Tamron 90mm won't go to max aperture...

Discussion in 'Lens Lust' started by InLimbo87, Sep 20, 2008.

  1. InLimbo87

    InLimbo87

    452
    Jul 30, 2008
    Orlando, Fl
    Just bought a tamron 90mm f/2.8 off a user on here, and I'm having an issue with it. It'll only go down to f/3. Is this a common problem. What does it take to have it fixed?

    :frown:
     
  2. Phillip Ino

    Phillip Ino

    Nov 26, 2007
    Austin
    Don't fret, Ian. Nothing is wrong with the lens. I had a similar experience with my first macro lens. Depending on what you are focusing on, the macro part of the lens will not allow it to acquire max aperture. I forget the science behind it, but try to focus on something really far and see if you can get 2.8 :smile:
     
  3. InLimbo87

    InLimbo87

    452
    Jul 30, 2008
    Orlando, Fl
    Even when I have it manually set to focus at infinity it won't go below 3.0. I did notice the "variable aperture" aspect of macro, and that freaked me out at first too, lol...
     
  4. rotxlk82

    rotxlk82

    Jul 20, 2007
    UK
  5. InLimbo87

    InLimbo87

    452
    Jul 30, 2008
    Orlando, Fl
    Thanks for the link..

    Guess you missed my post because we posted at the same time, but the lens will not go under f/3.0 at any focus distance.
     
  6. gfx1

    gfx1

    75
    Mar 31, 2008
    the Netherlands
    It should go to f/2.8 between infinity and at 10 meters. Put camera at A and move the thumb-wheel a bit on your camera when it is focused at that distance.
     
  7. InLimbo87

    InLimbo87

    452
    Jul 30, 2008
    Orlando, Fl
    No, I just tried it again by focusing on my fiancee about 25 ft away from me, and could not get it below f3.0.
     
  8. rotxlk82

    rotxlk82

    Jul 20, 2007
    UK
    Hmm, that certainly doesn't sound right.
    Maybe there is a fault.

    I take it exposures are ok throughout the focus range
     
  9. Phillip Ino

    Phillip Ino

    Nov 26, 2007
    Austin
    Try switching it to "limit" instead of "full" and see if that works.
     
  10. InLimbo87

    InLimbo87

    452
    Jul 30, 2008
    Orlando, Fl
    Metering and exposures seem to be spot on. Limit/Full doesn't affect it...
     
  11. Isn't the issue here what I experience with some older chipped lenses -- that at "f/2.8" they communicate "f/3" to the body? Is this an older Tamron lens?

    This is supposedly "normal:"

    http://www.photodo.com/topic_21.html

    Did the seller experience this?
     
  12. rotxlk82

    rotxlk82

    Jul 20, 2007
    UK
    Bill's point may well be valid, if so it's not really much to worry about

    F3 and F2.8 are only 0.2 stops different anyway, so even if the F3 reading is true it's not like you're loosing oodles of light
     
  13. Phillip Ino

    Phillip Ino

    Nov 26, 2007
    Austin
    When you look at the shooting data on the LCD, what f stop does it say there? Can you post a picture with EXIF?
     
  14. InLimbo87

    InLimbo87

    452
    Jul 30, 2008
    Orlando, Fl
    f/3.0

    Test003.jpg

    The seller said that she hadn't tested it right before she sent it, but that she used to shoot with it almost exclusively at 2.8. I'm not too worried about the loss of light for the .2 difference, just wanted to make sure there wasn't anything majorly wrong. Just seems to be a fault.

    Thanks everyone for all your help.
     
  15. I agree -- I wouldn't worry about it and it's the same as my old Sigma (Quantaray) 24/2.8. Your EXIF reports what mine does -- MaxAperture of f/2.8 but actual aperture of f/3.

    I believe that it's actually still shooting at f/2.8, though. That is, the aperture is actually wide-open when the camera thinks it's at "f/3." The only negative in that case is that the autoexposure system will overexpose by that very small amount. Probably not really noticeable.

    I remember reading somewhere that sometimes these can be fixed if the manufacturers updates the chip in the lens. I don't know if Tamron has one available, or if it's even worth it.