Cokin WX125F Datasheet download pdf (Page 21)

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INFRARED FILTER

UV-N

Sky Neutral

230 UV-Y 231 Skylight 1B 232

FLW 036

Gradual

FLD

139

FLD 046

Gradual

FLW

138

UV & SKYLIGHT FILTERS

WORKING BEYOND THE VISIBLE

Auto-focus and exposure meters are here completely

unnecessary!

Think about shifting the focus forward to the infrared mark of

your lens (if there is one!) and adjust the aperture as much as

possible.

For the exposure, taking the indexes on the technical brochure

of the ﬁlm as a starting point – in digital, push the sensitivity

but not beyond 400 ISO – measure the exposure manually, with

the ﬁlter in place; take a number of shots (2 to 4 stops over the

calculated exposure) by increments of one stop; do preliminary

tests before starting to shoot...

Finally, work preferably with a tripod to avoid all fuzziness lin-

ked to prolonged exposures!

Working with infrared imagery is quite demanding. Among other

issues, the ﬁlm must be loaded in complete darkness and must

be kept cool at all times, numerous tries are necessary, and the

results can be unpredictable. But they are worth the effort put

into them!

In digital, the effort goes into the time spent in postproduction!

Time-consuming but so captiviting!!

Basically, one opens the ﬁle, the image being in brown-red

tones; change it over to black and white by completely desa-

turating the colour image (avoid using greyscale); ﬁnally adjust

the light/colour setting until obtaining the desired result. And

practice makes perfect, as usual, for creation of images that are

out of the ordinary, even magical.

FLUO FILTERS

These

ﬁlters are in fact ultraviolet blockers, light rays whose wavelength is below 400 nm and to which our

eyes are not at all (or just barely) sensitive. But that significantly affects films as well as photo or video

sensors. It results in a characteristic prevailing blue, particularly evident at high altitudes – where the UV rays are very

intense – at sea level, and in aerial photography.

•

These ﬁlters visibly reduce atmospheric haze at far distances and cut

down this dominant blue. They only intercept UV rays and therefore

in theory add no colouration of their own. In practice, this is ge-

nerally not the case!

•

The neutral UV N (230) really is neutral: the Skylight 1A

(232) introduces a dominant rose and makes the images a

little warmer, without completely attaining the effect of

an 81A, for example, while the UV Y (231), very light yellow,

diminishes the dominant blue very often associated with

UV rays. These three ﬁlters improve the sheen of images

and none of them requires exposure consideration.

You should know that the COKIN CR39

filter has the inherent

capacity to screen out UV light – the cutoff point is at 400 nm

– so it is not necessary to add one of these 3 filters if you are

already using any other Z-PRO filter.

• UV Sky Neutral : chromatically neutral

anti-UV filter. + 0 stop

• UV Y :

presents a very light yellow tone,

ideal for diminishing dominant blues.

0 stop

• Skylight 1B : presents a rose tone,

makes colours a little warmer in shady

or cloudy weather. + 0 stop

Fluorescent

tubes – which come in various models

and which therefore can wear out

to varying degrees – emit a discontinuous spectrum of light

characterized by a very strong proportion of green. With a film

balanced for daylight, this translates into a very characteristic

prevailing greenish tint that, while it adds a certain look to

images that some people appreciate, can be very difficult to

remove completely ...

•

In the absence of colour compensating filters (CC, see page

39), perfectly adapted to this type of lighting, a more simple

solution consists in opting for filters designed specifically for

use with fluorescent lighting and which exist in 2 types: FLD for

films balanced for daylight,

and FLW for those that compensate

for

artificial light. Combining a colour warmth conversion action

with a correction of the specific dominant tint, these filters

strike a balance as best they can among the range of situations

that can present themselves.

When one is confronted with mixed lighting – and this is often the case - we

can either resort to tedious preparation (filtering the windows or the floors

one by one with special gels), or choosing a specific graduated filters, FLD

or FLW, depending on the type of film used. The upper part of these filters

is intended to work with “neon” lighting, and the bottom part is neutral.

Correctly positioned, they constitute a solution as rapid as it is elegant and

easy to implement for solving problems created by many of these mixed

lighting situations.

• FLW : for films balanced for artificial light. + 0 stop

• Gradual FLW :

for ﬁlms balanced for artiﬁcial light and in case

of mixed sources. +

1 stop

• FLD :

for ﬁlms balanced for daylight, for use preferably with

mixed sources. +

2/3 stop

• Gradual FLD :

: for ﬁlms balanced for daylight and with mixed

sources. +

2/3 stop

Beyond

the spectrum of light visible to the human eye – which is roughly between 400 and

700 nm – one finds infrared light, which we can perceive by way of special films, black

and white as well as colour, and today, via digital sensors, at least those without anti-IR filters (or with

removable ones).

•

In order for these different media to fully record the effect of the inner spectrum of infrared light, one needs a ﬁlter that

blocks the visible spectrum and lets infrared light pass through. That is precisely what the 007 ﬁlter does, in the same way

as the Kodak® Wratten

89B ﬁlter.

•

The resulting image will vary considerably depending on the ﬁlm or sensor used.

In black and white with a professional ﬁlm such as Kodak’s® “High Speed Infrared”, the image taken with COKIN

007 ﬁlter will have a characteristic aspect: blue skies will become almost black and vegetation will take on various

shades of white, giving it a surreal appearance.

In colour, with an emulsion such as the Kodak

”Ektachrome Professional Infrared EIR”, the image will present absolutely

surrealistic tones, varying between magentas and blues with a yellow ﬁlter (001), shifting over to yellows and

reds with an orange (002) or red (003) ﬁlter, and

reaching its maximum effect with the IR ﬁlter (007).

The infrared ﬁlter is an endless source of research

and inspiration.

The arrival of digital cameras has further sustained

the keen interest in creative infrared photography.

The basic effect is close to that obtained in black and

white ﬁlm, but the possibilities of post-processing

open the door to virtually limitless creative possibilities.

Once you have assured yourself that your sensor can

record the inner spectrum of infrared light, think of

carrying out a speciﬁc white balance beforehand with

the IR ﬁlter in place for best results.

Infrared :

blocks all visible light

up to 650 nm, allows 50% of

light to 720 nm and more than

90% of the infrared beyond.

6 stops

SPECIAL FILTERS

ULTRA VIOLET – FLUO – INFRARED

For those who wish

to permanently protect the

front part of their lenses from dust,

scratches and various projectiles, COKIN

also offers protection ﬁlters of a very high

quality, in mineral or organic glass depending

on the model, in standard or thin (“slim”) screw

mounting, in over 20 diameters from 25 to 86 mm

and in 7 different types: three UV (standard, neutral

or multi-layer coating), and four Skylights, 1A and

1B (each available as standard or multi-layer

coating). Now you can satisfy all your

needs and ensure the long life of your

precious optical components.

Infrared

(89B)

007

FILTER 046

> Photography V. Diamy

FILTER 007

> Photography José Joaquin Castro

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Cokin WX125F Datasheet Page 21

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