focal plane location and filter size

Discussion in 'Digital Discussion & Q&A' started by malbec, Sep 29, 2009.

  1. malbec

    malbec TPF Noob!

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    please describe the symbols for focal plane location and filter size. what is the difference between the two?
     
  2. Flash Harry

    Flash Harry TPF Noob!

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    you don't get a "symbol" to describe where the focal plane is located, filter size(lens) on my nikons are on the base of the lens but sometimes on the ring. The focal plane is basically where your shutter is, the rear of, this is the point of focus of all lens made for the camera model you own. H
     
  3. musicaleCA

    musicaleCA TPF Noob!

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    Last edited: Sep 30, 2009
  4. Dwig

    Dwig TPF Noob!

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    Good definitions of what they define, but the don't relate to the OP's question

    The OP was not asking for definitions of the terms, but instead inquires as to what the symbols were.

    The focal plane in a camera is indicated, if indicated by a small circle with a line drawn through the center parallel to the focal plane. The line is usually about three times as long as the diameter of the circle.

    Filter diameters do not have any photographic specific symbol. You do often see the standard mathmatical symbol for "diameter" either preceding or following the number indicating the diameter in mm. This symbol is a circle with a diagonal line though its center. The line is rotated from vertical by about 30-45 degrees clockwise. The symbol is described about half way down this page:
    Diameter - Wikipedia, the free encyclopedia
     
  5. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    From what I've seen, the focal place symbol is a circle with a horizontal line through it....the line representing where the plane is.

    Diameter - Wikipedia, the free encyclopedia
     
  6. Garbz

    Garbz No longer a newbie, moving up!

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    The filter size is not indicated by phi but rather by "Ø" which is a Cyrillic letter.

    The focal plane symbol is ɸ which as far as I know really is a symbol and not used in any language.

    /EDIT: ϕ is the mathematical interpretation of the letter phi which is actually presented like Φ in the language.
     
    Last edited: Oct 2, 2009
  7. musicaleCA

    musicaleCA TPF Noob!

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    Noooo, it's Phi, or at least it is on all Canon lenses. Below is a shot of the front of my EF-S 10-22/3.5-4.5 USM. All Canon lenses I have illustrate the filter diameter in the same way. Perhaps Nikon is different?

    [​IMG]

    Eugh, I really need to clean that lenses...Stupid 18MP making everything show-up (for the curious, that's what 6400 looks like on the 7D without any PP noise-reduction).
     
  8. Dwig

    Dwig TPF Noob!

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    The proper symbol has a diagonal slash. It should not be exactly vertical. Typography being what it is, most fonts will lack the symbol. Some creations made from the proper lower case Latin "o" and a slash, "/", may have an overly vertical slash that is a characteristic of that font.

    The Canon lens you use for an example seems to have a slight slant to the slash. Not as much slant as would be proper, but not vertical either. It is just a rather poor rendition of the symbol. Its as if it was assembled using a slash from a rather condensed font where the slash was more vertical than in a more normal font.
     
  9. Derrel

    Derrel Mr. Rain Cloud

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    ...is Dwig finding fault with Canon's implementation of the filter size symbol and its incorrectly oriented slash??? He must be an anti-Canon, Nikon-using fanboy or something!:lol:

    Actually, I know what he means: for a long time, the filter diameter symbol slash's angle has been a decided diagonal, running from seven o'clock to one o'clock. The symbol on new Canon lenses has the slash running almost straight up and down,relative to the other lens inscriptions; the new Canon symbol has a very slight diagonal, with a slash that runs from, "six thirty to twelve thirty".

    Hey, I get it: Canon is ahead of everybody else! They start their slash at 12:30--while other,slothful lens makers begin their slashes at 1:00. Very subtle marketing message there, hidden in that Canon filter dia. symbol!
     
  10. musicaleCA

    musicaleCA TPF Noob!

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    As long as we all realize we're arguing semantics here. How about we settle on it being a circle with a line thingy through it? :lol:
     
  11. Dwig

    Dwig TPF Noob!

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    I guess I somewhat resemble that remark. If I don't count the "look prettys" that I once had in a rather large camera collection (300+, most long since sold off), I've owned and used only 3 Canons (Dial 35 and two QL-17s) while I've owned and used some 8 Nikons (RF, SLR, & digital) and two Leicas.

    I'm married and its a mixed marriage. I'm Nikon/Windows/tall/blond (when I had hair) and my wife is Canon/Mac/petite/brunette. The big difference, though, is "religion"; I was raised Warner Bros. and my wife was raised Disney.
     
  12. musicaleCA

    musicaleCA TPF Noob!

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    :lmao::lmao::lmao::lmao::lmao: You're killing me man. Killing me! :lol:
     

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