One of the most popular accessories that are carried by serious photographers is the neutral density filter or better still a variable neutral density filter. A neutral density filter is one that stops the amount of light that reaches the camera sensor. They are called neutral because they stop light of all wave-length without any preference. So basically one can call them as sunglasses for your camera. It allows a user to use a longer shutter speed and achieve special effects in broad day light without the risk of overexposure. For example waterfall photography.The newest baby in the line of neutral density filters is the Tiffen Variable ND filters.
Variable neutral density filters can be screwed on to the front part of the lens using the slender thread mechanism. The front of the filter can be rotated which stops an increasing amount of light. In operation they are very similar to how an user would use a circular polarizer. This dialing adjustment feature eliminates the need for carrying several filters of different thickness. Usually these filters come in thickness or f-stops of 1, 2, 3 and so on. With a variable neutral density filter one can just turn it in a dialing motion and achieve the desired f-stop.
Typical “X” effect of variable neutral density
Like polarizers, specially with wide angle lenses, if you go beyond the maximum stop you will get that typical “X” mark effect on your photos. This is a normal phenomenon, as well as limitation of Variable Neutral Density filters.
Tiffen Variable ND filters comes in different sizes, including 77mm and 82mm. These are two of the largest lens diameters and should appeal to users of premium glasses. They provide 2 to 8 stops in a dialing motion. Wide angle lenses often create a problem of vignetting. To counter vignetting these filters are made extremely thin at only 9mm. They should allow for lesser vignetting problems and that should ensure better image quality at wider f-stops. However, in spite of the great quality of the glass and the minimum thickness some vignetting can happen depending upon the type of lens being used and the particular aperture settings.
Tiffen 82 mm VND & Canon EF 16-35mm f/2.8 L II – vignette
On our test, it showed no sign of vignette at the 16mm end while using with Canon EF 16-35mm f/2.8 L II without any UV filter attached.
@16mm with only 82mm Tiffen VND Attached
However, when attached on top of a UV or similar it shows some vignette at 16mm end. At around 19-20mm and beyond the problem disappears.
@16mm with Both UV & 82mm Tiffen VND Attached
On tele zoom like EF 70-200mm lens there is no such issue. Again full frame cameras tend to suffer more from the problem at lower f/stops compared to crop bodies.
The ability to use slower shutter speeds at wider apertures is one of the major advantages of using a variable neutral density filter and the Tiffen 82/77 mm VND makes it elegantly simple. ND filters with higher grades are very dark, may results autofocus difficulty. However, with VND you can focus easily at lower stop settings, then turn back to higher stops later.
Exposure f/7.1, 1 Sec, ISO 50, EOS 5D Mk III, 16-35 f/2.8 L II, Tiffen 82mm VND
With this filter on one can capture beautiful dramatic effects of a stream or waterfall, experiment with faster ISO, capture fine bokeh with a wider aperture in broad daylight and do very much every other thing that a photographer would hesitate to do in broad daylight.
Below is a nice Comparison video on Polariod vs Genus vs Lightcraft vs Tiffen vs Singh-Ray vs Heliopan Variable ND Filters
Tiffen uses premium quality glass in their filters and the 77 and 82mm VND filters are no exception. They come with Tiffen’s ColorCore™ technology and are backed by ten years warranty which should make them a companion for many interesting assignments. Warranty apart this expensive piece of glass is vulnerable to bad use as such it needs to be always taken care of if one intends to use it for a long time. It is prone to scratches, exposure to sunlight for long duration and drops which can damage it permanently.
Tiffen VND available at Amazon