Tag: Long Exposure

Rock Brook iPhone "Long Exposure” (not really)

I took the day off to relax a bit. My son Shaan came home early from school -- he has a study break for exams this week -- so I took him out for lunch at the One53 restaurant in Rocky Hill. We talked about college, school, and world history. I then persuaded him to come with me to the Rock Brook in Skillman. I wanted to test out an iPhone app I recently discovered called Slow Shutter Cam. It's for creating long exposure images.

The app creates these images, not by changing the aperture and exposure, but by cleverly combining multiple exposures using an image algorithm. The effect of long exposure is created by blending each of the captured images.

After capture, I made some quick adjustments in Photogene for iOS. The photo above was edited on my iPhone 6 with some tweaks in Adobe Photoshop Lightroom.

The Rock Brook in December

I shot these as part of one of my Arcanum Cohort assignments to level up. The Rock Brooks looks very stark in winter compared to spring.

While I wanted to try the technique of using the polarizing filter as shown in Lisa Bethany's video, I don't own a polarizing filter. But I do own a 9 stop Neutral Density (ND) filter which I've used a few times before.

I watched a lot of videos (about 30 minutes) in the Grand Library but few of the techniques were useful given my limitations of time and weather. In the future, I will need to choose my videos more wisely.

It rained most of this week and all day yesterday so the brooks and streams in my town are once again flowing with water. I revisited the Rock Brook along Hollow Road in Skillman, near the foot of the Sourland Mountain Range. A month ago the brook was dry with only a few pools of stagnant water.

I set up my tripod on the very edge of the brook and focused and composed my shot. I set the camera to aperture priority mode and set the lens aperture of the Nikkor 35mm f/1.8 lens to f/8. My Nikon D5100 has an APS-C sized sensor. It's smaller than a 35mm sized sensor which means that the FOV is smaller. The images will appear as though they are cropped. The Nikon APS-C crop factor is 1.5. That means that my 35mm at f/8 has the field of view and aperture of a 52mm (35 x 1.5) lens at f/12 (8 x 1.5).

Skillman, New Jersey, Rock Brook

I took note of the shutter speed and entered the values into an application called PhotoPils. PhotoPils helps computes the proper exposure time when using ND filters. Once I had the proper exposure computed I turned off the auto-focus on the lens, set the camera to manual, dial in the correct exposure, set my camera to use the remote-trigger, and fired off a few shots.

Camera shake is the enemy. To help reduce that I made sure to use the Live View feature on my Nikon. It looks up the mirror before exposing the sensor. This helps reduce vibration in the mirror box.

Despite having some decent sunlight it was very cold outside this morning. The air temperature was about 2ºC (~36ºF). I suffered some mild frostbite.

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Rock Brook

I drove to 360 Grandview around 8:30 AM and walked around for an hour enjoying the peace and quiet. The recent rains added some "life" to the stream so I used my Neutral Density filter and a trip to get some "white water" photos. But these photos were not taken at the Rock Mill Preserve. These were taken along Hollow Road just north of Camp Meeting Avenue. I pulled the car over, grab my camera, ND filter, and tripod, and walked down to the stream.

I spent about 30 minutes working on composition and lighting. At first, I used my Nikkor 35mm f/1.8 but realized that the Nikkor 18-55 f/3.5-5.6 would give me more choices. I had to run back to the car and get it.

Computing the exposure values for the use of an ND filter can be complicated. The Hoya NDx400 is a 9 stop -- "Big Stopper" -- ND filter. It's nearly impossible to focus once the filter is on the lens. Ed Velez told me about the PhotoPills app. This was my first time using it.

Nikon D5100 + Nikon 35 mm f/1.8 @ (35 mm, f/11, ISO100), Copyright 2014-05-04 Khürt L. Williams

The app helped me easily calculate equivalent exposures with the filter in the available light. For example, without the filter, the exposure for the camera setting for correct exposure was at 1/13s at f/16. With the Hoya filter, the equivalent exposure was 17 seconds at f/16. I couldn't get 17 seconds on my D5100 I used 15 seconds or 20 seconds.

NOTE: The D5100 is a crop sensor -- APS-C -- camera. The full-frame equivalent of f/16 on APS-C is roughly f/10.33 which is approximately f/11. So I used an aperture of f/11 for these shots.

Nikon D5100 + Nikon 18-55 mm f/3.5-5.6 @ (18 mm, f/11, ISO100), Copyright 2014-05-04 Khürt L. Williams