Filter advice needed

Discussion in 'Digital SLR' started by Arild P., Jul 9, 2006.

  1. Arild P.

    Arild P. Guest

    I've been reading about filters and believe I might need a couple.
    I'm vaguely familiar with circular-polarizing filters as I had one with
    my previous 35mm camera and also with my digital camcorder. I used them
    to remove reflections from windows (e.g. made it possible for me to
    take pictures through a bus or train window) and also get a deep,
    intense "exotic and tropical" look when shooting a beach/sea. Instant
    postcard shots!!!

    Back then I just bought a reasonably priced one, but from a reputable
    brand (can't remember if it was Habuba or B+H as I also bought a
    "protection" glass type "filter" at the time), but have since then
    heard that there's a great deal of difference between filters. Please
    explain the differences and what I should be looking for.

    Secondly, having experimented a lot with my newly purchased Canon Rebel
    XT/EOS-350D I've run into the exposure issue when taking say sunset
    shots, where the sunset is correctly exposed, but everything else just
    becomes a solhouette or very dark. I've heard about filters that can
    darken parts of the image (in this example the sunset sky) while the
    rest is left untouched, resulting in an overall image which is easier
    to find a good exposure for.
    Are these neutral density or graduated filters? At least that's what
    the luminous landscape "Understanding digital blending" article
    (http://www.luminous-landscape.com/tutorials/digital-blending.shtml)
    talks about.
    But the same article explains that you need to layer several filters on
    top of each other, use filter holders etc. I never knew it was that
    complicated! I'm sure I've seen a type of filter in the stores where
    half of it is dark and the other half is transparent. What fialters are
    these?

    I assume they work in much the same way as a circular polarizing filter
    where you (after having focused) rotate it until you get the result you
    want, then shoot.

    Lastly, my lens is a Sigma 17-70 f/2.8-4.5 which has a 72mm filter-size
    ring. I'm planning to soon get a second lens; a Canon 70-300 f/4-5.6 IS
    USM which has a 58mm filter-ring. From what I've heard I then have to
    buy a filter which fits the widest lens (i.e. 72mm), then buy an
    additional "adapter ring" for the narrower lens (i.e. 72mm -> 58mm).
    That way I don't have to buy a filter/filters for each lens.
    But in case I get serious about this hobby and buy even more lenses,
    then end up with a lens with a bigger filter size than 72mm, would it
    be a smarter move for me to start off with a filter in the biggest
    possible size (is that 77mm for Canon/canon-compatible lenses?), and
    buy an adapter ring for both lenses?
     
    Arild P., Jul 9, 2006
    #1
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  2. Arild P.

    rasilan Guest

    With any digital camera and filters you must make and use a custam white
    balance to get the use of the filters. eseast way to do his is put the
    filter on then take a pic of a white paper in the light conditions you will
    be shooting then goint white bal. and set the pic as white. and to darken
    just part of the pic and not the rest of the pic it is a grad. nutral
    density filter
     
    rasilan, Jul 9, 2006
    #2
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  3. Arild P.

    Bill Guest

    I rarely use filters with digital cameras because most of the time you
    can get the effect you want when post-processing the digital image. If
    you want deep blues in the sky and water, you can easily tweak the
    saturation to get the perfect image afterwards - no guess work.

    There are exceptions. The polarizer and gradient which I have and use as
    needed to reduce glare and over exposure scenarios.
    You want filters that are well made with good multicoated optical glass.
    The two most respected names around my area are B&W and Hoya.

    Canon and Nikon filters are good, but overpriced for what you get. Optex
    and Tiffen are cheap and are not recommended for serious work.
    Yes. A graduated filter is darker at the top to block out brighter light
    and still allow the lower portion to expose properly as well.
    Yes, and that's a good reason why you want lenses that have non-rotating
    front elements.

    Every time you re-focus, you have to adjust the filter to get the proper
    effect. And with some cheaper lenses, merely adjusting the filter can
    move the lense out of prime focus.
    Yes.
     
    Bill, Jul 9, 2006
    #3
  4. Arild P.

    Arild P. Guest

    I'm pretty clueless at the moment, so do you have any specific series
    or model numbers?
    I wouldn't know how to distinguish a good filter from a bad one.
    Then again I assume this whole thing is like choosing lenses, which
    I've asked about here a few weeks ago. Pros tell me that only "L"
    lenses are good enough while newbies tell me I'm fine with the
    excellent kit lens. I spent weeks looking through reviews of various
    lenses, keeping in mind what *I* needed the lens for and what would be
    good enough for *my* use, so I bought the Sigma 17-70 f/2.8-4.5 lens
    which I'm very happy with.
    Unfortunately I don't have the time at the moment to spend as much time
    searching for suitable filters, but suffice to say that I want good
    quality, but I'm not prepared to pay through the roof for something
    that is equivelant to "L" quality in lens terms, just because that's
    what the pros use.
    I'm starting out with photography (I've taken snapshots for years, but
    it's only recently that I've become really interested and serious about
    the hobby, spending time and effort learning things from the start),
    but what I buy should be quality and allow me to advance to the next
    level. If I ever do become a pro some day I'll probably reconsider all
    my equipment anyway.

    Good to know.
    What about other brands such as Hakuba, Sigma and Cokin?

    "Graduated filters" and "neutral density filters" are just two names
    for the same type of thing?

    My Sigma 17-70 is nice that way. The front element doesn't rotate.
    But apparently the second lens I'm about to buy (Canon 70-300mm f/4-5.6
    IS USM) does have a rotating front element.
    I've done a lot of research and it seems this is a good lens for my use
    and price-range. Is it a minor inconvenience or a problem that the
    front-element will rotate?
    I don't see any suitable equivelants to that lens (yes, I've considered
    the 70-200mm f/4L, but it's 100mm less (and yes, I know about the
    extender, but then we're talking about a lot more money in total
    again), and it doesn't have IS which will come in handy when not
    dragging a tripod along on my trips).

    Hmmmm... I can see that the latter might be a problem, and not just an
    inconvenience. Anyone reading this who's got a Canon 70-300 IS USM and
    use filters?
     
    Arild P., Jul 10, 2006
    #4
  5. Nope. A neutral density filter is one that darkens the scene - that is,
    it blocks light, but it blocks all colours equally (hence the neutral).
    A graduated filter is any filter that's uneven - the amount of
    filtering changes gradually. It's not a specific type of filter; it's a
    property of the filter. What you're looking for is a "graduated neutral
    density" filter - a neutral density filter that is darker on one side
    than on the other. (That said, if you ask for a graduated filter, most
    people will assume you mean graduated neutral density...but if you just
    ask for a neutral density filter, you'll get a non-graduated one, which
    is not what you want.)
    It's...a bit of a pain, but nothing terrible...depending. I use a
    polarizer on the 18-55 kit lens as well as by 75-300 IS USM; both have
    rotating front elements. In general, what I do is:
    - Focus
    - Adjust the polarizer
    - Focus again and take the picture

    This works, because adjusting the polarizer does knock the focus off a
    bit, but not very much (using autofocus, the front elements don't
    rotate very easily). When I re-focus, the polarizer will often be
    twisted slightly, but not to any degree that actually makes a
    difference in the image.

    However...if I were using manual focus for these images, I could see it
    being a real problem, because adjusting the polarizer would have a much
    bigger impact on the focus. Also, I have no experience with graduated
    netural density filters, but I suspect the slight adjustment during
    re-focusing might be more critical with them than it is with the
    polarizer. The polarizer can twist a couple degrees without having much
    visible effect, but getting an unlevel horizon line on the Grad ND
    might be a bigger deal.

    - Darryl
     
    madhobbit.geo, Jul 10, 2006
    #5
  6. Arild P.

    Bill Guest

    Mostly by name, in your case. I use Hoya filters because they cost a bit
    less than B&W but seem to work just as well.
    The cheaper lenses might be "good enough" for your needs.
    I wouldn't use a Sigma or Cokin unless it was thrown at me.

    :)

    I have no experience with Hakuba filters, if they even make them.
    Not really. A neutral density filter is one that has a neutral effect on
    the colours, and it darkens uniformly. While a graduated filter darkens
    with a gradient.

    You can have a graduated neutral density filter, which is often used for
    something like a sunset photo to darken the top half of the scene and
    allow the foreground in the bottom half to expose properly.
    You'll have to tweak it each time you focus, perhaps two times for each
    focus.
     
    Bill, Jul 10, 2006
    #6
  7. Arild P.

    Arild P. Guest

    And the same for filters?
    What kind of differences are there between high quality, excellent and
    expensive filters compared to "good quality", reasonably priced
    filters?
    I would think that expensive filters don't block as much light as the
    cheaper ones do, but are there other differences?

    Hehe :)
    That bad, eh?

    Yes! That's exactly what I'm looking for!!
    I'd love to get some nice sunset shots, but without turning the bottom
    part into all-silhouettes.
    Any specific recommendations for such a filter?
     
    Arild P., Jul 11, 2006
    #7
  8. Arild P.

    Bill Guest

    Oops...substitute "lenses" with "filters" in my line above.

    :)
    Low reflections, consistency of coatings, and optical clarity are the
    main reasons to buy good filters.

    Ideally a filter should not add or remove anything to an image, other
    than its intended purpose of course.
    Just visit a camera shop and have a look at the various offerings.

    Something such as a 1 stop light grey graduated neutral density filter
    should do the trick.
     
    Bill, Jul 11, 2006
    #8
  9. Well, that'll depend who you ask.

    When I picked up my circular polarizer, I went down to the local photo
    shop (one of the better places in the city, though probably not the
    best), and asked what my options were. The person I happened to be
    talking to was the prototypical grizzled old photographer; the guy
    that's been photographing for years, and doesn't care about tests or
    specs or technology or anything other than what the final picture
    actually looks like. He showed me their range, from their cheapest (an
    Optex filter) to their most expensive (B+W, I think), which was about
    3x the price. When I asked him what the difference was, he looked at me
    and just said "Nothing that the human eye can perceive."

    As soon as he said that, one of the other employees, a younger guy with
    a DSLR around his neck, piped up and said something to the effect of
    "Oh no, I disagree, I've always found that you don't get good results
    with anything less than such-and-such a brand." The first guy looked at
    him with an expression that said, basically, "When you've been
    photographing half as long as I have, then you can tell me what's good
    and what's bad."

    So...I bought the cheap one. That's all I wanted to spend anyway. Who
    was right? Hard to say. I've got no complaints about the performance of
    my Optex C-POL, but I've never used a more expensive one, so maybe I
    don't know what I'm missing.
    Well, the whole point of a neutral-density filter is that you -want- it
    to block light. With a cheaper ND filter, the most likely problems
    would be more flare (if it's not as well coated), or an uneven colour
    cast (though I've also read of expensive filters with this problem).
    I don't think the aforementioned photo store even stocked these. I
    think Optex is as cheap as they'll go.

    - Darryl
     
    madhobbit.geo, Jul 11, 2006
    #9
  10. Arild P.

    babalooixnay Guest


    Look at the Cokin P size filters for Sunsets. They are square with
    slide in filters. You can get adaptor rings for various size lenses
    and because they slide you can adjust for the horizon depending on
    composition. Graduated ND come in various densities and hardness of
    differential zones. Different brands use different coding for density
    but essentially 1 stop, 2 stops, 3 stops, etc. Zones can be hard, soft
    etc. for the transition from ND to clear. Straight NDs are for when
    you have a bright scene but want a slow shutter beyond your cameras
    range, e.g. soft water movement in bright light.

    The circular polarizer is necessary for anti-glare and the circular
    aspect is critical for auto focus. For anything else you can do it in
    post-processing with digital
     
    babalooixnay, Jul 11, 2006
    #10
  11. Arild P.

    David Kelson Guest

    ANYONE ever use Heliopan filters from Germany? Any thoughts? Regards,
    David
     
    David Kelson, Jul 11, 2006
    #11
  12. Arild P.

    Arild P. Guest

    My thoughts exactly! It's great to meet someone on the same wavelength
    :)
    It's sort of like my choice of lens. I don't know what I may be missing
    with a more expensive one, but I'm happy with what I've got. Ignorance
    is bliss ;-)

    To put it the other way round; if you'd gotten the most expensive one
    you would probably be happy with the results but you'd never know if
    the filter at 1/3 of its price would have been "good enough" for you.


    The problem with *total* ignorance however is that you don't know where
    to start, which is why i'm asking for advice here.
    Bill just pointed out a few things worth taking into consideration:
    reflections, consistency of coatings etc. I wouldn't know how to
    determine which filter has low reflection and a consistent coating by
    looking at the packaging in the store. They all look the same to me.
    And most people don't have the money or time to do extensive
    testing/comparing before ending up with something they like.

    True, I want it to block light in half the frame, but the other half
    shouldn't be blocked at all.
    I guess I was really thinking about the polarizing filter when I wrote
    the above.
    I've just read however that polarizing filters do in fact block out
    some of the light.

    I'll take a not of those issues you mention about flare and uneven
    cast.

    Someone else recommended that I get Cokin because of their versatility.
    I looked up their website and found out what he meant. They have this
    "frame" which you get in various sizes, then place the different
    filters which consist of a square piece of glass in the frame.
    However, I don't see why this is any better than buying "normal"
    filters and adapter rings for your other lenses that have a smaller
    diameter. Those Cokin filters look rather fragile to me, and without
    any metal/plastic around the edges I'd be careful handling them and
    possible end up dropping them on the ground. I would also think that
    their system is patented meaning I would have to continue buying Cokin
    branded filters as opposed to choosing between different brands for
    additional filter types I'd need if going for the normal threaded type.

    Any reason why I should look into Cokin's system as opposed to normal
    filters with ring-adapters (so I can use them with several lenses)?
     
    Arild P., Jul 12, 2006
    #12
  13. Arild P.

    Arild P. Guest

    You mean they just don't slide in the "frame" and lock, but they extend
    *past* the frame meaning they can be moved up and down to pass
    different parts of the filter through to the lens?

    I think I have a reply to my own question earlier about why Cokin
    filters might be preferred over "normal" filters; you can stack several
    filters in one holder/frame, combining the properties of many different
    filters.
    I can see how this can come in handy with neutral density filters where
    you want to freely define where the darkening occurs.
    But apart for the versatility I can also see myself spending lots of
    time with the filters (and also a lot more to drag around) instead of
    taking pictures ;-)

    Maybe I just need something simple for now, even though it might mean
    to start all over again if I get to a more professional stage some day.

    There's also something called a "linear polarizer". What are the
    differences between the two?

    I agree that the rest can probably done in Photoshop (colours, bokeh
    etc.) but not the polarizing and darkening of a section in order to get
    a more even exposure.
    Apart from the gradient filter I might see myself getting a neutral
    density filter for snow and white-sand beach shots.

    Now that I know what I need I just need to figure out the brand/model
    and specs ;-)
     
    Arild P., Jul 12, 2006
    #13
  14. Arild P.

    Bill Guest

    There is only one way to be sure - buy the cheaper stuff and see if it's
    good enough for what you want. If it is, great. If not, exchange it.

    :)
    You generally get what you pay for...
    In the beginning I bought a few cheaper filters because I couldn't tell
    the difference either, and the salesman probably got a higher commission
    talking me into buying the cheaper Tiffen filters.

    But after using the camera and filters, and getting the opportunity to
    use better filters and lenses through a friend, I realized the
    differences.

    Granted, they can be subtle in some situations, but the difference is
    definitely there.

    But...is that difference worth an extra $20 or $30 per filter to you?

    I'll say this...for my girlfriend, mom&dad, my brother, several friends,
    the answer is a very simple NO. They get 4x6 or 5x7 prints and can't
    tell the difference, and that's all they need.

    Me...I want more.
    With a gradient filter, you generally don't need to worry about how much
    or where - the meter will help compensate for you, and you can always
    adjust it slightly in post processing if you wanted more or less, or to
    change the half-way point.
    I like the versatility too...just not the quality.
     
    Bill, Jul 12, 2006
    #14
  15. Arild P.

    Arild P. Guest

    I don't understand how it can't matter how much (how dark) the filter
    is, because it'll "equalize" the darkest and brightest parts against
    each other, won't it? So the end result will depend on just how bright
    the sun is (or the brightest area) in comparison to the darkest area.

    However, I believe I read somewhere that a -1 drop on the meter due to
    the filter would be good enough and the most versatile filter of this
    type for most occasions. How intense did you get yours?
     
    Arild P., Jul 12, 2006
    #15
  16. Arild P.

    Arild P. Guest

    I've had a look at the Hoya website and besides the usual polarizing
    filters (it seems I need the *circular* polarizing filter as opposed to
    a "linear" polarizing filter according to their page:
    http://www.hoyafilter.com/products/hoya/gf-04.html), but I came across
    something they call a "UV-PL-Cir filter"
    (http://www.hoyafilter.com/products/hoya/gf-05.html) which is a hybrid
    between a circular polarizer and an ultra-violet filter, said to remove
    haze from outdoor pictures in addition to being a normal polarizing
    filter.
    Is this a better solution than the normal PL-Cir filter?
    I haven't found any prices yet, but I assume it's more expensive than
    the plain PL_Cir filter.

    I couldn't find any graduated neutral-density filters at their site.

    I also read somewhere that when buying a filter you should try to find
    ones with a thread at both sides so an additional filter can be
    attached on top of it if needed. Sounds useful.
     
    Arild P., Jul 12, 2006
    #16
  17. Arild P.

    jeremy Guest

    On film cameras, polarizers had the potential to yield dramatic results by
    darkening skies and by eliminating reflections from areas such as water
    surfaces and window glass. Most of the TTL exposure systems are fooled by
    linear polarizers, and the recommendation has been, for a long time, to use
    circular polarizers. I have used linear polarizers on my film cameras
    without problems, but that may have been because negative film has a wide
    tolerance for exposure variations.

    You'd be better off using a circular polarizer on a DSLR, just to be certain
    that your exposures are perfect.

    UV is another matter. We know that, even though ultra-violet light is
    beyond the range that the human eye can see, that is not the case for many
    film emulsions. Film see UV light as fog. Color emulsions often show UV as
    a bluish fog. So it is advantageous to filter it out.

    But with modern multicoated lenses, the coatings themselves filter out UV
    light, making a UV filter unnecessary. I use them as protection for the
    front elements on my lenses, but I don't notice any difference in the image
    quality if I shoot without a UV filter, because my lenses do the UV
    filtering anyway.

    Another factor is how efficient the UV filter is at removing ultraviolet
    light in the first place. Bob Monaghan's site had a list of which filters
    actually were good at filtering UV, and as I recall, the Tiffen filter did a
    much better job than other brands. (Of course, if you are using multicoated
    lenses, it may all be a moot point).

    What I do not know--and perhaps someone can enlighten us--is whether digital
    camera sensors are adversely affected by UV as film is. I suspect that they
    are not, because I've seen no one pushing UV filtration for digital cameras.
    You might be just as well of using a standard linear polarizer.

    Just be aware that Hoya has three distinct lines of filters. Their
    lowest-quality line uses cheap glass, and may result in image degradation.
    They are often put up for sale on eBay at low prices, and people buy them
    unaware that they are getting a substandard product. The fact that the Hoya
    brand appears on the package does not of itself indicate high quality.

    You can get a lot of information about a number of different filter brands
    at this site:

    http://www.2filter.com/welcometo.html

    Their prices are on the high side, but the site is still an excellent
    information resource.

    I would recommend that you use only high quality filters if you use them at
    all. Erwin Puts, the Leica specialist, noted that an excellent filter may
    introduce up to 2% image degradation, while a cheap filter can negatively
    affect image quality by 10%. If you are using a zoom lens, and have to buy
    only a single filter (as opposed to needing multiple filters for several
    different lenses), it might as well be a good one.
     
    jeremy, Jul 12, 2006
    #17
  18. Arild P.

    Bill Guest

    Mine is a 1 stop gradient ND. It's dark enough to shoot the sun nicely
    for strong sunsets, bright stadium lights, or other similar situations.

    I've used it in both horizontal and vertical positions to obtain the
    exposure I wanted.
     
    Bill, Jul 12, 2006
    #18
  19. Arild P.

    AaronW Guest

    Digital is not sensitive to UV.
    But after the exposure, it is easy to check the LCD and histogram, and
    adjust exposure to take another shot. It is also easy to do bracketing.

    Because the meter is not perfect anyway, without a polarizer you may
    need to adjust exposure as well. And because circular polarizer has one
    additional film in the filter to degrade picture, I prefer linear
    polarizer.

    http://digitcamera.tripod.com/#slr
     
    AaronW, Jul 13, 2006
    #19
  20. Arild P.

    AaronW Guest

    Most have front thread. Some wide angle filters don't, to keep it thin,
    to minimize vignetting.

    http://digitcamera.tripod.com/#slr
     
    AaronW, Jul 13, 2006
    #20
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