Lower Marble Creek falls is located in Merwin Park right by Merwin Dam on of course, Lake Merwin.
Hike difficulty is easy and perfectly fine for children. The only part that would be sketchy for them is the climb down to the water. Luckily there is a lookout point with a picnic table that they can be occupied at while you slip below to snap the shot. If they get hot after the hike, there is a marked off swimming area in the lake right by the parking lot.
Once parked at the only parking area, follow the asphalt path around to the far end of the park. Once you hit the gravel it is roughly under 1/2 mile to the falls. Enjoy the view of the lake during the quick, flat hike!
Once you get to the viewpoint, settle the not so adventurous ones at the table and prepare to get dirty. You can go around the small wooden fence and see a small path made by others. It is made of roots, rocks, and little steps carved out of the dirt. My safest way to get down paths like this without tripping and falling into the water is basically slide down. Be prepared to slide on some loose dirt and rocks.
On hotter days there is actually a rope in one of the trees that you can swing into the lagoon on!
Once your at your viewpoint its time to break out the gear! Camera on tripod, position your angles.
You won’t get full sunlight into the cove, but I still put on a polarizing filter . This will cut down the light reflecting on the water and you can actually see into the water, just like your polarized sunglasses.
Ken Rockwell has a great article on the uses of filters and when to use them. http://www.kenrockwell.com/tech/filters.htm
Now you can slow down the water. For this, I usually dial in my desired shutter speed and then I will adjust my aperture for the proper exposure.
Check out my quick overview of shutter speed and aperture if you need a refresher.
If you still can’t get the shutter speed you desire with the aperture you want, this is when ND filters come in handy. ND filters are dark pieces of glass or plastic that cover your lens, making the harsh light darker to your camera’s sensor. I have shot 30 second exposures in board daylight stacking these. I prefer the Cokin style stacking system because I shoot with multiple lenses with multiple diameters. If you only use one lens or all your lenses are the same size, you can get an adjustable filter that will screw into the front of your lens. Just be careful with these ones, most of the cheaper ones available turn your shots purple.
After cutting the light to your sensor using the filters, you can take long shots and still capture all the light in the shot.
Make sure to take your time and have fun while figuring out which lens and filters work best for you!