Neutral Density Filters...

Discussion in 'Photography 101' started by RedOctober25, Oct 16, 2010.

Page 1 of 3
  1. RedOctober25

    RedOctober25 Member

    Okay, after seeing all the amazing fireworks photos using ND Filters I would like to get one to try out. ; But which one should I get. ; I realize that you basically lose f-stops per the density, but what works best for fireworks. ; Any suggestions would be helpful.

    My Camera is a Sony DSC-H50 (f2.7-8, 1/4,000-30").

    Also, when using an ND filter, what is the typical setting for fireworks? ; (At PM2k09 and without ND I was shooting at 1/20-1" on average)
     
    RedOctober25, Oct 16, 2010
    #1
  2. Roger

    Roger Member Staff Member

    I guess it would depend on the definition of "best".

    You would have to change your settings based on how dark of a filter you get, and unfortunately there is no mandatory standard for telling you how to compare the different filter manufacturers. ; I think those incredible pics you've seen used an 8 stop filter, which means that if you had a setting of 1 sec exposure before, you'd need well over 120 seconds unless you reduce your aperture as well.

    For a P&S I'm guessing a 2 or 4 stop filter would be the best, as I don't think you can stop down the lens as much as the interchangeable lens cameras. ; (I have to start using that term as we are seeing the change away from optical viewfinder SLRs to eventually mirrorless)
     
    Roger, Oct 16, 2010
    #2
  3. RedOctober25

    RedOctober25 Member

    Okay, so if I were to get a 4 stop filter (ND16 = 1.2) then if normally f-2.8 1/30 the filter would give me the same result if using f-8 4" (or did I do the math backwards on that one?) exposure wise. ; I went in and looked at the EXIF Data of one of my favorite fireworks photos I took at PM2K9 and it was at f-5.6/2", so if I wanted to run the shutter for 8" then I would use the ND16(1.2) at f22? (of which my camera does not reach). ; Again, am I doing the conversion right or is it bass ackwards?
     
    RedOctober25, Oct 16, 2010
    #3
  4. Roger

    Roger Member Staff Member

    Okay a 4 stop filter would move 2 sec at f/5.6 to 8 sec at f/11. ; Two stops in both.
     
    Roger, Oct 16, 2010
    #4
  5. Tim

    Tim Administrator Staff Member

    remember, the ND filter affects only the shutter speed. ; it has not effect on f/stop or depth of field.
    for the best math, take f/stop out of the equation.
     
    Tim, Oct 16, 2010
    #5
  6. RedOctober25

    RedOctober25 Member

    Okay, so what it is doing is moving the shutter from 2"-to-4"-to-8" (=2) and the f-stop from 5.6-to-8-to-11 (=2) (and then 2+2=4 stops total)? ; So a 30" exposure with a four stop ND filter would let the same light as 2" with no filter at any given f-stop (2"-to-4"-to-8"-to-15"-to-30")? ; And thereby increase the number of fireworks bursts with the same amount of light admitted to the camera.
     
    RedOctober25, Oct 17, 2010
    #6
  7. Roger

    Roger Member Staff Member

    Yes.

    In theory. ; Back in the days when you poured hazardous chemicals down the drain after processing your film in a "darkroom", you had to worry about reciprocity, where when your exposure time went beyond a few seconds, the actual f/stops between each one actually were much smaller than usual. ; Haven't researched enough to say if that is really true for digital or not, but I think it does come into play as almost every camera around has a "long exposure noise reduction" ability. ; Then again it could be one of those CMOS v CCD arguments. ; Almost every P&S camera has a CCD in it; almost every new interchangeable lens digital camera is now using CMOS.
     
    Roger, Oct 17, 2010
    #7
  8. Tim

    Tim Administrator Staff Member

    Yes, red, you are correct. ;
    The ND filter is like putting sunglasses on your lens to cut the amount of light getting in at any given moment. ; Closing the aperture has the same effect on light but will also. Increase depth of field. ; You can also drop the ISO to decrease light sensitivity as well.

    So... ; 1/sec at ISO 400 at f/5.6
    Add 4 stop filter becomes 15 seconds at f/5.6 at 400
    Cut ISO to 100 becomes 60 seconds at 100 at f/5.6 at 100
    Stop down lens to f/8 becomes 120 seconds at f/8 at 100
    And so own.

    Also filters are stackable for added effect.
    I have an ND 400 filter that is so dark I cannot see thru the viewfinder in daylight. ;
     
    Tim, Oct 17, 2010
    #8
  9. RedOctober25

    RedOctober25 Member

    so every step wether it be a step in ISO, f-stop, or shutter speed counts as 1 step in a four step nd filter. ; Okay, I might not have the mastery of this down quite yet, but this will give me a great starting point (since I have to thread these onto my Hood to use and it is a 72mm ring) for a single ND filter.
     
    RedOctober25, Oct 17, 2010
    #9
  10. gary

    gary Member

    get a 72 up to 77mm step up ring, these are very cheap, and if you should ever make the move to more interchangeable gear, 77mm is the standard for a lot of fast primes and zooms, saves replacing an expensive filter because it no longer fits onto your lens. ; also keep in mind that the cokin P type filters are very available, many types and less expensive than threaded ring types, BUT, those square/rectangle filters break easy and with the holder can take up a lot of room in a gear bag
     
    gary, Oct 17, 2010
    #10
  11. Tim

    Tim Administrator Staff Member

    more or less but take the filter out of the equation for a moment. ; the term "stop" refers to a doubling or halving of the amount of light that is hitting the camera sensor. ;

    there are stops of aperture, shutter, and ISO. ;
    going from 1/200 to 1/400 *OR* 1/100 represents one more or less stop of shutter speed. ;
    going from f/8 to f/11 *OR* f/5.6 is one more or less stop of aperture. ;
    going from ISO 400 to ISO 800 *OR* ISO 200 is one more or less stop of ISO. ;

    generally, cameras are set up to allow you to change stops in 1/3 increments (except ISO which is usually (not always) in full stops). ; adding the filter just cuts the amount of light getting into the camera, much like sunglasses cut the light getting into your eyes.
     
    Tim, Oct 17, 2010
    #11
  12. Scottwdw

    Scottwdw Member

    And since the ND filter effects the light going into your lens, your camera's meter will react accordingly. ; I know night time fireworks shooting does need the math. ; :) ;

    Most of the time I use bulb mode for fireworks shooting so, using a 4-stop ND filter, I will need to keep the shutter open much longer than without one. ; That's why you see 40, 60, 80, 100+ second shutter speeds on flickr firework photos a lot these days.
     
    Scottwdw, Oct 21, 2010
    #12
  13. mainstreet1997

    mainstreet1997 Member

    Woooaaah its way to early for me to understand the math on this! I just figured out f stops you guys! :p ; But Im still thinking about an ND filter. Im LOVING everyone's firework shots with these. Working on the birthday/Christmas wish list right now. Any reccomendations on which ND filter I should be looking at?
     
    mainstreet1997, Oct 24, 2010
    #13
  14. mainstreet1997

    mainstreet1997 Member

    bump.
     
    mainstreet1997, Oct 29, 2010
    #14
  15. gary

    gary Member

    i'd say start with a 2 stop nd, shoot with that for awhile to get the feel for slowing down water, etc, then get a graduated or split filter, these have the dark part halfway down/or fade to darker gradually, looking at them on the b&h site will give you a better idea of what i'm talking about, also get on down to that most wonderful of american traditions, the public library, there are some very good books out there that explain and demonstrate a whole lot about filters and their use.
    but once again i strongly recommend always getting whatever you choose in 77mm, and getting step up rings for your smaller diameter lenses. it's something i've done myself, and i use these really cheap step up rings, no need to get the brass ones
     
    gary, Oct 30, 2010
    #15
  16. mainstreet1997

    mainstreet1997 Member

    So does that mean i should get an ND Filter for my "biggest" lens size and then get the adapter so my ND Filter will fit on all my lenses?
     
    mainstreet1997, Oct 30, 2010
    #16
  17. Roger

    Roger Member Staff Member

    Yes, but as Gary was saying, 77mm is the general max size for most lenses, so even if you don't have one right now, you may want to plan for it.
     
    Roger, Oct 30, 2010
    #17
  18. mainstreet1997

    mainstreet1997 Member

    Haha I love how everyone around here is like "you might not have one yet but you will" :p. Actually I do, I believe my Tamaron 10-24 is a 77mm lens. ; Ive actually been shopping for step up/step down rings so I can use my expocap on all my lenses. ;


    Another ND question. Looking on BH and Amazon I see ND filters with "0.6" and "0.9" what does that mean? Don't see much with 4x or 8x.
     
    mainstreet1997, Oct 30, 2010
    #18
  19. Roger

    Roger Member Staff Member

    0.3 = 2 stop (2x)
    0.6 = 4 stop (4x)
    0.9 = 8 stop (8x)
     
    Roger, Oct 30, 2010
    #19
  20. gary

    gary Member

    thanks roger,


    unfortunately katie, in photography, as in so many other things, there are no standard descriptives, so that everyone would know what they were talking about.
     
    gary, Oct 30, 2010
    #20
Page 1 of 3

Share This Page