It is spring and a lot of the wild grass is long and golden. I began noticing this on my drives home from work in the late afternoon and I thought about the long grasses swaying in the late afternoon sun and what that would look like with a long exposure. So, Sunday I took a few hours and hiked around Balcones Canyonlands National Wildlife Refuge as I know there is a lot of tall grass and cactus out there. The sky was mostly clear and I thought that I would have a nice chance for warm golden-hour light on the grass.
I used a 10-stop ND filter attached to a 24-120mm zoom lens. I spent a lot of time around some cactus trying to get the right composition. I wanted the grass to sway in the wind and blur to gold with the cactus stable and in focus as it is too big to be very perturbed by the wind. I did not get much wind and I don’t think that my cactus compositions worked at all. But walking the paths I did see large areas of tall grass and I set about trying to come up with a composition.
In the picture below, I used a tree in the background in an attempt to anchor the picture against the motion blurred grass. The tree was also blowing in the wind a bit so there is a lot of motion blur there as well. But I did get the grass to do mostly what I wanted.
The above shot is a 20 second exposure at f/20 and ISO100 with the 10-stop ND filter. Very much longer and I would have risked over-exposing the sky. I was also careful to level the camera using the built-in leveling function.
The technique that I used for creating these photos was to first compose the picture, focus the lens, and determine exposure without the ND filter on the lens. There is not enough light through the ND filter to do any of this with the filter attached. I selected a very small aperture to get as long an exposure as possible. I set the camera to expose for the highlights to avoid blowing out the sky. I found that I could get a good exposure without clipping the highlights at f/20 and 1/50s shutter speed. I then multiplied 1/50s (or 0.02s) by 1000 to get the 20 second exposure with the 10-stop ND filter.
Tip: Stops are a measure of doubling or halving the light. In this case, I am using the shutter speed to control the amount of light reaching the sensor, so a stop is a doubling or halving of the time the shutter is open. A 1 stop filter would halve the amount of light coming into the lens and require you to double (multiply by 2^1) the time the shutter is open to get the same exposure. A 10 stop filter requires you to double the time the shutter is open 10 times or multiply by 2^10 (which can be rounded to 1000 for easy math). You can get an app to do this or use a calculator, but it is easy to just move the decimal three places to the right with a 10-stop filter.
As it got later, I headed back down the trail toward the parking lot and this took me over a slight ridge covered with long grass. I stopped here and thought about some compositions as the light was fantastic. The line of the ridge was too gradual to really capture from this vantage point, but there were some large rocks in the grass, so I decided to incorporate these rocks into a composition with the grass in the last light from the afternoon sun.
The wind wasn’t blowing very much, but the grass moved a little bit in the wind. I did dial the clarity slider down a bit in Lightroom to enhance the blur in the grass. I was really going for a sort of smooth golden blur, but there was not enough wind for that.
For the next picture I just turned around to face the other direction. There were more rocks and some interesting clouds in this direction. It was late enough that I was able to get a 30 second exposure and I did get a little wind on the grass. The sun light got around the lens hood and gave me some flare, which I don’t really mind.
This is my favorite photo of this outing. The foreground rock is large enough to hold interest and not be distracting and there are hints of other rocks hidden in the grass. The warm colors of the setting sun are fantastic, and there are some clouds to give the sky some character. I could have used a bit more wind.
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