Filtering

Bay Bulls River
(Focal length 18mm, Shutter: 1 second, Aperture: f22, Filter: ND 10).

For years I enjoyed photography with a 35mm SLR camera and worked more or less within the limits of the existing lens and what opportunity a polarizing filter could offer. I really didn’t experiment much with many different kinds of filters, mainly because it was expensive and time-consuming to conduct such experiments.

Sea Breath
(Focal length 55mm, Shutter: 2 second, Aperture: f16, Filter: ND8)

With film, there was always the initial outlay for film, the additional cost of developing and finally the week-long wait (unless you shelled out additional funds for quicker service) for the results, which might tell you that you had to go back and try again. Disheartening, to say the least. Expensive, too, for students on a budget.

With the DSLR, however, all of these constraints are removed. Taking two-dozen shots doesn’t cost me anything but time (and I supposed wear and tear on the camera, but that occurs in film photography, too). The developing time depends on how quickly I can dump the memory card and have a look at the results. If the results are less than stellar, I can head out again right away, if necessary.

Today I spent some time with a neutral density filter (ND, for short). The one I purchased has multiple stops, which means it gets lighter or darker, depending on where you set it. This allows me to adjust for varying light conditions.

What an ND filter does is basically cut down on the amount of light that gets into the camera. When there is less light getting in, you need to keep the shutter open for longer to let enough light in. When the shutter is open for longer, moving things blur.

The corollary of this is that without the filter, in situations with bright light or lots of reflecting light (ocean, snow, etc), it becomes impossible to keep the shutter open for long periods (if you WANT that blurred effect) without over-exposing the picture. Enter the ND filter. Today I took dozens of test shots, playing with the different shutter speeds. All this work was done with the Nikon D70, on either the manual setting or the shutter priority setting, ISO 320. (Not sure why it’s set on that. Must remember to change it!)

You can see the difference in the same spot of river, taken at different shutter speeds:

_DSC3981
(Focal length 70mm, Shutter: 1/1500, Aperture: f4.5) No filter.
_DSC3959
(Focal length 35mm, Shutter: 1/2 second, Aperture: f9.5) With filter.
_DSC3982
(Focal length 52mm, Shutter: 1/1.5s Aperture: f16) With filter.

Today’s shoot was more of a test run, to get a feel for the tool and to be able to deal with how my camera reacts to it when used in a critical situation (critical defined here as a time in which I care about the actual results of the shoot). Today was a day for experimentation without expectations and I’m pretty pleased with how it went.

A couple of notes:

  • when the filter was cranked up on blast, the camera had a hard time focussing. The work-around for this was either to manually focus or to make sure aperture and shutter speed were on manual, crank down the filter, half-press the shutter to focus, keeping the shutter half-depressed, crank back the filter to max and finish the shutter depression.
  • the above makes the remote shutter trickier to use. For that, go manual all the way.
  • Don’t try this without a tripod. It’s not worth it.
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5 Comments Add yours

  1. Risto says:

    Absolutely nice shots! I have done perhaps thousands here in these rapids in Finland http://www.hundredpics.1g.fi/kuvat/111220-espoo-lauttasaari-c2-IMG_8749.jpg

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