Is this related to how high speed videography works? I'm curious to learn more about high speed video cameras like the ones made by Phantom work. Does anybody have any good resources I can take a look at?
frankieeder
I'm not super familiar with high-speed cameras specifically, but I'm sure the most relevant topics/limitations would be shutter speed and sensor readout. Theoretically you could shoot as at many frames per second as you want, but your shutter speed (speed of the shutter opening and closing) would need to be on the same order of magnitude. I know my consumer camera can shoot at a shutter speed of 1/8000th for still images, but I imagine there might be more physical limitations as this shutter actuation would need to happen thousands of times per second instead of just once every few seconds, i.e. that's gotta be some super special shutter for it to be able to last for that many actuations. Also, taking more frames per second obviously increases the amount of data you need to write per second, which in practice is very difficult because images already contain so much data.
cornrow-kenny
How does the long exposure mentioned here relate to high-speed photography? I'm a little confused since it seems like some of the example photographs were shot using short exposures since I don't see a lot of motion blur.
mishywangiepie
@cornrow-kenny I think it refers to a later section on long exposure of moving objects in 3 slides, and the "high-speed" descriptor referring to the objects that are moving at high speed
sandykzhang
Is this related to why we tend to use a flash when taking portraits in a studio setting, rather than using a more continuous light source?
fywu85
I think the use of flash as opposed to continuous light source has more to do with energy consumption. Light only matters when the shutter is open, so there is no reason to provide light outside the duration of when the shutter is open.
nathanpetreaca
To cornrow-kenny and others, the way they took these images is as follows. They got a camera and put it in a dark room with the scene as shown. They then opened the shutter and kept it open. So basically, the camera is collecting photons already, but the way they configured the camera here is such that it is very insensitive, so it needs a strong amount of light to produce the image. So, when they flash a very strong and quick strobe light at the scene, that light that bounces from the scene because of the strobe light, is the only light that is picked up by the sensor because the sensor is very insensitive.
To capture the bullet in midair, they simply configure the light to flash a certain amount of time after the gun is shot so that the bullet has travelled from the muzzle right in front of the camera when the flash of light occurs.
Just watch this video and all will be clear https://www.youtube.com/watch?v=SMoIKNZGyf8 .
nathanpetreaca
The reason for doing this is because the strobe light is much much faster than a mechanical shutter.
x-fa19
In lecture, it was mentioned that the timing of the gunshot was key to getting these photos to capture the right moment. I'm not too familiar with photography; is timing of taking photos more of a trial-and-error process, or can it be automated? Or is it a mix of both?
moridin22
I think that it depends on what exactly you are taking a photograph of. In the case of taking a picture of a gunshot, trial and error would probably take a huge number of shots to capture the right moment, so it's worth the overhead work of setting up a timing method to make sure everything is synchronized.
xiaoyankang
Here's an interesting guide to high-speed photography. "Points to remember: shoot in dark room; small aperture; manually focus; flashes"
https://digital-photography-school.com/high-speed-photography-fundamentals/
Is this related to how high speed videography works? I'm curious to learn more about high speed video cameras like the ones made by Phantom work. Does anybody have any good resources I can take a look at?
I'm not super familiar with high-speed cameras specifically, but I'm sure the most relevant topics/limitations would be shutter speed and sensor readout. Theoretically you could shoot as at many frames per second as you want, but your shutter speed (speed of the shutter opening and closing) would need to be on the same order of magnitude. I know my consumer camera can shoot at a shutter speed of 1/8000th for still images, but I imagine there might be more physical limitations as this shutter actuation would need to happen thousands of times per second instead of just once every few seconds, i.e. that's gotta be some super special shutter for it to be able to last for that many actuations. Also, taking more frames per second obviously increases the amount of data you need to write per second, which in practice is very difficult because images already contain so much data.
How does the long exposure mentioned here relate to high-speed photography? I'm a little confused since it seems like some of the example photographs were shot using short exposures since I don't see a lot of motion blur.
@cornrow-kenny I think it refers to a later section on long exposure of moving objects in 3 slides, and the "high-speed" descriptor referring to the objects that are moving at high speed
Is this related to why we tend to use a flash when taking portraits in a studio setting, rather than using a more continuous light source?
I think the use of flash as opposed to continuous light source has more to do with energy consumption. Light only matters when the shutter is open, so there is no reason to provide light outside the duration of when the shutter is open.
To cornrow-kenny and others, the way they took these images is as follows. They got a camera and put it in a dark room with the scene as shown. They then opened the shutter and kept it open. So basically, the camera is collecting photons already, but the way they configured the camera here is such that it is very insensitive, so it needs a strong amount of light to produce the image. So, when they flash a very strong and quick strobe light at the scene, that light that bounces from the scene because of the strobe light, is the only light that is picked up by the sensor because the sensor is very insensitive.
To capture the bullet in midair, they simply configure the light to flash a certain amount of time after the gun is shot so that the bullet has travelled from the muzzle right in front of the camera when the flash of light occurs.
Just watch this video and all will be clear https://www.youtube.com/watch?v=SMoIKNZGyf8 .
The reason for doing this is because the strobe light is much much faster than a mechanical shutter.
In lecture, it was mentioned that the timing of the gunshot was key to getting these photos to capture the right moment. I'm not too familiar with photography; is timing of taking photos more of a trial-and-error process, or can it be automated? Or is it a mix of both?
I think that it depends on what exactly you are taking a photograph of. In the case of taking a picture of a gunshot, trial and error would probably take a huge number of shots to capture the right moment, so it's worth the overhead work of setting up a timing method to make sure everything is synchronized.
Here's an interesting guide to high-speed photography. "Points to remember: shoot in dark room; small aperture; manually focus; flashes" https://digital-photography-school.com/high-speed-photography-fundamentals/