I recently got an older DSLR-camera with a nice set of lenses, but still know little about photography. I'd like to experiment with high-speed (or just timed right) photography to take pictures of popping balloons, objects dropping in paint, lightning and such. Looking at the code and hardware at photoduino.com, that shouldn't be too difficult. (once I figure out settings on the camera :))
I wouldn't mind playing a bit with the background as well. My idea is using a few high-powered RGB-leds as flash and a white background.
I'm not sure about a few things though.
On one side the pictures require a very short exposure time and analogwrite isn't analog at all on the other side.
With a long exposure time the camera will average each colour, but will PWM be fast enough with a short exposure time ?
Next thing I can't answer, what kind of leds (power/lumen) would be advisable if using PWM is a good idea at all ?
I'm thinking of 3-4 RGB-leds to get some variance and will probably only use'm indoors.
Photos like that are done by opening the shutter and using the flash to control the exposure. Your camera would be in "bulb" mode, and the flash would be waiting for the event. The Photoduino uses the standard camera remote control to open the shutter and hold it during the exposure - this requires proper settings on your camera, the remote is just an extension of your shutter button - wired remotes are usually $10 or less.
You can experiment with this technique without any special equipment if your camera has the bulb setting (time exposure) and you have a suitable subject. I have used this technique to photograph light trails from night flying model airplanes. It is also useful in a lightning storm at night, but not so useful for daytime lightning storms. The idea is to have the shutter open completely at the time of the flash, and avoid over-exposure due to ambient lighting - so this is typically done in the dark.
The flashing of an LED can be pretty quick, but not super bright, so you're going to probably need something else for really fast stuff, but LED should work for experiments. Should be easy to try - if you have an Arduino unit and some LEDs it should take about 30 minutes to wire up something simple and do some code for it. Get something that moves and just do some sample photos - you're going to want to do this a lot because there is a technique to it and you have to learn that. Your camera will make all the difference - I use a Sony Alpha 65, and I could wire up something and give this a shot.
This is a time exposure... maybe 10 seconds long I think - the trick is to capture what you want without over-exposing the rest of the frame. So, for these with the lights in the background I used a really small aperture. Just learn to play around with that stuff, and learn what you need to adjust when you see a particular problem. Like, when to increase the exposure time or instead, increase the aperture - both would fix the exposure but have different effects.
BTW, this is really a photography question, not really an Arduino question (yet) - you might want to read some of the popular photography blogs. There is a ton of information about doing time exposures for high speed captures, and also the low-speed technique I'm using.
Many of the example photos on the Photoduino site show really great technique aside from the high-speed techniques, so you're going to want to learn those. In many cases it seems to be standard "studio" lighting, just done at high speed - you can tell because the photos don't have the harsh shadows typically created by flashing from a single point. They also have proper exposure, good white balance, good focus and so on - that takes work (like, you're not going to be able to use auto-focus here). So, to produce good photos there's a lot more happening here than how to trigger the flash. Use this project to learn those techniques.
I knew I would need to learn more, apparently a lot more, but you made it a lot clearer..
One of the first things I really need is control over the lights in my room (to avoid walking in the dark) with my arduino. Using a dark room, long exposure and short flash indeed makes more sense.
Point is that I inherited the camera, a Fuji Finepix S3 and need to learn a lot about photography. Project is more or less intended to do that. Instead of walking around with a heavy camera,limited battery capacity and a tiny screen to watch results, it will give me the possibility to spend a complete afternoon, compare results on an 22inch screen almost instantly and lookup any info I need while learning/experimenting.
The pictures on the photoduinosite indeed look great and the lighting used gave me the idea of using high powered leds. Luckily I have loads of leds laying around and also a few high powered ones, so experimenting won't cost much. For me it was/is also hard to say what bright is in photography, even low power leds can look painfully bright, but I have no way of comparing it visually with a camera flash. If I understand you correct though, it should also be possible to open the shutter, use limited light for some time, trigger an electromagnet to drop a piece of metal and use the flash when it hits the soup/glass/whatever.
The camera has a flash inside and the set came with 2 extra flashes, so I'll be able to do a lot with those as well. It's a pity the tripod I already had at home isn't sturdy enough to support it but otherwise it's (as far as I can tell) a very complete set. It didn't have an remote, but I already found one for $5 on Ebay.
The site you mentioned is great, right after searching "arduino" an article on high speed photography and a lot of others popped up. There's still a lot I don't know that I'll have to learn it, but thanks for pointing my nose in the right direction !
It is a little old, but lucky for us, the laws of physics don't really change from year to year. The updates are only in the technology used after the physical fact of taking a picture is done. That process is mostly the same regardless of what sensor you're using - film or a digital CCD or whatever. So, that's why I say it's mostly a photography question. You have all the settings and features you will need to do this - most of the techniques for high speed photos date back to the 50s and 60s anyway. The only thing we've really gotten better at is synchronizing the flash and to a certain degree, not failing to capture the moment - a digital sensor can capture data that film would miss, allowing us to 'fix' the photo later, if the exposure was slightly off for example. I can't think of any interesting motion to capture at the moment or I'd set this up here in the house just to show you how easy it is. Really, you should be able to start experimenting with this technique right away, using manual flashes. At least that would help you start getting data about how to use your camera.
Amounts of light... tricky subject. LEDs look super bright to our eyes but that's because we get a continuous blast of light. A camera does not really work that way, it takes in a specific amount of light, controlled by the shutter, the aperture, and the amount of light available. So, you could flash the same LED in different ways to change the exposure or the amount of time captured, but there are going to be limits. For example, if you need a full tenth of a second of LED light to get correct exposures on your largest aperture, you are going to have to be happy with capturing that relatively lengthy time period, or get more LEDs - increasing the ISO generally just adds noise but you can try that too. You'll want to play around with some of this stuff before you go and buy anything. Get a feel for how your camera works, and how much light you need, then figure out a way to get that. It's an iterative process, and it probably will be years before you're shooting bullets hitting things. But when you're ready to do that, I'll be happy to shoot the objects for you
