Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 69,721   Posts: 1,514,953   Online: 1105
      
Page 2 of 2 FirstFirst 12
Results 11 to 16 of 16
  1. #11

    Join Date
    Feb 2009
    Location
    Oz
    Shooter
    Multi Format
    Posts
    481
    Quote Originally Posted by Palantiri7 View Post
    Thanks SW. I clearly don't understand! I know my Rollei 6003 meter used to overexpose blues slightly and underexpose reds so I don't know if that's the same thing here. Out of all the posts I've read about the Pentax (a lot!) I've never read anyone making mention of oddities in the meter's readings w.r.t. colour.
    This whole lightmeter thing is far more complex than would at first appear.

    I am no expert, but from what I've read, it seems that many lightmeters respond differentially to different wavelengths.

    For example, some cells (e.g., Selenium) over-respond to infrared "light" (i.e., heat), so, in low light conditions including a hot object (e.g. sun baked masonry), the reading would be inflated by the heat coming from the background (suggesting a "mid-gray object in bright light" situation) giving an underexposure of the nominal subject. So, the extra red end sensitivity could also result in underexposing red subjects, e.g. roses?

    At the same time, the concomitant lack of sensitivity to blue, would result in an overexposure of blue subject matter (remembering that the meter tries to render what it "sees" as middle-gray, so it registers the blue object as being a "mid-gray object in a low light" situation and indicates a greater exposure setting to make up for it).

    It's all a bit disconcerting, really, to those of us seeking some certainty in life.

  2. #12

    Join Date
    Jul 2007
    Location
    Netherlands
    Shooter
    Medium Format
    Posts
    5,686
    We have (still) two different thingies running in this thread,

    First is the colour sensitivity of the 'sensors' used in meters. Get a blue filtered silicon cell, and no more worries.

    The second is not to do with the colour sensitivity of filters, but is about the fact that different colours represent different tones. Differently coloured objects will reflect different amounts of light, even when all other properties, besides colour, of the material they are made of are the same. Meters will register different amounts of light coming from differently coloured objects, even when they have an absolutely flat spectral response curve.
    And that's what the Pentax manual is on about.

  3. #13

    Join Date
    Jan 2005
    Location
    Downers Grove Illinois
    Posts
    1,047
    Of course I do. It is like any other reflective meter, the meter assumes middle grey target.

    If you don`t want to mess around, measure the brightest and darkest areas of subjectand expose in the middle.

    That or learn where common colors fall, like cross lit snow, +1.5 or 2, green spring grass= 0, tree bark is 0 depending, blue sky, really blue, not overcast thin blue, is +1.

    I copied the colors ofsets from the book, reduced and and copied, reduced and copied again, then pasted it on the top of the meter. Works fine.

  4. #14
    L Gebhardt's Avatar
    Join Date
    Jun 2003
    Location
    NH - Live Free or Die
    Shooter
    Large Format
    Posts
    1,673
    Blog Entries
    1
    Images
    18
    Print out a zone dial sticker. Ralph Lambrecht has one at http://www.darkroomagic.com/DarkroomMagic/Camera.html. There are others on the web, or you can make your own. Meter the highlights place around zone 7 to 8. Bracket a bit on the first shots and you should get a feel for the meter and Velvia.

  5. #15

    Join Date
    Jul 2007
    Location
    Netherlands
    Shooter
    Medium Format
    Posts
    5,686
    A zone dial (sticker), and a reminder of what can act as a reference and how, are not the same thing.

  6. #16
    Palantiri7's Avatar
    Join Date
    Jan 2006
    Shooter
    Large Format
    Posts
    127
    Thank you so much everybody! Yes, I printed out the zone sticker and installed it in place. I have done some initial tests using the Pentax exposure readings against my 5D Mk II just to get a ballpark idea about the meter's behaviour. This meter seems very accurate indeed. So far I haven't noticed any oddities w.r.t. different colours. It seems to expose consistently .5 stop over the 5D, which always tends to underexpose a bit. The 5D's meter is, however, far more sensitive in low light conditions. The Pentax seems to be about the same as the Gossen Starlite's (now defunct) spotmeter in terms of low light sensitivity, which is to say, not too great. Anyway, many thanks for the input. Q.G. has it down, thanks!

Page 2 of 2 FirstFirst 12


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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