Cokin A Series Gradual Grey G2 Light ND4 Filter 67x67mm (A121M)

Progressive graduation from the middle to the top of the filter, same colour as121 but lower tone. Only ND4 gradual filter.

Recommended for lenses between 36 and 62mm in diameter with a focal length over 35mm. Cokin square filters fit into a holder and are attached to a lens via an adapter ring.

ND filters are among those tools which have become indispensable in today's digital technology. They offer the possibility to achieve otherwise unachievable results as they are the real sunglasses for your camera. Typically, ND filters are used when shooting in bright light such as strong sunshine, snowy mountains or on white beaches. ND's filter the entire visible spectrum evenly, allowing light reduction - reducing the amount of light reaching the CCD, film or tape, without altering the relative spectral distribution of the energy, thus without influence on colour temperature, colour balance or contrast. For this reason they are often referred to as neutral or grey filters.

• A larger aperture and consequently a smaller depth of field which helps separate subjects from their background (which becomes blurred.) The lens operates then in the range of its best optical performance, say around f/5.6 to f/8 rather than a very small opening where diffraction or other optical artifacts might become an issue.
• A much slower shutter speed to be used at reasonable aperture, to record movement in subjects such as waterfalls, clouds, cars, seascapes etc.
• A decrease of the effective ISO of high speed film (above ISO 400) to make it possible to be used outdoors in bright situations.
• A proper use of cine and video cameras (which have fixed shutter speeds) to film subjects such as snow, sand or other bright scenes which often cause over exposure issues.
• A closer focus and larger depth of filed in flash macro photography without overpowering the image.