PhotosbyKev

Using a Mumford Time machine and a ballistic sensor it is relatively easy to capture the flight of a 0.177 air gun pellet going through objects.

The timing on this was planned to make sure the pellet was completely out of the image so a multipler of 8 was used on the Time machine so the pellet was long gone. The internal pressure in the Red Bull can has caused the top to fail.

A light bulb captured just as an air gun pellet exits the bulb on the left hand side. Two Canon 580Ex flashguns were used to illuminate the event and they were set at 1/128 of full power.

A 5 second exposure was taken which allowed me time to manually fire a flashgun behind the cigarette to get the smoke trail and then fire an air gun pellet through the cigarette, this event was captured by a flashgun on 1/128 full power which was triggered by a Mumford time machine.

A playing card being struck by an air gun pellet. In order to get the spray on this image I taped a small teabag to the rear of the card that I had filled with talcum powder.

Two 580Ex flashguns were used both on the right hand side of the camera about 150mm from the playing card. They were manually set to 1/128 of full power to get the very short flash duration required. To trigger the flashguns at the right time the ballistic sensor attached to a Mumford time machine was used.

1 second exposure @ f22 iso 200 using a Canon 40D and 100mm macro lens.

This image is taken with two Canon 580Ex flashguns placed about 100mm from the candle. The main flashgun is triggered directly from the Time Machine and the second gun triggered wirelessly from the first gun.

Both guns were set to 1/128 of full power and a multiplier of 2 was used to trigger the flashguns when the pellet was 200mm (8″) from the end of the sensor tube. The candle was positioned about 7″ from the sensor so the event would be captured after the pellet had passed through the candle.

The ballistic sensor also measures the velocity of the pellet and in this instance it was travelling at 433 feet/sec, that’s approximately 130m/sec. During the flash duration of 1/35,000sec the pellet will have travelled almost 4 millimetres and is just visible at the edge of the spray.

An exposure of 1 second @ f22 iso 100 was used in a darkened room. The camera shutter was manually triggered just before firing the air gun. The 1 second exposure has captured the flame as it was dragged away from the candle wick by the pressure wave from the pellet and the initial impact.

This image is of a small cherry tomato being struck by a 0.177 air gun pellet travelling at 433 fps.

Again two Canon 580Ex flashguns were used to capture the event. One in front of the tomato and one behind to backlight the spray of the juice. Both guns were set on 1/64 of full power and zoomed to 70mm to increase the light on the subject.

Exposure was 1 second @ f11 iso 200 taken in a darkened room. Taken on a Canon EOS 40D and 100mm macro lens. Interesting to see the spray travelling backwards from the entry point of the pellet.

A recent stop motion animation test on a clockwork mechanism.

500 high-resolution full frame images taken at 1 millisecond intervals using a high speed flash setup and a Mumford Time Machine.

500 photographs triggered by a photodiode across one of the moving arms. Each frame was incremented by 0.001 second delay. So this represents 0.5 second of movement but took a couple of hours to shoot.

This is an updated attempt at this animation, the original can be seen here.

A recent stop motion animation test on a clockwork mechanism.

500 high-resolution full frame images taken at 2 millisecond intervals using a high speed flash setup and a Mumford Time Machine.

500 photographs triggered by a photodiode across one of the moving arms. Each frame was incremented by 0.002 second delay. So this represents 1 second of movement but took a couple of hours to shoot.

There is something odd happening to the clockwork which I haven’t figured out yet, the timing appears to be accurate looking at the out of focus gear wheel on the left but the central mechanism is very irregular. Perhaps I need to shoot at even smaller timing increments.

This animation has been reshot at 1 millisecond intervals and can be viewed here

EOS 40D and 100mm macro lens lit using a 580Ex and 550Ex flashgun on 1/128 of full power placed a few inches away from the clockwork. Each frame 2″ @ f22 iso 200 in a darkened room

Lighting setup

Th optical trigger can just be seen clipped to the right hand side of the mechanism

I was curious as to what I could freeze using my Canon 580Ex flashgun so I had a play in the lab using a photodiode and scope to measure the flash duration of the flashgun (averaged value over 4 flashes) at the various power output settings. The results were:

1/1 power = 1/1000 second
1/2 power = 1/2000
1/4 power = 1/4000
1/8 power = 1/9000
1/16 power = 1/15000
1/32 power = 1/21000
1/64 power = 1/30000
1/128 power = 1/35000

“What does this mean” I hear you scream, closely followed by “wtf has this to do with photography”?

Well the answer is, in order to freeze the movement of a fast moving subject a photographer will, at first, try to freeze the movement using a fast shutter speed. The maximum shutter speed on a good DSLR is around 1/8000 second but in order to use this speed you either need:

very, very strong lighting,
a wide open aperture and/or
a high ISO setting

An alternative is to use a flashgun(s) and by reducing the power output of the flashgun the flash durations can be as short as 1/35000 second for the 580Ex flashgun. If the flash is placed very close to the subject a small aperture and low ISO setting can also be used.

Various experiments with High Speed Flash can be viewed here