Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,822   Posts: 1,581,886   Online: 1162
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 12
  1. #1
    metod's Avatar
    Join Date
    Mar 2006
    Location
    Montreal
    Shooter
    Multi Format
    Posts
    102
    Images
    10

    Infrared-how to adjust zoom with no markings?

    I generally use my old Canon AE1 with 50 and 28 mm lenses for infrared film. I’d like experiment a bit with a longer zoom, which I have only on my Canon Rebel. Of course, the zoom does not have any infrared markings on it. Is there a rule of thumb for adjusting the focus when using longer lens (say 100-300 range) for infrared shooting?

    Thanks.

  2. #2
    kb244's Avatar
    Join Date
    Dec 2005
    Location
    Grand Rapids, Mi
    Shooter
    Multi Format
    Posts
    818
    Images
    63
    Generally the longer the zoom, the more you have to shift (so if its 10 foot and you have to shift to 8 to be right on a 50mm, you'll probally have to shift it to 6 or 5 on a 200mm ).

    I don't know of any exact science to how to actually figure out the real distance, I just know on my Tamron 70-210 for my Canon FD, 70 was just a nudge shift, where as 210 was more dramatic.
    -Karl Blessing
    Karl Blessing.com
    The Bokeh
    Color Film always existed. It's just the world was always black and white till recently.

  3. #3
    colrehogan's Avatar
    Join Date
    May 2004
    Location
    St. Louis, MO
    Shooter
    Large Format Pan
    Posts
    2,016
    Blog Entries
    3
    Images
    16
    Does your Canon rebel use an IR sensor to count the sprockets between frames? What IR film were you planning to use/do you use?
    Diane

    Halak 41

  4. #4
    kb244's Avatar
    Join Date
    Dec 2005
    Location
    Grand Rapids, Mi
    Shooter
    Multi Format
    Posts
    818
    Images
    63
    Quote Originally Posted by colrehogan
    Does your Canon rebel use an IR sensor to count the sprockets between frames? What IR film were you planning to use/do you use?
    Even if it does, might not be a big problem as noted by one of my writers.
    IR in a Canon A2
    -Karl Blessing
    Karl Blessing.com
    The Bokeh
    Color Film always existed. It's just the world was always black and white till recently.

  5. #5

    Join Date
    Jan 2006
    Shooter
    Multi Format
    Posts
    1,730
    Get a Sony or similar camcorder that has "night vision". Confirm that the camera sees IR by pointing it at a remote control for a TV and pushing some button; you should see the LED remote flash through the viewfinder.

    Place the remote behind some hard-edged object at a given distance and tape one of the buttons down to pulse continuously. Paint the object with the IR light.

    Place the slr on a tripod at the given distance to the film plane you wish to check. Load dummy load, open back, open shutter on "T" with cable release. Turn out all lights and look at film plane through base using the Camcorder and night vision. Focus image painted in IR on film emulsion. Turn on light and compare difference between what you have in IR and what works in visual spectrum. Try a variety of distances to try to get a feeling for what offset works.

    Frank

  6. #6
    Ole
    Ole is offline
    Ole's Avatar
    Join Date
    Sep 2002
    Location
    Bergen, Norway
    Shooter
    Large Format
    Posts
    9,282
    Blog Entries
    1
    Images
    31
    The IR markings are for far IR - the kind only Kodak HIE is sensitive to. With any other film (and HIE with most filters, too) it can safely be ignored.

    If there is significant focus difference between visible light and near IR, that lens is so badly colour corrected it will be unable to take a sharp picture with any film.
    -- Ole Tjugen, Luddite Elitist
    Norway

  7. #7
    metod's Avatar
    Join Date
    Mar 2006
    Location
    Montreal
    Shooter
    Multi Format
    Posts
    102
    Images
    10
    Thanks guys. Rebel IIS is one of the older generations of EOS and use mechanical sprockets for frame counting. That is at least what I've read on the web. I'll give it a try and bracket more than usual with the zoom and see how it goes.

    Metod

  8. #8
    TheFlyingCamera's Avatar
    Join Date
    May 2005
    Location
    Washington DC
    Shooter
    Large Format
    Posts
    8,509
    Blog Entries
    51
    Images
    437
    The quick and dirty solution to avoid the problem is to shoot everything at F16 or smaller. That will cover your DOF sufficiently that even if your focus is off a bit you'll still be in the DOF of the aperture.

  9. #9
    colrehogan's Avatar
    Join Date
    May 2004
    Location
    St. Louis, MO
    Shooter
    Large Format Pan
    Posts
    2,016
    Blog Entries
    3
    Images
    16
    May I suggest browsing this site for further tips on using Kodak HIE:

    http://mysite.wanadoo-members.co.uk/...ght/index.html
    Diane

    Halak 41

  10. #10
    Sean's Avatar
    Join Date
    Aug 2002
    Location
    New Zealand
    Shooter
    Multi Format
    Posts
    8,591
    Blog Entries
    7
    Images
    15
    I heard a while back that Apochromatic lenses do not need IR adjustments, is this true? If so you might be able to find a apochromatic zoom lens..

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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