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Step 8Adjusting the Camera Settings
Normally you would be triggering an external flash, while the shutter is open using a cable release with the camera in 'bulb' mode. Once the flash goes off, you let the shutter close. This requires the room to be darken because the shutter will be open for many seconds.
In this setup you can have the room lights on because the flash and shutter are triggered at the same time, and the exposure is set for 1/10,000th of a second.
Before we hook the camera up to the trigger circuit we first adjust it's settings, manually taking pictures until we get the exposure correct.
Mount your camera on a tripod and place a stationary test object right where the drop is going to land. Frame the test object, and adjust zoom to your liking. Use the macro setting if your camera is close enough to do so.
Keep in mind that you will most likely get milk splashed onto your camera and lens, so the Dollar Store glass plate should be placed in front of the lens to prevent this. If the glass plate is in front of the flash it may reflect back into the lens, causing unwanted glare.
Now take a test shot and revue how it turned out. If the shot isn't properly exposed adjust the exposure, flash and ISO until it is.
You can also adjust the shutter speed, but keep in mind that it's mostly the flash that's freezing the action. I set the shutter speed to 1/10000 of a second and left it alone.
On my A470 aperture override is not available. In its place is ND Filter State. ND stands for Neutral Density filter. Some cameras don't have an iris, but instead have a filter to adjust how much light enters the camera. If your camera has this instead of aperture override you won't have as much control over exposure because there are only three settings: [In], [Out] and [Off].
In this setup you can have the room lights on because the flash and shutter are triggered at the same time, and the exposure is set for 1/10,000th of a second.
Before we hook the camera up to the trigger circuit we first adjust it's settings, manually taking pictures until we get the exposure correct.
Mount your camera on a tripod and place a stationary test object right where the drop is going to land. Frame the test object, and adjust zoom to your liking. Use the macro setting if your camera is close enough to do so.
Keep in mind that you will most likely get milk splashed onto your camera and lens, so the Dollar Store glass plate should be placed in front of the lens to prevent this. If the glass plate is in front of the flash it may reflect back into the lens, causing unwanted glare.
Now take a test shot and revue how it turned out. If the shot isn't properly exposed adjust the exposure, flash and ISO until it is.
You can also adjust the shutter speed, but keep in mind that it's mostly the flash that's freezing the action. I set the shutter speed to 1/10000 of a second and left it alone.
On my A470 aperture override is not available. In its place is ND Filter State. ND stands for Neutral Density filter. Some cameras don't have an iris, but instead have a filter to adjust how much light enters the camera. If your camera has this instead of aperture override you won't have as much control over exposure because there are only three settings: [In], [Out] and [Off].
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thanks for explanations. I think I couldn't explain well what I was thinking. Between laser device and photodiode there is a line that laser goes on. when milk drop go across this line it cuts laser beam and all system start work and camera shoot the photo. This line between laser device and photo diode is 3 or 4 inches away from the plate that is full of milk. When paint drop cut laser beam it pass 3-4 inches to reach the plate.This takes a very short time like 10 milisecond. And camera is programmed to take photo 10 milisecond after the laser beam cut.
My airgun bullet has speed nearly 1000 f/s. so the distance between laser beam and target must be far more than 3-4 inches. That is the distance that I must find. Thanks again for your explanations
From what I’ve read, sound triggers are the best way to get the shot you’re after.
Here’s a link discussing that: http://nitpicker.blogspot.com/2007/03/how-to-trigger-strobe-for-photographing.html
The pellet may be moving too fast to even trigger my circuit. I have the laser as close to the dropper bottle as possible, so the drop is moving slowly when it passes through the beam.
With even a cheap green laser (i.e. one rated <1mW) you could probably trigger a setup like this or similar from half a mile away (although then you come up against beam divergence - the way the beam diameter expands with distance). Red lasers don't have quite the range and haven't nearly got the brightness of green - though only to our somewhat biased eyes.
In any case, you shouldn't have an issue with distances on the scales you'll be dealing with.
Plus, the photodiode is quite sensitive. The spec's on it say it's tuned to blue light, with red dropping the sensitivity to more than half. But blasting it with a red laser more than makes up for that.
For a quick range test, I bounced the beam off of 2 mirrors and through two panes of glass, covering a distance of about 75 feet. Instead of the small red dot it normally produced, it was spread out about a centimeter (half inch). The circuit still worked perfectly.
Let us know how things work out!