Cokin A121F User Manual
Main applications:
ND filters allow:
Several density types:
ND filters come in many strengths or different levels
of tint (densities) for fine-tuning exposures
as well as various rates of transition:
1.
A larger aperture and consequently a smaller depth of field which helps, for instance, separate
(isolate) subjects from their background (which becomes blurred). The lens operates then in the range
of its best optical perfomance, say around f/5.6 to f/8, rather than a very small opening where
diffraction or other optical artifacts might become an issue.
of its best optical perfomance, say around f/5.6 to f/8, rather than a very small opening where
diffraction or other optical artifacts might become an issue.
2.
A much slower shutter speed to be used at reasonable aperture, to record movement (create sense
of motion) in subjects such as waterfalls, clouds, cars, seas…
3.
A decrease of the effective ISO of high speed film (above ISO 400) to make it possible to be used
outdoor in bright situations.
4.
A proper use of cine and video cameras (which have fixed shutter speeds) to film subjects such as
snow, sand or other bright scenes causing so oftenly overexposure issues.
5.
A closer focus and larger depth of field in flash macro photography without overpowering the image.
ND2 reduces amount of light to 50%
ND4 reduces amount of light to 25%
ND8 reduces amount of light to 12.5%
ND4 reduces amount of light to 25%
ND8 reduces amount of light to 12.5%
or in other words
ND-2 absorbs 1 f-stop of light
ND-4 absorbs 2 f-stops of light
ND-8 absorbs 3 f-stops of light
Depending on the manufacturer, there are
different namings to these strengths or levels
(one is the decimal logarithm of the other)
different namings to these strengths or levels
(one is the decimal logarithm of the other)
or in other words
ND2 = ND 0.3
ND4 = ND 0.6
ND8 = ND 0.9
Photo : L. Sierpe
Photo : L. Sierpe
COKIN ND4
COKIN ND8
Photo : L. Sierpe
COKIN ND2