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Hardware

Digital Cameras As Web Cams? 16

Posted by Cliff from the low-FPS-web-fun dept.
A not-so Anonymous Coward asks: "I've got a spiffy Canon Digital Elph camera, and have been wondering if I can control it from my PC - that, is can I trigger it to take a picture remotely via the USB interface? If so, it seems a logical next step to turn it into a very (very) nice Web cam for stills at a fairly low frame rate. 1600x1200x24 bit. Also, I'd love to try my hand at digital astro-photography (put it on a telescope that is). Seems to me there ought to be some way for me to control it thru the USB again. Anyone with good leads/info on how to hack a Canon digital camera? Seems a worthy hack to me." Some cameras have command line utilities that can be used in scripts to do this. I know Kodak-compatible cameras can do this via ks or the DIGITA [?] scripting language, however I'm not so sure about Canon's Elph series. This also might not be too hard a capability to hack into gPhoto.
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Digital Cameras As Web Cams? More

Digital Cameras As Web Cams?

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  • Hey, cool! First post...

    But seriously....

    I did a quick scan of Deja and came up with this [deja.com], so it's sorta possible. That might give you a good start.

    But, really, at the price of the Digital Elph, why not just go get a nice dedicated webcam?

  • kodak (Score:3)

    by po_boy ( 69692 ) on Friday December 15, 2000 @11:06AM (#555960)
    I did this with my kodak DC280 and a cron job, but I had to shut it off after Jason got tired of the flash going off in the office every minute. I think I used gphoto, but I can't remember. Here [mooresystems.com] is an example of Jason getting flashed. I can't imagine why it bothered him.
  • man, where do you work? Screw working, i want to setup an apartment in that warehouse of an office. That place rocks.
    ------------------------
  • I've been looking at a new camera/web cam from Dlink. It will do 1024x768 on the camera and has 8 meg of onboard memory. It's usb and I wish I could find someone that has one of these to talk to them. It sells on dlink's site for $149.00 http://www.dlink.com/products/usb/dsc350/
  • It was when I used to work for handshake.com (AKA simplydone.com, AKA sdbs.net)

    It's a wharehouse in Marina del Rey, CA. It was kinda loud, but pretty cool building.

  • Yup (Score:1)

    by CMonk ( 20789 )
    I did that while I worked for the University. Check out:
    http://ScienceVIEW.Berkeley.EDU/view/

    It looks as though it has fallen into disrepair since I left. It took several months of photos (one minute interval) before it died. Kodak DC240, transfered via USB with gphoto, a cron job and a bit of help from perl. So, if gphoto supports your Elph than everything should be fairly simple.

    The relevant code:
    my $gphoto_text = `$gphoto -p /timelapse/$mon-$mday-$year/$time.jpg`;
    $gphoto_text =~ /\(\#\s(\d+)\)/;
    `$gphoto -d $1`;
  • Turn off the flash!
  • I use an Olympus D400Z [olympusamerica.com], which can be controlled via serial port. I use the program photopc [average.org], written by Eugene Crosser, which runs under a number of Unix variants. According to the readme
    This is a library and a command-line frontend to manipulate digital

    still cameras based on Fujitsu chipset and Sierra Imaging firmware. The
    program is known to work with Agfa, Epson, Olympus, Sanyo and Nikon (at
    least CoolPix 900, but not CoolPix 600!) cameras.
    You can indeed write scripts to regularly take a photo and download it from the camera. Good stuff!

  • Astro Photography (Score:3)

    by Bryan Andersen ( 16514 ) on Friday December 15, 2000 @12:50PM (#555967) Homepage

    For using it for astro photography you will need to be able to control the shutter speed. Many of the cheeper digital camers don't allow this. I don't know if yours allows shutter speed control or not. I own a Nikon 990 which allown me to do long exposures, up to 60 seconds if I hold the shutter button down. Unfortunatly it starts to show significant dark current problem on any photograph over 10 seconds long. It even shows some on 8 second shots. Another problem you will run into is the CCD chip in the camera has a color mask built in. This gives it color ability, but it also reduces the amount of light going to each resolveable pixel, typically 1/3rd to 1/4th. This means image times are atleast 3 to 4 times longer than with a BW CCD for a color shot. It also causes color effects as the image is sampled at different spots for each color. One can't get by the time issue for color astro work. However one can get around the color sampling at differnt spots. Astronomers use BW CCD cameras and color wheels, then take one shot each for red, gree, and blue. For good measure most astro photographers will also take a straight BW shot to. Another thing is the resolution the image's pizels are sampled at. Most consumer digital camers use 8 to 12 bit analog to digital converters in them. For astronomy you need as many bits as possible Many astro cameras are now at 16 bits.

    There are cameras specially made for astronomy. Unfortunatly their prices are astronimical in relation to regular consumer cameras. SBIG [sbig.com] is a major maker of astro camers for amatures and profesionals. It's a volume issue, plus these cameras have special coolers to help control and reduce dark current. The increased sampling resolution also helps jack the price up.

    You can do some limited astro work with consumer digital cameras. It's mainly limited to very bright objects like the moon and sun. Note if photographing the sun, only use proper sun filters made for looking at the sun. Any telescope or camera lense can and likely will intensify the light into dangerous eye dammaging levels.

  • Gphoto already has the capibility to tell the camera to take a picture (although not all cameras are created equally) and download it to your pc. It may be possible to do it command-line with gphoto v1 but certainly with the new gphoto v2 framework it should be easy enough to do it.

    Keep in mind that compact flash has a limited lifetime compared to other backing store so you may use up your cf quickly. Also, I believe the flash bulb in a camera has a short lifetime too.

  • Webcam: Yes, but not yet; Astrophoto: Not well (Score:3)

    by rjsjr ( 105611 ) on Friday December 15, 2000 @01:36PM (#555969) Homepage

    I can sympathize with what you are trying to do, as I've tried both uses with my Nikon Coolpix 950. The short answer is both are possible, but it isn't likely to be easy to get what you want out of the setup. Once drivers are available, you should be able to use your digital camera as a webcam fairly effectively, though you may have issues with autofocus, flash, and other camera-only adjustments. For astrophotography, it isn't likely you'll be able to get worthwhile images with the Elph, but I've included a few links on how to get started.

    Digial Camera Webcams

    Digital cameras defintely produce a much more compelling image than a typical webcam. I have a 3Com HomeConnect (a pretty good quality webcam) and it looks just awful compared to my Nikon N950 (not just resolution, but also trueness of color, CCD noise, and sensitivity). The main limitations are that you can't usually take mini-movies or fast sequences, some key functions are often only controllable on camera (for instance auto-focus and flash), and you'll need a power cord for the camera if you don't want to drain the batteries very quickly.

    The easiest way to control the camera from a linux box is with Scott Fritzinger's GPL'd gphoto [gphoto.com] program. gphoto allows basic control of a variety of cameras [gphoto.org] through serial or USB connection (and supports both interactive and commmand line modes - add a bit of perl and cron and you can do all sorts of fun things). Its still under development, however, and unfortunately doesn't currently support the Digital Elph (PowerShot S100) [powershot.com] to my knowledge. I'm not sure how involved it would be to write a USB Elph driver for it, but you can check out the site if you feel up to it.

    Digital Cameras and CCD Astrophotography

    With astrophotography, you are getting into a rather specialized and involved use of CCD devices and generally speaking, it takes a good bit of expertise and dollars to get good results. You don't mention what you are looking to capture or what existing equipment you have, so I'll point out some of the basics and you can research further from these. FWIW, I'm not by any means an expert here, but I've been looking to jump in, so I'm seeing the same issues.

    While there are limited exceptions, CCD astrophotography generally requires the use of specialized equipment. Your Canon Digital Elph doesn't have the required sensitivity (its equivalent to ISO 100 film), ability to take long exposures, long and fast enough lenses, or adapters for telescope mounting. While its possible to use a barn door tracker [hiwaay.net] or equitorial tracking camera mount with the Elph, the results aren't likely to be worth the effort.

    If you really get interested in astrophotography, you'll probably want to pony up for a specialized system like those built by Celestron [celestron.com] and SBIG [sbig.com]. These are highly sensitive, small array CCD cameras with specialized cooling and software for high gain operation. Add a high quality telescope, equitorial tracking mount, and related accessories, and you are talking about no small dollar commitment. Also, you'll need a lot of time and patience to find and capture accurately really good photos. I'd like to try CCD astrophotography out, but will be playing with 35mm (add a T mount and a Meade ETX and you can get started for under $1000) until I decide I'm really committed and move to a less light polluted neighborhood.

    Sky & Telescope [skyandtelescope.com] has a pretty good guide on where to start [skyandtelescope.com]. Some good introductions to astrophotgraphy are:

    Have fun, RJS

  • One of my friends was using his digicam as a webcam for a while. One of the problems that he had with it was that the camera would turn itself off after a period of time without human interaction and cease to work. It may be worth checking if your camera has this "feature". I've had very good success using a camcorder as a webcam. My last semester in college my roommates and I ran a webcam [dhs.org] using this process. In this particular case, the video capture card lived in a Mac, but I could have done the same with my linux box and a shell script.
    _____________
  • BTW, the correct URL is not "www.gphoto.com", but [gphoto.org]

    -mdek.net [mdek.net]

  • Thanks, you're quite right that the proper URL is www.gphoto.org [gphoto.org], not www.gphoto.com. Unfortunately, your post had a malformed link so you you can't see it there either. Third time's a charm ... ;-)

    Thanks, RJS

  • I should really start using the preview button more often...


    -mdek.net [mdek.net]

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