Waterfall

Nikon D7000, 44mm (18-55), 3 sec., f/29, ISO 100, on-camera filter, adjusted and cropped

Yesterday was the final in-class session of my fall Photography course. As usual, the last non-online meet was optional, and as nobody who showed up needed to get caught up on anything, we spent the time having some fun.

The main activity was a set of light painting experiments I’ll post next week. But after class I was still in a picture-taking mood so I decided to try a new filter I bought awhile back.

The main idea behind neutral density filters (other than protection for expensive lenses) is to reduce the amount of light getting into the camera without affecting the color or image quality. The new toy in this case was a Hoya 52mm 3-400 variable density filter.

Variable density filters can be adjusted to let in more or less light. The minimum setting for this one lets in 1/3 of the light that would otherwise get through the lens, the approximate equivalent of 1.5 stops. At the opposite end of the scale the filter screens down to 1/400 of the light, around nine stops.

The photo at the top of this post shows the filter near maximum strength. The ISO is down as far as it would go and the aperture closed up as tight as it would go. The result is not much light getting through and not much sensitivity to record what does get through. That’s how I got away with a three second exposure, which otherwise in bright sunlight would have over-exposed the shot so badly that I would have gotten nothing but an empty white frame.

At this speed the water (the only moving subject in the shot) turns into a hazy blur. Compare the long exposure to something closer to normal speeds:

Nikon D7000, 44mm (18-55), 1/125, f/5.6, ISO 100, on-camera filter, adjusted

Turning the filter down to its minimum allowed me to speed up the shutter and freeze the flowing water. Though the result is a great deal more “realistic” (i.e. more like what you’d perceive if you were actually looking at the scene), it’s arguably not as interesting to look at. The composition is  more chaotic, not as smooth as the longer exposure that records the general flow rather than individual drops.