Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 68,692   Posts: 1,482,406   Online: 696
      
Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 32
  1. #21
    keithwms's Avatar
    Join Date
    Oct 2006
    Location
    Charlottesville, Virginia
    Shooter
    Multi Format
    Posts
    6,079
    Blog Entries
    20
    Images
    129
    Yes, pentaxuser, 1 stop means a factor two in time or one click on the old 2.8-4-5.6-8-16-22 aperture scale.

    5 stops filter factor means that your exposure time will be 2x2x2x2x2 = 2^5 = 32 times longer (assuming that you hold the aperture constant).

    I have a very simple procedure for shooting with IR filters that has served me well. First of all I do NOT make any adjustments in the ISO, I've never been comfortable with the thought of filters changing my ISO! All the filter does is affect how much exposure I need to give the film, plain and simple. So I meter the scene, and make up the desired filter factor by opening up apertures and/or lengthening the exposure. That's all. Takes about two seconds and there is zero math nor memorization.
    "Only dead fish follow the stream"

    [APUG Portfolio] [APUG Blog] [Website]

  2. #22
    2F/2F's Avatar
    Join Date
    Apr 2008
    Location
    Los Angeles, CA
    Shooter
    Multi Format
    Posts
    8,008
    Images
    4
    Quote Originally Posted by keithwms View Post
    Yes, pentaxuser, 1 stop means a factor two in time or one click on the old 2.8-4-5.6-8-16-22 aperture scale.

    5 stops filter factor means that your exposure time will be 2x2x2x2x2 = 2^5 = 32 times longer (assuming that you hold the aperture constant).

    I have a very simple procedure for shooting with IR filters that has served me well. First of all I do NOT make any adjustments in the ISO, I've never been comfortable with the thought of filters changing my ISO! All the filter does is affect how much exposure I need to give the film, plain and simple. So I meter the scene, and make up the desired filter factor by opening up apertures and/or lengthening the exposure. That's all. Takes about two seconds and there is zero math nor memorization.
    Nobody is saying they change your ISO. That is impossible, as the characteristics of each film are set at manufacture. What the filters do change is the EI. BY doing so, all you are doing is applying an across-the-board exposure compensation, which makes your meter directly readable. If you are going to make every single shot on a roll with the same filter factor, using a different EI makes direct reading possible, and makes things more quick (and mistakes less likely). No matter what EI you use, the ISO remains the same. Nothing can change the ISO except...well, the ISO!
    Last edited by 2F/2F; 06-16-2009 at 03:56 PM. Click to view previous post history.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

    - Rob Tyner (1944 - 1991)

  3. #23
    keithwms's Avatar
    Join Date
    Oct 2006
    Location
    Charlottesville, Virginia
    Shooter
    Multi Format
    Posts
    6,079
    Blog Entries
    20
    Images
    129
    Well, look around and you will see people saying that such and such film should be rated at some nonstandard ISO when using filter such and such. ISO is ISO of course, the "S" is for "standards" and what they really mean is E.I. But actually... I also do not care to speak of filter factors in terms of E.I. because for me, E.I. is something I will use in development, i.e. to deal with CI issues, not to compensate for a filter. I switch filters quickly and also go back and forth between different backs with films that will be developed differently, so... my method allows me to keep it all clear and simple.

    Wait! Yes, I do realize that there are at least two ways to skin a cat, but... I much prefer thinking about filter factors in terms of stops. That's just me, people can (and will) do whatever they want
    "Only dead fish follow the stream"

    [APUG Portfolio] [APUG Blog] [Website]

  4. #24
    stradibarrius's Avatar
    Join Date
    Jan 2009
    Location
    Monroe, GA
    Shooter
    Medium Format
    Posts
    1,382
    Images
    163
    Keith thanks for the description of how you set up for your IR shots. I had read somewhere about changing the ISO setting in the camera as a method to adjust for the "filter factor" That confused me a bit and I even started a thread basically asking the question about adjust my ISO for the filter factor.
    The way you make your adjustments makes logical sense to me and seemed to be the simplest way.
    "Generalizations are made because they are generally true"
    Flicker http://www.flickr.com/photos/stradibarrius
    website: http://www.dudleyviolins.com
    Barry
    Monroe, GA

  5. #25

    Join Date
    Apr 2004
    Location
    Montgomery, Il/USA
    Shooter
    Multi Format
    Posts
    4,822
    IF and only IF you're using a handheld meter you may modify your ISO by changing the ASA dial.
    Because it's not looking through the filter, it can't "see" the factor.
    Also, an in-camera meter doesn't see with the same spectral response as the film it is possible for an incorrect exposure reading. Like EI you need to test for your own filter factor for each filter.
    Heavily sedated for your protection.

  6. #26
    naaldvoerder's Avatar
    Join Date
    Apr 2004
    Shooter
    35mm
    Posts
    578
    Images
    26
    Is this helpfull in any way?????

    http://www.eazypix.de/ir/filter/filter.html

  7. #27
    MattKing's Avatar
    Join Date
    Apr 2005
    Location
    Delta, British Columbia, Canada
    Shooter
    Multi Format
    Posts
    11,578
    Images
    59
    Quote Originally Posted by naaldvoerder View Post
    Is this helpfull in any way?????

    http://www.eazypix.de/ir/filter/filter.html
    Thanks - I've bookmarked it!

    Matt

  8. #28
    thefizz's Avatar
    Join Date
    Dec 2004
    Location
    Trim, Ireland.
    Shooter
    Medium Format
    Posts
    2,013
    Images
    37
    Quote Originally Posted by keithwms View Post
    I have a very simple procedure for shooting with IR filters that has served me well. First of all I do NOT make any adjustments in the ISO, I've never been comfortable with the thought of filters changing my ISO! All the filter does is affect how much exposure I need to give the film, plain and simple. So I meter the scene, and make up the desired filter factor by opening up apertures and/or lengthening the exposure. That's all. Takes about two seconds and there is zero math nor memorization.
    I'm with Keith on this, always seemed the simplest way to do it, especially if using different filters as I do.

    Peter
    www.thephotoshop.ie
    www.monochromemeath.com

    "you get your mouth off of my finger" Les McLean

  9. #29
    GJA
    GJA is offline
    GJA's Avatar
    Join Date
    Jun 2009
    Location
    New Hampshire
    Shooter
    4x5 Format
    Posts
    112
    I also have a question.

    I see that freestyle offers two Lee filters, one an 87 and one an 87C. They specify that the 87 lets in light above 740nm and the 87C lets in light above 775nm. Are these for different films? If so, which is for which films.

  10. #30
    keithwms's Avatar
    Join Date
    Oct 2006
    Location
    Charlottesville, Virginia
    Shooter
    Multi Format
    Posts
    6,079
    Blog Entries
    20
    Images
    129
    I think the 87C will be too high a cutoff for most of the films on the market. I use the 87 and it's already +10-14 stops, depending.

    So, unless you plan to do digital IR or have HIE in the fridge, skip the 87C.
    "Only dead fish follow the stream"

    [APUG Portfolio] [APUG Blog] [Website]

Page 3 of 4 FirstFirst 1234 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin