newbie question: polarizer + uv filter?

Discussion in 'Digital Photography' started by Hyrum Mortensen, Nov 17, 2004.

  1. Hi,

    I was given a Canon 20D as a gift recently. It came with a polarizer
    filter. Can a polarizer replace the functionalities of a UV filter?
    In other words, is there any advantage of adding a UV filter if I
    already have a polarizer filter?

    Thanks
    Hyrum Mortensen, Nov 17, 2004
    #1
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  2. Hyrum Mortensen wrote:
    > Hi,
    >
    > I was given a Canon 20D as a gift recently. It came with a polarizer
    > filter. Can a polarizer replace the functionalities of a UV filter?
    > In other words, is there any advantage of adding a UV filter if I
    > already have a polarizer filter?
    >
    > Thanks


    UV filter's function is to block UV light.
    Polarizer filter's function is to filter light based on it polarized
    direction.

    No neither filter replaces the other.

    Most people have little idea of what the function of a UV filter is.
    They just put one on every lens they have to "protect" the lens. Most are
    not sure what they are protecting it from, but someone, likely the camera
    salesman who sold it to them, told them they needed it.

    There are some situations where using such a filter would be wise.
    Blowing sand or a situation that will call for more than average lens
    cleaning. However adding one also usually increase lens flare which is
    generally consider a bad thing and a lens shade will provide much of the
    protection of a UV filter and decrease lens flare.

    It appears most if not all of today's consumer digital cameras are
    insensitive to UV light, so you don't need the UV filter to filter out UV
    light, like a film camera may need at times.

    You would not want to leave the polarizing filter on all the time as it
    does change the resulting image and it can as easily reduce the quality of
    the image as improve it and it also blocks considerable light. Polarizing
    filters should be used selectively and need to be adjusted for each image.

    --
    Joseph E. Meehan

    26 + 6 = 1 It's Irish Math
    Joseph Meehan, Nov 17, 2004
    #2
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  3. In article <>, Hyrum
    Mortensen <> wrote:

    > I was given a Canon 20D as a gift recently. It came with a polarizer
    > filter. Can a polarizer replace the functionalities of a UV filter?
    > In other words, is there any advantage of adding a UV filter if I
    > already have a polarizer filter?


    The UV is pretty much worthless. Just puts a cheap piece of glass in
    front of an expensive one.

    The polarizer will reduce reflections at about a 30-degree angle and
    enhance blue skies at a right angle to the sun.
    Randall Ainsworth, Nov 17, 2004
    #3
  4. Hyrum Mortensen

    Bob Salomon Guest

    In article <>,
    (TheNewsGuy(Mike)) wrote:

    > It just adds another two glass surfaces to
    > clean and reflect light.


    Do they?

    If the filter is on the lens then dust can not settle on the lens.
    Neither can fingerprints. In fact, dust and fingerprints and other
    external matter like water or soda, coffee, smoke, etc. can only land on
    the front surface of a filter when it is on the camera. They can not
    reach either the lens itself or the rear surface of the filter so you
    would only need to clean the front surface of the filter. Scratch it and
    you can throw it away and just replace the filter. Scratch that camera
    lens and you probably will replace the camera.

    Now for "reflect light". An uncoated glass to air surface - an uncoated
    filter for example as all camera lenses are coated - will lose about 4%
    of the light striking it due to reflection.

    A good coated filter (both sides coated) with a single coat like
    Heliopan uses passes up to 97.5% of the light striking it.

    And with a modern multi coated coating like the SH-PMC from Heliopan
    over 99.5% of the light striking passes through the filter. And SH-PMC
    also repels dust and moisture to keep cleaning to a minimum.

    So no you are not always adding two additional glass layers to clean and
    you don't reflect enough light to matter with modern hard coatings.

    --
    To reply no_ HPMarketing Corp.
    Bob Salomon, Nov 17, 2004
    #4
  5. Hyrum Mortensen

    Jim Guest

    "Joseph Meehan" <> wrote in message
    news:X8Mmd.12823$...
    >
    > Most people have little idea of what the function of a UV filter is.
    > They just put one on every lens they have to "protect" the lens. Most are
    > not sure what they are protecting it from, but someone, likely the camera
    > salesman who sold it to them, told them they needed it.
    >

    Once upon a time, I dropped my F3 which had the 100-300 lens mounted
    thereon. All that happened was that the UV filter cracked, but the rest of
    the lens and of course the camera were unhurt.

    So, which would you rather replace after such an incident? Would it be the
    $50 filter or the $300 lens?

    Besides, I was in Yellowstone Park where access to camera repair facilities
    requires (at least) a trip to Jackson Hole, Wy.

    Jim
    Jim, Nov 17, 2004
    #5
  6. Hyrum Mortensen

    YAG-ART Guest

    On 17 Nov 2004 09:40:12 -0800, (Hyrum Mortensen)
    wrote:

    >Hi,
    >
    >I was given a Canon 20D as a gift recently. It came with a polarizer
    >filter. Can a polarizer replace the functionalities of a UV filter?
    >In other words, is there any advantage of adding a UV filter if I
    >already have a polarizer filter?


    You loose some light with a CP filter, you dont with a UV
    YAG-ART, Nov 17, 2004
    #6
  7. Hyrum Mortensen

    Jeremy Guest

    "Hyrum Mortensen" <> wrote in message
    news:...

    > In other words, is there any advantage of adding a UV filter if I
    > already have a polarizer filter?
    >


    It is considered inappropriate to combine both a polarizer and a UV. Too
    many air-to-glass surfaces to add to flare.

    I have always used UV or Skylight filters on my 35mm lenses--mainly to keep
    the front elements clean and free of dust, dirt and smudges. I happen to be
    one of those cleanliness freaks, and I would most certainly have cleaning
    marks on my lenses by now if I didn't use protective filters.

    There are two schools of thought on this subject. I am of the opinion that
    a GOOD QUALITY UV filter adds little to image degradation and adds much in
    the way of keeping the lens clean.

    Erwin Puts, the renowned Leica lens specialist, attributes a 2% image
    degradation when lenses have GOOD UV filters attached. That compares with
    10% degradation when CHEAP filters are used.

    By far, your image will suffer much more simply by handholding the camera
    rather than using a tripod.

    Many of my 35mm prime lenses are 3 decades old, and they have no cleaning
    marks etched into their front elements, and they are dust-free. I would
    prefer to sacrifice a filter rather than risk dirtying up an irreplaceable
    lens. Besides, I can always remove the filter if the shot is so critical
    that a filter might degrade the image too much. I have yet to have come
    upon such a situation.
    Jeremy, Nov 17, 2004
    #7
  8. Bob Salomon wrote:
    > In article <>,
    > (TheNewsGuy(Mike)) wrote:
    >
    >> It just adds another two glass surfaces to
    >> clean and reflect light.

    >
    > Do they?
    >
    > If the filter is on the lens then dust can not settle on the lens.
    > Neither can fingerprints. In fact, dust and fingerprints and other
    > external matter like water or soda, coffee, smoke, etc. can only land on
    > the front surface of a filter when it is on the camera. They can not
    > reach either the lens itself or the rear surface of the filter so you
    > would only need to clean the front surface of the filter. Scratch it and
    > you can throw it away and just replace the filter. Scratch that camera
    > lens and you probably will replace the camera.
    >
    > Now for "reflect light". An uncoated glass to air surface - an uncoated
    > filter for example as all camera lenses are coated - will lose about 4%
    > of the light striking it due to reflection.
    >
    > A good coated filter (both sides coated) with a single coat like
    > Heliopan uses passes up to 97.5% of the light striking it.
    >
    > And with a modern multi coated coating like the SH-PMC from Heliopan
    > over 99.5% of the light striking passes through the filter. And SH-PMC
    > also repels dust and moisture to keep cleaning to a minimum.
    >
    > So no you are not always adding two additional glass layers to clean and
    > you don't reflect enough light to matter with modern hard coatings.


    It is not the loss of that small amount of light that is the problem.
    It is the flare of that small amount of light showing up in the dark areas
    of the image that are a problem.

    --
    Joseph E. Meehan

    26 + 6 = 1 It's Irish Math
    Joseph Meehan, Nov 17, 2004
    #8
  9. Jim wrote:
    > "Joseph Meehan" <> wrote in message
    > news:X8Mmd.12823$...
    >>
    >> Most people have little idea of what the function of a UV filter is.
    >> They just put one on every lens they have to "protect" the lens. Most
    >> are
    >> not sure what they are protecting it from, but someone, likely the camera
    >> salesman who sold it to them, told them they needed it.
    >>

    > Once upon a time, I dropped my F3 which had the 100-300 lens mounted
    > thereon. All that happened was that the UV filter cracked, but the rest
    > of
    > the lens and of course the camera were unhurt.
    >
    > So, which would you rather replace after such an incident? Would it be
    > the
    > $50 filter or the $300 lens?
    >
    > Besides, I was in Yellowstone Park where access to camera repair
    > facilities
    > requires (at least) a trip to Jackson Hole, Wy.
    >
    > Jim


    Let's see. At a ratio of 50 - 300 one out of 60 lenses would need to be
    totalled to make the math work out even.

    I doubt if one out of 60 is damaged.

    I did have one of my cameras thrown at me once (long story very nice
    girl) and it happened to have a filter on it at the time. As it turned out
    the filter was jamed onto the filter threads and cracked so I had to have
    the lens repaired. With out the filter, it would have likey damaged the
    filter ring, but I would not have bothered to repair that. With a lens
    hood there would likely have been no damage to the lens, but that is just my
    judgment.

    While working as a professional, many years ago, I had a number of
    lenses damaged and used equipment that had lenses damaged by other
    photographers. Never once did I ever need to have any repairs made. Just a
    few scratches and chips on the lenses, none of which reduced the image
    capabilities of the lens.

    Sounds like expensive insurance to me and that is not accounting for the
    extra flare that the filter may cause.


    --
    Joseph E. Meehan

    26 + 6 = 1 It's Irish Math
    Joseph Meehan, Nov 17, 2004
    #9
  10. Hyrum Mortensen

    TheNewsGuy Guest

    On 17 Nov 2004 09:40:12 -0800, (Hyrum Mortensen)
    wrote:

    >Hi,
    >
    >I was given a Canon 20D as a gift recently. It came with a polarizer
    >filter. Can a polarizer replace the functionalities of a UV filter?
    >In other words, is there any advantage of adding a UV filter if I
    >already have a polarizer filter?


    You don't want to leave a polarizing filter on the camera at all time
    - it will filter out a lot of light and reduce your f-stop and speed
    to lower than necessary levels. It works great indoors to cut out
    reflections on shiny objects like windows, glass table tops, etc. and
    wonderful outdoors to enhance an already blue sky and cut out
    reflections that dilute the colours in buildings. But it is not for
    "all time" use.

    The UV filter will cut through a UV haze ( at altitude) or in distant
    landscape shots.

    Again some people, like me, (not that I am an expert professional,
    just an interested amatuer ) do not recommend leaving any filter on
    the camera at all times. It just adds another two glass surfaces to
    clean and reflect light.


    Hope that helps



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    TheNewsGuy, Nov 17, 2004
    #10
  11. Hyrum Mortensen

    Charles Guest

    On Wed, 17 Nov 2004 21:04:50 GMT, "Joseph Meehan"
    <> wrote:

    >Jim wrote:
    >> "Joseph Meehan" <> wrote in message
    >> news:X8Mmd.12823$...
    >>>
    >>> Most people have little idea of what the function of a UV filter is.
    >>> They just put one on every lens they have to "protect" the lens. Most
    >>> are
    >>> not sure what they are protecting it from, but someone, likely the camera
    >>> salesman who sold it to them, told them they needed it.
    >>>

    >> Once upon a time, I dropped my F3 which had the 100-300 lens mounted
    >> thereon. All that happened was that the UV filter cracked, but the rest
    >> of
    >> the lens and of course the camera were unhurt.
    >>
    >> So, which would you rather replace after such an incident? Would it be
    >> the
    >> $50 filter or the $300 lens?
    >>
    >> Besides, I was in Yellowstone Park where access to camera repair
    >> facilities
    >> requires (at least) a trip to Jackson Hole, Wy.
    >>
    >> Jim

    >
    > Let's see. At a ratio of 50 - 300 one out of 60 lenses would need to be
    >totalled to make the math work out even.
    >
    > I doubt if one out of 60 is damaged.
    >
    > I did have one of my cameras thrown at me once (long story very nice
    >girl) and it happened to have a filter on it at the time. As it turned out
    >the filter was jamed onto the filter threads and cracked so I had to have
    >the lens repaired. With out the filter, it would have likey damaged the
    >filter ring, but I would not have bothered to repair that. With a lens
    >hood there would likely have been no damage to the lens, but that is just my
    >judgment.
    >
    > While working as a professional, many years ago, I had a number of
    >lenses damaged and used equipment that had lenses damaged by other
    >photographers. Never once did I ever need to have any repairs made. Just a
    >few scratches and chips on the lenses, none of which reduced the image
    >capabilities of the lens.
    >
    > Sounds like expensive insurance to me and that is not accounting for the
    >extra flare that the filter may cause.



    I agree, mostly, but try your math again.


    --

    - Charles
    -
    -does not play well with others
    Charles, Nov 17, 2004
    #11
  12. Hyrum Mortensen

    Jeremy Guest

    "Joseph Meehan" <> wrote in message
    news:S1Pmd.12841$...
    >
    > Let's see. At a ratio of 50 - 300 one out of 60 lenses would need to

    be
    > totalled to make the math work out even.
    >


    The effectiveness of a simple filter in preventing damage to a dropped lens
    is probably negligible, but the use of a filter to keep the lens front
    element clean is clearly advantageous. Even if one does not subject his
    lenses to wind, surf, sand, etc., lens elements still get dirty from having
    dust settle on their surfaces, and many klutzes like me have a nasty
    tendency to smudge the lenses with our fingers.

    I would prefer that the filter take the hit, rather than the lens itself.
    Especially if the lens is one that is not easily replaced (the line that I
    use has not been in production for 25 years--it is not like I can just walk
    into any camera shop and pick up new ones). Filters I can replace. Lenses
    I can't--at least not easily.

    Many people mention increased flare as a reason to avoid filters, but I
    wonder if the degree of increased flare has been measured? I suspect that
    most people who complain about flare do not routinely use lens shades--and
    I'd bet that they get more flare by not using lens shades than they would
    get from the addition of a protective filter.

    My point being that the image degradation resulting from the addition of a
    quality filter is probably too small to have any visible impact. Dirty,
    smudged or dusty lens surfaces affect image quality more than an additional
    (clean) filter.

    I could never understand why so many people have characterized use of a
    filter for protection as merely a tactic used by camera dealers to make more
    money. The logic behind using filters as protective surfaces makes a lot of
    sense to me.
    Jeremy, Nov 18, 2004
    #12
  13. "Jeremy" <> wrote in message
    news:MqTmd.2474$...
    >
    > "Joseph Meehan" <> wrote in message
    > news:S1Pmd.12841$...
    >>
    >> Let's see. At a ratio of 50 - 300 one out of 60 lenses would need to

    > be
    >> totalled to make the math work out even.
    >>

    >
    > The effectiveness of a simple filter in preventing damage to a dropped
    > lens
    > is probably negligible, but the use of a filter to keep the lens front
    > element clean is clearly advantageous. Even if one does not subject his
    > lenses to wind, surf, sand, etc., lens elements still get dirty from
    > having
    > dust settle on their surfaces, and many klutzes like me have a nasty
    > tendency to smudge the lenses with our fingers.
    >
    > I would prefer that the filter take the hit, rather than the lens itself.
    > Especially if the lens is one that is not easily replaced (the line that I
    > use has not been in production for 25 years--it is not like I can just
    > walk
    > into any camera shop and pick up new ones). Filters I can replace.
    > Lenses
    > I can't--at least not easily.
    >
    > Many people mention increased flare as a reason to avoid filters, but I
    > wonder if the degree of increased flare has been measured?


    Yes, of course conditions make any measurement only applicable to the
    specific test. However in general, I would expect a good filter ($60 should
    get you a good filter) or better should not be noticeable by most people
    including most professionals most of the time. A cheap filter is likely to
    be spotted in most flare situations by most professions and the more
    critical non-professionals.

    > I suspect that
    > most people who complain about flare do not routinely use lens shades--and
    > I'd bet that they get more flare by not using lens shades than they would
    > get from the addition of a protective filter.


    Very true.

    >
    > My point being that the image degradation resulting from the addition of a
    > quality filter is probably too small to have any visible impact. Dirty,
    > smudged or dusty lens surfaces affect image quality more than an
    > additional
    > (clean) filter.


    I suspect that depends on the person and the environment in which they
    work. I seldom have any need to clean a lens. Others may have far more
    need to clean lenses, still more over clean their lenses which can result in
    more damage and problems than under cleaning. In the old days (Yea I'm that
    old) the early coatings on lenses were very soft and just a simple
    reasonable careful cleaning could damage it. Today's coatings are far
    better and the need is IMO just not there for a filter for most users. BTW
    often the smudge that many people fee is gong to impact their image and must
    be cleaned off is often not a smudge at all and does not need any attention.

    If you or anyone else is happy with what they are doing, and they get
    the images they like, then that is what this is all about and they should
    feel good about what ever way they want to treat their camera equipment.

    >
    > I could never understand why so many people have characterized use of a
    > filter for protection as merely a tactic used by camera dealers to make
    > more
    > money. The logic behind using filters as protective surfaces makes a lot
    > of
    > sense to me.
    >


    Since I was once a photo salesman I know the pressure that was put on
    them to sell those filters. I was lucky that I never worked for one that
    expected the hard sell or the Infomercial type tactics and I never allowed
    my employees to do it when I was the manager. But I sure saw a lot of fear
    tactics used to sell those filters just like they use today to sell grossly
    overpriced insurance policies they like to call extended warrantees. I
    sometimes get a little carried away.



    --
    Joseph E. Meehan

    26 + 6 = 1 It's Irish Math
    Joseph Meehan, Nov 18, 2004
    #13
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