Quantaray Lens question

Discussion in 'Photography' started by Michael, Feb 28, 2004.

  1. Michael

    Michael Guest


    I have a Quantaray 70-300 lens. I can't get the focus ring to inifinity, but
    only to a symbol next to inifinity that looks like a little right-angle. I'm
    definitely having focus problems on long range targts - such as the moon....


    1) What does that symbol mean?
    2) Is it right that I can't get to the inifity symbol?

    Thanks in avance

    Michael, Feb 28, 2004
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  2. Sounds to me that what's not right is that you can't set the
    Moon to perfect focus...

    Normally, when I want to focus the Moon or the stars (or the
    Milky Way cloud), I have to turn it back a little bit from the
    top position (i.e., I move it all the way, then turn back
    maybe 3 or 5 degrees). Then the targets like the Moon are
    in perfect focus.

    Carlos Moreno, Feb 28, 2004
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  3. Michael

    Drifter Guest

    That little sideways "L" symbol represents where the infinity focus
    starts. With that lens you can actually focus "past infinity" (which
    is useless). In all likelyhood you are focusing too far past. Also
    that lens really suffers at anything below about f6.7

    I was given one of these lenses for $20 and I like the reach but it
    isn't a particularly good lens. Still as they say "any shot is better
    than no shot" and every once in a while I hit that combination that
    results in a very nice picture with that lens.

    "I've been here, I've been there..."
    Drifter, Feb 28, 2004
  4. Michael

    Mark P. Guest

    Focusing past infinity is not necessarily useless. IR focuses
    differently than visible, the degree of difference varying
    depending on the lens configuration. Therefore, often you
    have to focus a little further out when shooting with IR film.

    (actually, I may be wrong here, as the focus shift for IR may be
    in the other direction. I don't have a lens at hand to check)

    Mark P., Mar 1, 2004
  5. Michael

    Al Guest

    I think the IR mark is the other side. However, with long lenses, I
    understand that it may be necessary to focus beyond an indicated
    infinity as the temperature affects the focal length.
    Al, Mar 1, 2004
  6. Michael

    Drifter Guest

    Ah yes, I forgot about that. I stand corrected.

    "I've been here, I've been there..."
    Drifter, Mar 1, 2004
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