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 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.
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.
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.
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.
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.”
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.
Elite team member Marc Margulies putting on a Tiffen Glimmer Glass filter
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.
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.
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.
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?
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