I need to be flashed. Automatically.

November 17, 2006 8:55 AM

How can I automate a series of photographs using two digital cameras and a set of lights?

I am doing scientific photography for thousands of objects. I need to build a setup involving two cameras, one with a ring light, several light sources, and a computer. I need to automate the sequence of photographs and lights. For example, the sequence might go like: 1) two of the lights come on and Camera 1 takes a picture 2) the two lights turn off and Camera 2 takes a photograph with the ring light, 3) a third light comes on and Camera 2 takes another picture, 4) the third light turns off, a fourth light turns on and Camera 2 takes a final picture. All of these images need to be captured to a computer with a suitable set of file names as quickly as possible so I can make it through the objects in a reasonable amount of time.

I am considering using Canon 400D cameras and I have seen programs like DSLR Remote Pro that can automate the cameras and the capturing. However, I am unsure how to automate the lights, whether this software will help control the ring lights, or if there is better software out there for this purpose. Are there any camera or computer geeks out there that can help me out with any suggestions?

posted by Tallguy to computers & internet (10 comments total)

Oh, and in addition to enduring gratitude I am happy to acknowledge you in a scientific paper. If that's not motivation, what is?
posted by Tallguy at 8:56 AM on November 17, 2006

Are you starting completely from scratch here? Ie, buying cameras and lights? Or are there any constraints on what's going to be used for lights?

Before I suggest anything I do have one comment - whatever solution you use probably should not turn lights ON but turn lights OFF. Almost all lighting solutions change color temperature as they warm up, and it sounds like you want a consistent result across all your shots. So what you should to to minimize any changes is have a system where all those lights are on until just before the shot is taken, at which point the ones you don't want to use cycle off, then on again as soon as the shot is completed.

My first thought for a solution for you was the number of complicated christmas light displays we saw a flurry of videos of last year. The cheapest solution available then was about $250 if I recall correctly and would control 8 channels of power, more than enough for your needs. A quick surf around turned up Control the Show, which includes mention that he'd be willing to do things for other people. Given that he did his own hardware odds are decent you could get a more customizable and cheaper solution, at least from a hardware perspective.

I'm going to go look for some of the other solutions I remember reading about - perhaps more later.
posted by phearlez at 9:51 AM on November 17, 2006

I've only got the vaguest outline of an idea here, but I think X10 might be the kernel of a solution. You can use this to control lights.

There are some digital cameras that can be controlled by an infrared remote. If you can also hook up an infrared emitter to your X10 controller, and learn the factory remote's codes, you could emit them on cue as part of an X10 script.

Here's a page listing camera control software.

I've never tried any of this. I'd stay open to other options, and spend some time on X10 message boards or talking with vendors to get a read on whether it's worth attempting.
posted by adamrice at 10:34 AM on November 17, 2006

X10 isn't great technology even for home lighting control and for something like this, where you don't need the remote signaling, you are probably better off using relays wired to some sort of controller (it could even be the parallel port).

It's been a while since I looked at it, but I thought people liked LabView for automating experimental data acquisition. I'm pretty sure they have image acquisition modules. It looks a little expensive, but should at least give you a benchmark to work from as you look for cheaper solutions.
posted by Good Brain at 10:57 AM on November 17, 2006

So far nothing has been purchased. And other than knowing I need about a 10 MP camera and need to get certain shots with certain lighting conditions, the rest is completely open.
posted by Tallguy at 11:01 AM on November 17, 2006

How's your scripting ability? I'll presume you can hack at something or can co-opt someone who can. Given that-

Here's a writeup of someone's project to do remote power management and a link to the $70 piece of hardware that will control 8 relays. More than enough for your quantity of lights. From the look of their sample perl script you could do this in a shell script - tripping a relay seems to be as simple as sending a few characters to a serial port. Looks like Some Assembly Required, however.

Alternately, here's a USB device that will control 16 items. At just under $500 it may be more money but the sheet claims their website has some sample VB code, if that's your forte. If your camera solution has some sort of API then it likely will also have some facility for VB control

I am presuming you're a windows shop.

There's this site, Phidgets, which seems to be targeted somewhat at researchers and might have a user community willing to help you with your issue. Looks like their relay gadgets that fit your bill are around $100.
posted by phearlez at 11:44 AM on November 17, 2006

This will be Windows based, and I am comfortable doing some programming. On the other-hand, I am hoping to develop instructions for others to follow, so the more "out of the box" this is the better. Thanks for the suggestions so far!
posted by Tallguy at 12:36 PM on November 17, 2006

In issue four of Brick Journal, there is an article about a guy using the Lego Mindstorms robotics system to control cameras to shoot a 3D timelapse of a plant growing. In his case, just the Lego motors were sufficient, in yours, you'd need to use relays for the mindstorms system to operate the lights. (Relays are not part of the system - you'd connect them yourself)

You could also look into "home automation" for ways and products for making your computer control lights.
posted by -harlequin- at 1:04 PM on November 17, 2006

phearlez writes "Almost all lighting solutions change color temperature as they warm up, and it sounds like you want a consistent result across all your shots."

Second this, if possible you're better off with flashes than lights. Not only will the lights change depending on how warm they are they also will change with use (generally get warmer with age).

Cooler too.
posted by Mitheral at 1:55 PM on November 17, 2006

If the computer interface is up to it, the computer could adjust a dimmer until the light matches the target reading of a light sensor. I imagine the colour temp has a strong, if not exact correlation with minute differences in brightness, if so then even a simple light sensor can measure - no need to measure spectra or anything complex like that.
posted by -harlequin- at 3:39 PM on November 17, 2006