Macintosh Video Imaging,

comments by Matthew Cockerill cockeril@europa.lif.icnet.uk This information has a UK bias - any comments on the comparative situation in the US would be welcome. High quality still video imaging on the Mac is possible but there are many potential pitfalls. I haven't tried using the built-in capture facilities on the AV macs, but I wouldn't recommend it as I expect they are optimised for capturing motion video for quicktime. The input they take is S-video which is liable to be lower quality than a direct RGB input. There are quite a few of triple CCD cameras on the market which provide RGB outputs and a reasonable number of lines of resolution. We went for a JVC KY55E camera, together with a Falcon capture card Graphics Unlimited, a company based in Cambridge, England. The JVC camera is great, offering extremely high light sensitivity and the facility to do frame integration to go down to even lower light levels (not really necessary when lookig at embryos, but good if you want to use the same camera for fluorescence work. The Falcon capture card from Graphics unlimited is a mixed blessing. It is one of the cheapest 768x576 resolution, direct RGB-input capture cards on the market, but only works with dedicated software which is really designed for live video capture. There is a photoshop plugin, but it only offers a very small live video image to use for focussing. The dedicated software has a better live image, but for complete control, you need a separate monitor (connected up to the composite out on the JVC camera). The Kingfisher card, which preceded the Falcon, used to have an RGB port so you could monitor the same signal you were capturing, but the Falcon does not. Such is progress. Also, the card's software won't do timelapse (another feature lost from the Kingfisher), so your only option is to try and script Photoshop to take images at set intervals (not for the faint hearted). 24bit 768x576 RGB images produced by the card are 1.4MB when uncompressed, but obviously, these can be JPEGed to about 120Kb with almost no degradation of quality. It is very important to remember, though, that multiple cycles of JPEG compression cause *serious* degradation of quality, so it is always best to keep uncompressed copies of the files, and only compress at the latest possible stage. I recently spoke to JVC UK, and they have been working directly with someone at the MRC in Oxford on this sort of biological imaging. They have recommendations for a better capture card, with more flexible software, but it costs more than the Falcon. Total approximate cost of this system (including the Mac). Camera UK1500 (I don't know the html symbol for pounds!) Capture Board UK900 Powermac 6100 UK1000 So, pretty damn cheap, IMHO. Though, of course, it helps if you have access to color slide making and printing facilities... In the case of our Wild stereo microscope, we also had to spend about UK50 on a C-mount adaptor for the existing phototube (C-mount being a universal standard for CCD cameras). Matthew Cockerill cockeril@europa.lif.icnet.uk Cell Cycle Group Imperial Cancer Research Fund Clare Hall South Mimms Potters Bar Herts EN6 3LD