Which UV Filter should I use?

I'm going to be shooting in a mountainous area and possibly UV haze might be an issue.

I asked the camera rental place if they had any UV filters and they've come back with a mixed bag of what they have in stock;

UV2E

UV17

UV16

HAZE 2a

SKY 1A

Not sure of the manufacturers, though I think Tiffen features promenantly.

I only want to take one.

Having no experience of these filters, and not knowing what the subtle difference is between them all........

Can anyone advise?

Yours,

Tom Townend, Cinematographer/London.

Take the 2A- it will absorb all light at 400nm and below, and eliminate any inconsistencies in color cast that UV may otherwise impart to the image. We have long been making combination effect filters, like our Pro-Mist, to custom order with the 2A included, for Steven Poster. He discovered years ago that UV light, although not visible to the eye, can vary significantly in its effect on camera from day to day and even from hour to hour.

As for the other filters on your list, the 2E absorbs even more, into the visible, and is overkill and will impart a slightly stronger pale yellow tint; the -16 and -17 transmit 13.5% and 3% at 400nm, respectively, so they are not quite as strong as the 2A; and the Sky transmits 54.5% at 400nm, and also has a pink tint- primarily a home-photographer's way to get better skin tones outdoors, but not what you want.

Hope all goes well!

Ira Tiffen VP,R&D

The Tiffen Company, LLC Hauppauge, NY 631-273-2500 x1220

Thanks Ira. As definative answers go - that's a good 'un.

Tom Townend, Cinematographer/London.

Ira,

If shooting in high UV environments and using an 85 filter does it absorb the UV negating the need for a UV Filter ? If so how "effective" are they at this task. I also assume a polariser is an effective filter for UV as well ?

-- Tom Gleeson D.O.P.

Sydney Australia

Tom,

Additionally, the scattered UV that accumulates with distance, especially at high altitude, will be diminished, allowing somewhat more distant detail to show; a polarizer would further reduce polarized reflected glare from dust and water particles in the atmosphere. The pol absorbs some UV, but not enough to justify its use alone, in your situation.

Ira Tiffen VP,

R&D The Tiffen Company, LLC Hauppauge, NY 631-273-2500 x1220

Ira,

Do any of your standard filters like the 85B come with some UV filtration added? Isn't one of the functions of the LLD filter to filter excess UV from pulling the 85B?

I was always under the impression that the 85B filter had a UV filter built-in, which is why just substituting a warming filter like a Coral 5 might not give you the same UV protection.

David Mullen Cinematographer / L.A.

David,

You have often explained filter-related things so well, I expect you know much of this. The 85B is one of many Wratten-designated filters that had their color characteristics defined long ago according to various film-related color-sensitivity requirements. Although the 85 has a mired shift of 131, it is not strictly speaking just a color temperature corrector. It is actually salmon-colored instead of the more beige-toned color filter that would be called for by a color temperature shift alone. It was originally created to match the actual tungsten-film color sensitivity to daylight, and is not just a "generic" color temperature adjuster.

As such, it was determined that the film was more greatly affected by UV light than could be tolerated, so the transmission curve for the 85B was tailored to pass through very little UV light, in effect the equivalent of what you term a "UV filter built-in."

The LL-D (Low-Light Daylight)filter, as developed in the late '80's by Ed Ortman (formerly Kodak's chief test cinematographer), and myself, was based on Ed's observation that much of the effect of a conversion filter to accommodate tungsten film to daylight was due to the absorption of UV. The rest of the LL-D spectral curve serves as a means to further tweak the color rendition while minimizing the amount of light absorbed. This is why the LL-D allows, after color timing, the virtually identical color rendition as if you had used an 85B, but without requiring any exposure compensation.

You are also correct in stating that Coral filters do not absorb the same amount of UV, even in the densities that approximate the effect of an 85B. Corals were originally developed to maintain a certain visual color reference, especially to allow adjustment through the day as the sun moved in the sky.

Ira Tiffen VP, R&D The Tiffen Company, LLC Hauppauge, NY 631-273-2500 x1220

Tom,

An 85 transmits about 6% of light at 400nm; an 85B about 1%. So, individually, they both make very good UV light absorbers. Especially since they absorb much greater amounts of UV light when compared to the amount absorbed in the visible region. On the other hand, polarizers, which generally transmit about 10% or so, do not make good UV absorbers. The reason is that they do not absorb an appreciable amount of UV light in a significantly greater proportion than the amount of light absorbed in the visible region. When you compensate the typical 1-2/3 stop, you are effectively increasing the amount of all light coming through in the proportion each wavelength has to the overall. In a standard photographic polarizer, there is not a much-reduced transmission in the near UV compared to the visible, so UV is not cut in much greater proportion to the rest of the spectrum. Which is why we and others offer a UV-Pol combination.

Ira Tiffen VP,

R&D The Tiffen Company, LLC Hauppauge, NY 631-273-2500 x1220

Ira,

......not to beat this to death, but then an 85B/Pola (which I have) will do just fine for most work in absorbing UV, correct? At high altitudes or long lenses, perhaps using a 2A would work better.

all best,

Al Satterwhite DP/LA

I guess my question to Ira is: how exactly is a UV filter made? If the 85B does a good job of cutting UV, is this because the dyes or pigments that are used to create the 85B naturally also counteract UV -- or is something added to the mix when creating the 85B filter (as opposed to the Coral 5, let's say) that helps eliminate UV?

What about the Decamired filters then? Do they have the same UV filtration component as the 85B? What about ND filters? When shooting daylight-balanced stocks outdoors, should we be using UV filters as well as ND filters? Which filters do you make have a UV filter also designed into them, as opposed to being a special order item?

David Mullen Cinematographer / L.A.

David,

Lots of questions!

Like dyes and pigments, there are a variety of materials that have the ability to transmit well in the visible region, but not in the UV. The 85B curve, as defined by Kodak, requires a certain amount of UV absorption that demands that such UV-attenuating materials be added to the filter formulation. However, the other types, such as Corals, ND's, and Decamireds do not have such a requirement, so they do not have the equivalent ability to absorb UV, unless made-to-order to do so, which can be readily done. We have not printed our filter glass catalog in some time, although I revised it last year, and have a digital version of it. I may decide to put this on our web site, if interest is sufficient, but so far I only use it for individual specification requests. In it, it is clear by looking at the spectral curves which filters absorb UV. A lot of them do. A great source for similar information is the Kodak Wratten publication "Photographic Filters Handbook," CAT 152 8108. It also has tons of other useful data. If you find that UV is causing a problem, then you would certainly want to filter it out on a regular basis in situations where the problem occurs.

Ira Tiffen VP,

R&D The Tiffen Company, LLC Hauppauge, NY 631-273-2500 x1220

Al,

The 85BPol should do a fine job of reducing UV light, although the addition of a 2A would be a marginal improvement. This stuff is so subjective- a reliable test for determining "suitable vs. ideal vs. unsuitable" hasn't come to my attention as yet.

BTW, Steven Gladstone suggested that UV also could refer to "Uninspired Video"- something that should be filtered out at all costs ;-)

Ira Tiffen VP, R&D The Tiffen Company, LLC Hauppauge, NY 631-273-2500 x1220

Just to follow on....

What about the "partial" 85's...ie., the 81B and 81C? How is their UV performance?

Mark Schlicher

Cinematographer/videographer film/hdtv/beta/dv nashville.tn.usa

At 400nm:

81a transmits 65%

81b transmits 58%

81c transmits 49%

81d transmits 44%

81ef transmits 35%

85 transmits 6%

85b transmits 1%

85c transmits 15%

Not sure what the SPF numbers are.

Anders Uhl

Cinematographer ICG, New York