Photo Journal

Photo Journal

4/10/03 (2:30-5:00 PM)

This session we planned our project and discussed possible setups in order to obtain the film of water that would fit our requirements and be reproducible. First, we tried drilling many holes in an aluminum pipe and running water through it, but this did not produce the desired results. We also tried running water over a pane of glass, but the result was not easy to reproduce and glass presented safety issues that frankly weren't worth trouble. Finally, we sawed a tiny slit down the length of the pipe. Sure enough, this gave us our desired result and we got our "wall of water".

Spring Break!

4/22/03 (1-2:30 PM)

Now that we have a method of creating our subject, we began working on our setup. We successfully arranged the pellet gun, pipe, tank, flash unit, sound trigger and pellet trap in a working setup (see methods and setup). An apple 2+ computer and interface box was used to specify the flash unit delay. We did photograph today. Instead we just observed the pellet in order to roughly determine the delay needed.

4/24/03 (2:30-5:00 PM)

Our first photo session. Our efforts to visually locate the pellet failed earlier so we took a more scientific approach to estimate the expected delay. We used the average speed of a pellet shot from that specific gun (determined earlier), the speed of sound, the distance of gun to subject, and the distance from gun to trigger and DVAT equations to do this. Our approximation was about a 4-5ms delay. This delay was fine tuned throughout the session in order to obtain the desired results. We were specifically looking for a shot of the pellet right as it hits the water today. This is as close as we could get.

4/28/03 (9-9:45 AM)

We experimented with multiple flash units this sessions. It took a while to setup, so we did not have much time for actual photography. Unfortunately both the pictures we got were horribly overexposed and all the colors blended together into a pink blur. Here is an example:

4/29/03 (1-2:30 PM)

This session we abandoned the multiple flash idea and continued on with a single flash. We also added a wide-angle fresnel lens to the flash unit to further disperse the light and produce even more evenly lit photographs. We got most of our best shots at a delay time of ~4.5 ms. We also tried another shooting angle to find out if we could observe this phenomenon better from a different view. We got a lot more contrast in this set of photos, so the details are much more sharp. Here are some great examples of the sharp detail.

5/1/03 (3-5:00 PM)

Today we continued with single flash photography of this high speed event. There was unexplained variability in our delay time though and took extra time figure a new delay in order to capture the pellet hitting the water. We found the new delay to be ~5.2ms ( almost a full ms more than the previous sessions in the exact same scenario)

5/8/03 (2:30-5:00PM)

In order to obtain a more up close and detailed view of this phenomenon, we used a Nikon D1 and a telephoto lens for this photo shoot. This camera had a much higher resolution and the telephoto lens allowed us to get very close to our subject. We also decided to photograph the pellet exiting the water this time instead of entering in order to get a more complete understanding of this phenomenon. The only problem is that we got a green shade to most of our pictures, but some of them had a blue tint. We do not know how either color got into our photographs. Fortunately, since we are looking at these photos analytically this discoloring had not effect on us.