Capturing whitewater - plein air and photos, plus DIY ND filter

Today's painting was apropos to my plan, as promised, photos of moving water taken with an inexpensive, homemade ND filter.

Low Water Riffles - 12x12"
pastel on black cardstock
© S.Johnson

Titled for the fact that our river is at record lows for this time of the year, thanks to a lower than average snowpack.  The result is more river rocks exposed and lots more whitewater.  Made for a somewhat complex and busy painting, but as always, the process was valuable.  New location for this painting - near Rotary Park and north of the downtown area.

Now, on to the photography part of the post.  As much as I enjoyed doing the paintings along Cascade, I was almost more excited to indulge in a photography bender using this ND filter I mentioned, so I carried my tripod, both camera lenses and the streamlined plein air get-up on our Friday hike, specifically so I could take photos of the falls we'd seen the week before.

For those who aren't familiar with this particular piece of equipment, this Wikipedia entry explains it better than I can.  When photographing moving water in normal sunlight conditions, you need an ND filter in order to obtain the soft water effect:

Limestone Steps
1/50 sec @ f/22 - no filter

Limestone Steps, Cascade Creek
0.5 sec @ f/22 + filter

Maybe not everyone likes the soft water effect in photos, but I love it.  Always have.

As you can see, even stopped down to the smallest aperture (like other gauges, the larger the f-stop #, the smaller the aperture; for my 18-70mm lens, f/22 is as small as it gets), the shutter speed is still to fast to produce that effect.

Enter the ND filter.  Why make your own?  Because they can be pricy - most run $50+.  On the outdoor forum I read, someone posted about making one that cost less than $10, and I was all about that.

Here's all you need:

L to R:  cement, step-up ring for your camera lens ($3.47 - amazon.com),
duct tape, piece of welding mask glass, Shade 5 (~$6.00, from local welding supply shop)
It's shown on this log because I bought the tape and cement on my way out of town, and assembled it in the RV at the campsite.

Here's what the filter looks like before I added the tape.  You can't tell from this photo, but the glass is actually green - it's like looking through a dark pair of Ray Ban wayfarer sunglasses :).  It screws right on to the end of my lens:

Do-it-yourself Neutral Density filter

I used it to shoot Engine Falls on our hike up the trail, but after I'd finished, I discovered a better compositional location, and taking advantage of a cloud covering the sun on the way back, I slipped back up the spur trail and shot this photo without the filter - I won't use it if I don't have to!

Engine Falls
f/22 @ 0.625 sec

Here are some other favorites, all shot on Saturday when it was too cloudy to paint, at various locations along the trail and right where Hwy 550 crosses the creek, and all with the filter, at a variety of shutter speeds (all chosen by the camera's internal meter - I always shoot Aperture Priority for these types of shots):

f/22 @ 0.4 sec

f/22 @ 0.5 sec

f/20 @ 3.6 sec.

f/20 @ 6 seconds

Here's a shot from our campsite late in the afternoon, also without the filter:

Orange lichen and the green pool
f/22 @ 0.4 sec

As someone who appreciates others sharing their "how-to" and "DIY" tips and techniques, I wanted to do the same for anyone reading who might be interested, or knows anyone else that is.  Another thing important to note:  as this is not technically a "neutral" density filter, but a green one, the images will have a strong green tint to them.  Shoot in RAW format, and use any editing software to adjust the hue and temperature as needed, and it's not an issue.