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Diffusion for the Digital Age: The Use of Glass Filtration

This is our final blog topic on diffusion. We showed you how to use smoke to create a mood and an old style panty hose technique to diffuse and create a unique look. Now we will demonstrate the power of the glass filter. There are many manufacturers making diffusion filters. We will demo the ones that I use and their wonderful benefits. All of them have their place in the art of softening an image. Let’s start with one of my favorites.

Soft FX made by Tiffen

Soft FX made by Tiffen

 

Soft FX has small little dots laid onto the glass.  This diffusion works very well on a woman’s face, very cool for blooming the highlights, but on long lenses, you can sometimes see the dots on the glass and it gives away the ghost.
 

Tiffen Soft FX comparison

85mm Soft FX comparison

 

Filtration Rules

Typically, the rule of thumb is to use heavier diffusion when using a tighter lens and a lighter diffusion when going to a longer one, pretty much like the net being stretched looser or tighter. So for a 24mm, I would use a number 2 SFX. Then on the 50-85, I would use a number 1 SFX. For anything above a 100mm, I would use the number 1/2 SFX.

Black Pro-Mist made by Tiffen

 Black Pro-Mist made by Tiffen

 
The purpose of these filters is to soften but not flatten your image too much.  The Black Pro-Mist works very much like the Fogal Net in the way that it blooms the highlights but without losing contrast. It is very easy to cut through the filter and or the net to get that contrast back.
 

35mm Black Pro-Mist comparison

85mm Black Pro-Mist

 

Pro-Mist made by Tiffen

Pro-Mist made by Tiffen

 
Pro-Mist diffusion affects the contrast as well as blooming your highlights. I am not a big fan of this filtration, because it feels a little heavy handed.

35mm Pro-Mist comparison

85mm Pro-Mist comparison

 

Digital Diffusion made by Tiffen

Digital Diffusion

 
Tiffen Digital Diffusion is beautiful and works incredibly well on a woman’s skin.  It is my go to in that department.  Experiment on which levels you like. You can go as heavy as number 5 on the softening measure. The filtration range is from number ¼, ½, and 1 through 5.  I used this on the close-ups of Emma in the Hospital and the Boutique in “The Ticket.”
 

Emma’s closeup in the Hospital from “The Ticket”

Emma’s closeup in the Hospital from “The Ticket”

Emma’s closeup in the Boutique from “The Ticket”

Emma’s closeup in the Boutique from “The Ticket”

35mm Digital Diffusion comparison

85mm digital diffusion comparison

 

Glimmer Glass made by Tiffen

Glimmer Glass

 
This is a new diffusion for me. Tiffen came to me with Glimmer Glass when I was describing the effect that Po Chan wanted for the running sequence on “The Ticket.” She wanted the highlights to bloom with an aura around them, but the eyes to stay sharp. Tiffen sent me a full range to test for the shoot. Po and I settled on number 3 to pull off this beautiful effect. Another cool accident happened when we put it on the long lens, which was a number one. When we rotated the filter, we got an anamorphic like flare coming from headlights when Emma and Vince ran down the street.
 

Emma and Vince running

Elite team member Marc Margulies putting on a Tiffen Glimmer Glass filterElite team member Marc Margulies putting on a Tiffen Glimmer Glass filter

Blooming highlights

 Pier blooming highlights

35mm glimmer glass comparison

85mm Glimmer Glass comparison

 

Pitfalls of glass diffusion

The main pitfall with using glass filtration is the double reflection, flaring, and or milk out effect you get if the sun or a bright light hits your lens or a hot soft source will affect contrast. You have to be very careful when using strong backlight with glass, as well as smoke. These go hand in hand. Use a mattebox as well as an eyebrow for best results. The Master Cinema Series Mattebox works really well in handling the backlight flares. Notice the eyebrow has an extension to reach out of your shot and get that nasty flare.
 

Letus Master Cinema series Matte Box with eyebrow extension

Letus Master Cinema series Matte Box with eyebrow extension

 
Another way your image can get milked out and lose that beautiful contrast is with light coming from the side or 3/4 back. This again can be handled with side flaps on the mattebox to keep that from hitting the glass.
 

Letus Master Cinema series Matte Box with eyebrow extension and side flaps

Letus Master Cinema series Matte Box with eyebrow extension and side flaps

 
Using 2 or 3 pieces of glass in front of the lens is not always a good thing for sharpness.  People who stack NDs are playing with double reflection fire as well and taking the image out at the knees with softening in bad ways.  If you have to double and or triple stack your glass, make sure you have an ARF (Anti-Reflection Tray).  This device helps with multi-reflections caused with glass stacking.  Also, tape your filters together if you go over 3 pieces of glass. Any air or light getting in there will wreak havoc.
 

Letus Master Cinema Series Arf places 4X5 filtration at an angle

Letus Master Cinema Series Arf places 4X5 filtration at an angle

 
I would suggest getting a set of ND’s that go all the way up to 7 to 10 stops. Now you can use just one piece of glass to bring down your exposure where you want it and then diffuse with the other. I have found the Tiffen Water White ND filtration to be the best. However, that is just my opinion and based on personal preference. Now that all of these new cameras coming out have an effective ISO of 800 and above, Neutral Density is your friend to bring your exposure as well as your depth of field in a good place so that your image looks cinematic. Fader NDs seem very practical and quick to adjust, but sucking the life out of someone skin is usually not on my high list of things to do as a cinematographer. There is always the time and the place to polarize skin. On “The Greatest Game Ever Played,” I wanted everyone’s skin to have a pola quality, to feel period, matted. But this is definitely a look.
 

 
Next on the series of using filters, we will go into the world of polarization. Tests will also accompany this post. Stay tuned! Thank you to Danielle See, our model for the filter tests.
 

 
What types of glass diffusion do you use?

Author: Shane

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52 Comments

  1. Wow, extensive and super useful. Thanks for putting this together. It seems that one has to really know what they’re doing with some of the heavier diffusion. Great to hear what works for you. Thanks.

    Post a Reply
    • Not one of the best but probably the best free film making information that i have come across in my five years of film knowledge seeking. i have come across what you have written many times but NEVER WITH THE REFERENCE OF ACTUALLY HOLLYWOOD FILM FRAMES that a person him self had done. NEVER SEEN SOME ONE EXPLAIN IN SO MUCH CLARITY ..I HAVE NO WORDS .. MY BEST WISHES TO YOU SHANE!!

      Post a Reply
      • ATIQ John, these are the kind words that keep us inspired to continue to share. Thank you for these wonderful words

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  2. But I always thought to use lighter filtration on wide lens, cause you need to see all those details in wide shot. And heavier diffusion on woman’s skin will kill the wrinkles for sure if you need that effect. Does it make a sense?

    Post a Reply
    • Alex. Thanks for the comment and support. It depends on the look you’re going for. I usually go for heavier diffusion on a wide lens because a wider lens doesn’t compress the diffusion like a long lens would. So in order to make the diffusion more prominent on a wide shot you need a heavier set of diffusion on the lens. However if you want a sharper more detailed wide shot, then you should use less diffusion or none at all. Just creative choices.

      Post a Reply
  3. Thank you for sharing with us Shane. I am learning so much here. I have a question. I have noticed that with the many diferent diffusion filters on, the bokeh effect becomes more visable. If the aperature has not changed, is this also an effect of the diffusion filters? I love the look those filters give and cannot wait to get my own!

    Post a Reply
    • Sean. Thanks for the comment and support. On this test the aperture did not change, its the filtration affecting the highlights from the bokeh.

      Post a Reply
  4. Shane,

    Thank you for another awesome series of blogs!

    Questions: Some of my lenses can use rear filters could I use glass filters on the rear and avoid the pitfalls of using glass diffusion? Second if I were to net a a filter ring , how would having the net further from the the rear element effect the netting effect?

    Thank you,
    Bill

    Post a Reply
    • Bill Hamell. Thats a good idea, but I haven’t come across any glass diffusion that small. Having the net further from the rear element should have a less prominent effect. Try experimenting with different amounts of stretch on the net and placements to find what you like best. Thanks for the comment and support.

      Post a Reply
      • Shane,thank you for the knowledge! :)

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        • One word of extreme caution about using rear-mounted filters, particularly glass ones. The additional optical thickness at that point in the light train is very apt to throw off your lens’s focus scale.

          Bolex users may remember the advisory if their camera’s lens flange was set up for using behind-the-lens GEL filters (which are typically a LOT thinner than glass!) if you didn’t need filtration like ND, 85 &c, you should keep a clear or UV filter in the gel carrier so as not to throw off the focus calibration.

          The effect of additional optical thickness when using behind-the-lens filters shows up worst on wide-angle lenses. Wides, for a given aperture, have huge depth-of-field, but very little depth-of-focus (which is like depth-of-field, but on the camera, rather than the subject side of the lens). The two terms are NOT interchangeable. Contrariwise, for a given aperture, telephoto lenses have poor depth-of-field, but rather more depth-of-focus. Ask any camera technician, and they’ll tell you flange depth is much more critical to set for wide angle lenses.

          So if you’re using a behind-the-lens filter, especially with a wide-angle lens, and you start having phantom focus issues, look at your filter as being a likely culprit.

          GREAT advice, Shane! A most useful posting!

          Post a Reply
  5. Great article. The details are excellent.
    Being a director, it’s so very important to know what options are at my disposal in regards to the image I can create with my DP. These filters provide a subtle nuance to an image, and seeing them demo’d in this way lays out some of the high-end options quite nicely.

    Post a Reply
    • Chris. Thanks so much for the kind words and support.

      Post a Reply
  6. Awesome article and great example pics/video! Great way to differentiate the subtle differences when choosing glass filtration. Looking forward to future posts and learning more about how to get exactly what’s in my head into the frame!

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    • David. Thanks so much for the kind words and support.

      Post a Reply
  7. Ive found that for my Epic shoots that 1/8 and 1/4 BPM works well to lift th blacks slightly, bloom the highlights, and soften harder skin features. Great post Shane. Cheers!

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  8. Thanks Shane for sharing this stuff!

    I recently did a shot outside with a variable ND and got caught off guard by the light refracting between the two pieces of filter. I hadn’t noticed it do this before and wasn’t aware that it was washing out my image. Needless to say I lost a great take to cheap glass. I think I need to invest in some quality filters :)

    Post a Reply
  9. This is great stuff – I especially like the look of the glimmer glass.

    I think it’s a shame that Canon is the only manufacturer on the block that included and ND wheel in their Digital Cinema cams. I like cutting down light without putting all that glass in front of my lens.

    I notice these filters add a slight milky haze to the image. Is that something that can be worked out with color timing while still having the impact on skin tones and light sources?

    Post a Reply
    • Portillo. Thanks for the kind words and support. The milkiness can easily be taken out when color timing by adding contrast, and I find that it doesn’t impact the skin tones or sources when dialed in correctly. I use the right level of diffusion for the look I want then add some contact if necessary when coloring.The examples we shot exaggerate the milkiness due to the strong backlight.

      Post a Reply
  10. Thank you Shane for this post! I’ve been trying to achieve a less digital look out of my FS100, and I think I’m going to give the Digital Diffusion series a try. Thank you again for your words of wisdom!

    Aaron

    Post a Reply
    • Aaron. You are very welcome. Thanks for the kind words and support.

      Post a Reply
  11. Hi Shane, thanks for all the great info. I want to get your ND Filter Kit but B&H only has the 77mm Indie Plus HV Filter Kit in stock at the moment. I’m really keen in getting filters quickly. I’m shooting most of my stuff outside with a 5d on a 50mm 1.4 at f4 to f6. Do you think the Indie Plus HV Filter Kit will be to strong for my needs (I want to keep shutter speed at 1/50?) Thanks for your support :)

    Post a Reply
    • Carlos. Thanks for the kind words and support. The Tiffen HV ND kit will work great and is designed for HDSLR video. The level of ND you want to use depends on how much you light you are trying to cut. A .3 ND will reduce it by one stop, a .6 two stops, and so on. If you can’t find the kit you need on B&H give film tools a shot http://www.filmtools.com.

      Post a Reply
      • Thanks Shane! Filmtools doesn’t have it in stock as well at the moment! But I’ll find it somewhere. Here’s a rough ND calculation I found in a forum, it can be useful for someone…

        f22 (base exposure no ND)
        f16 (.3 ND)
        f11 (.6ND)
        f8 (.9ND)
        f5.6 (1.2ND)
        f4 (1.5ND)
        f2.8 (1.8ND)

        All the best!

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  12. Anyone know where you can rent Tiffen Digital Diffusion 2 in Los Angeles?

    Post a Reply
  13. Thanks for the awesome post. One question. I know you talked about stacking ND’s but does the same apply to a black pro mist? Can you even stack a black pro mist?

    Post a Reply
    • Kevin, not advisable to stack filtration, too much softening in not good way

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  14. I never understood what warming filters were for until recently when I was shooting a very pale midwesterner in afternoon sun outdoors about 3 o’clock. His skin was corpse-like grey through the LCD, but the Tiffen Warm-Soft F/X 1 gave him healthy, yet subtle looking skin tone and knocked back his wrinkles just enough to make him look distinguished. I love that filter.

    Post a Reply
  15. Hello Shane, thank you for all the wonderful input; you truly are a beacon for inspiration.
    There are a lot of filters mentioned here. Im curious about which one acts like the way video looks when shot through metal mesh?
    Similar to the results when holding your lens up to a screen door to shoot a hot sunny day.
    Thank you.

    Post a Reply
    • Vince Gortho. I would say a rear net is the closest to that. Thanks for the comment and support.

      Post a Reply
  16. Thanks for the extensive data, Shane.
    Have you encountered a filter that works magic with black and near-blacks, but (hopefully) doesn’t do too much to the highlights? Or even if you personally haven’t tested one, is there one you have heard of? Optimally I’d get it in 39 for the Leica M9, but larger is OK.

    Post a Reply
    • diane kaye, Tiffen’s digital diffusion very well in holding the blacks and not blooming the highlights

      Post a Reply
  17. Dear Shane,

    I just purchased a Blackmagic Cinema Camera 2.5K. I already have the Tiffen Indie filter kit with the Water White NDs (0.3-1.2), and want to purchase the IRND set too. However I would like to add a diffusion filter for my camera. I’m going to shoot a small feature film in RAW in a few weeks. Digital is too sharp for me, even more with the Speed Booster I bought for my camera. So I’d like to add something to make it more “film” like. However my story is basically takes places at night, visually it’s gritty, a dark city, with touches of Blade Runner lighting style. Several scenes will use a thin layer of smoke too. Because of this fact I’m seriously concerned which filter should I use, if I should use any at all. Could you give me some tips?

    Thanks so much!

    Post a Reply
    • therussian, smoke should do it for you. At night it is difficult to use diffusion filters, many double and triple reflections. I would use older glass with your camera and they will do most of the heavy lifting and your image will look more filmic. Also using the Dark Energy plug-in on After Effects will give you a texture that I did on Act of Valor. Hope this helps

      Post a Reply
  18. Great information and accompanying examples. Just in time to. I’m shopping for some new filters and your site helped me make a decision. Keep up the great work!

    Post a Reply
    • Oren Arieli, it is our pleasure on the Hurlblog. Thanks for the kind words and support

      Post a Reply
  19. Hi Shane!

    Thank you so much for taking your time to learn us these awesome tips and tricks, it means a lot for all of us!

    I have just placed my order on a Tiffen Glimmerglass 1 filter to use as a all round diffusion, do you think it was a good choice? I love what it does with the highlights, and the 1 strength will make it just pop without overdoing it, I hope?

    I just want to take away that harsh HD look from my Panasonic GH3 and give it a more soft and filmic feel.

    Post a Reply
    • Andre, that is a great choice as well as the Tiffen Black Satin. Love those as well. Does the same effect with the highlights but doesn’t mile out the mid tones as much

      Post a Reply
  20. Hey Shane! I had a question about your test and how it effects the overall image. Does the blooming from the lights behind your model effect the look on your model? Its great to see how the highlights are effected by the filtrations but I am wondering if the blooming is adding more to the effect of the filtration on her face. Did the filtration on the model react the same ways when you had the background light off?

    Post a Reply
    • Matt Maio, ha ha, I love that you ask this question. This was a cinematographer intern test. They had to take my notes and deliver a test the way I described. The young lad took it upon himself to put lights directly behind the model that influenced the diffusion filter. His penance will be re shooting all of this footage without that god damn light behind her head. Thank you for your patience. Yes the filter was influenced by the flaring lights. The softness would not be as extreme without that flare. But it does show that using diffusion is a dicey way to go sometimes because of all these outside influences that you cannot control.

      Post a Reply
  21. Your website is a great source of information. Thank you for sharing all the info. I learned so much.

    I have to admit that I find the rule that says to use thicker diffusion on longer lenses counterintuitive. If the filter has a pattern of dots (like for example a Soft FX or Black Diffusion) then when a longer lens is used, the spacing between those dots becomes greater, there is less dots per image area because the lens is looking through the filter at a narrower angle. Sort of a similar effect as shooting through a net fence in a foreground: when the lens is wide you can see the net and many of its cells, when the lens is longer it sees a smaller area of the net therefore the cells become much bigger and there is fewer of them in the frame, in addition they are more out of focus – the net fence often completely disappears. I am sure your rule is not based on just theory but instead on extensive tests and experience so I do trust you, but as mentioned above, I find the rule counterintuitive. Thanks again! Looking forward to reading your new posts!

    Post a Reply
    • Mat, I think I might have confused you, so sorry. If I am on a 100mm then I am using a 1/2 soft efx’s. If I am on a 35mm then I am using a 1 soft EFX’s and if I am on a 14mm then I am using a 2 Soft EFX’s. Thanks for sharing and pointing this out. I will change the post to say this.

      Post a Reply
      • Sorry Shane, just read my own comment again and it does not make sense. What I really meant to say was “… I find the rule that says to use thicker diffusion on WIDER lenses counterintuitive” (not on LONGER as I wrote by mistake). The rest of the comment is correct, the way I meant it. Sorry about the confusion and thanks again!

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  22. Two Tools for Creating More Cinematic Visuals, thank for the support

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  1. Cinefotografia - Diffusion for the Digital Age: The Use of Glass Filtration - [...] by Shane Hurlbut, ASC www.hurlbutvisuals.com 8 [...]
  2. The Complete Guide to Lens Filters (Part Two) | wolfcrow - […] Many of the effects of diffusion filters are subtle. Here’s a video by Shane Hurlbut on how to test …
  3. Two Tools for Creating More Cinematic Visuals - […] of the Black Pro Mist is the soft bloom of the highlights. Check out Shane’s full post on lens diffusion …

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