hope somebody more experienced can help you better..

    good luck
     
  3. mobtown_4x5

    mobtown_4x5 Member

    Messages:
    244
    Joined:
    Feb 24, 2004
    Location:
    Baltimore
    Shooter:
    4x5 Format
    I can't meter through filters with my unmodified Pentax? Crap! I even have duplicate filters in it's size I do it all the time- what exactly is the issue?
     
  4. Tobik

    Tobik Member

    Messages:
    9
    Joined:
    Jul 9, 2004
    Location:
    Czech
    Shooter:
    Large Format
    It really depends on color of light illuminating shadows and on filter factor for this light.
    For instance I tested my red filter and its filter factor for red light is -1 stop, for blue light -4 stop and for white light -3 stop (general factor, the same is given by filter manufacturer). It means that under blue sky, shadows placed to zone III with only general filter factor in mind would fall lower - but not under sky with a lot of white clouds.
    The same happens with orange or yellow filter.
     
  5. Donald Miller

    Donald Miller Member

    Messages:
    6,242
    Joined:
    Dec 21, 2002
    Shooter:
    Large Format
    A contrast enhancing filter when used in conjunction with black and white materials will have the strongest effect on colors opposing it on a color wheel and it's weakest effect on it's same color.

    I have found that measuring the effect through the three color channels of a color transmission densitometer will give a fairly close indication of the amount of effect.
     
  6. gainer

    gainer Subscriber

    Messages:
    3,725
    Joined:
    Sep 20, 2002
    I think St. Ansel would say that the Zones are what you see, not necessarily what the meter sees. The deepest shadows in which YOU see detail are Zone II. If you choose to put them in the middle of your film's range, that's your business, but they really should be very close to the bottom of the film's range for best quality. David Vestal refuses to call that thing we use an "exposure meter". He calls it a "light meter" with a calculating scale. It does not see zones. It sees what you point it at, especially if it is a spot meter. If you have it set to calculate for Zone V, you should point it at what you see as Zone V. Then Zones II and up should be recorded on the film in a printable fashion, provided you develop properly. If you cannot visualize the zones when you look at a scene, then use a meter that allows incident light measurements. Believe it or not, a little experience with such a meter and "normal" development will help you to tune your visualization to what the meter "saw". Often, just a comparison of spot metering and incident metering can be helpful.

    As for filter factors, I think the same is true: try measuring with the filter in front of the meter and compare it with a measurement without the filter but adjusted by the filter factor. If the two measurements are in agreement, fine. Otherwise, spend an extra piece of film to find out which is better.
     
  7. ThomHarrop

    ThomHarrop Member

    Messages:
    172
    Joined:
    Dec 24, 2003
    Location:
    Denver, CO
    Shooter:
    4x5 Format
    Less confusing

    It might be less confusing if you take it one step at a time.

    1) Take the reading.
    2) Close down two stops to place it on Zone III.
    3) Adjust the exposure for your filter factor or actual light attenuation.

    It is a bit faster to try to do it all at once but I think it sometime leads to this kind of confusion.
     
  8. fhovie

    fhovie Subscriber

    Messages:
    1,247
    Joined:
    Mar 20, 2003
    Location:
    Port Hueneme
    Shooter:
    Large Format
    a couple of thoughts: It is said that nothing lives On Zone 3. I follow that rule. also, when shooting towards the sun, be careful of lens flare in the spot meter, you can wind up way off. Metering through a filter can be just as risky with flare.
     
  9. david b

    david b Member

    Messages:
    4,031
    Joined:
    Oct 20, 2003
    Location:
    None of your
    Shooter:
    Medium Format
    thomharrop,
    if i meter a shadow and it comes up f8@125, and i want it on zone III, it would be f8@500. but then i have to open the lens up 2 stops for the orange filter factor, which brings it back to f8@125. right? so why not just meter the shadow at zone v and let the filter do the rest?