Hi. I'm not an expert at gel image capture or analysis, but I can
think of reasons why a digital camera may not provide the results you
need. A reasonable quality scanner will collect more information
than a digital camera (I'm not sure of the upper limits in camera
technology (4 megapixel/$2000 maybe?). Taking the low road, where
pric/"performance" is comparable, a 2 MegaPixel camera will collect,
well, 2 Megapixels of information. a scanner at 300 dpi scanning a 5
inch by 5 inch gel will collect (300 X 5) X (300 X 5) = 2,250,000
pixels (units of information). pretty comparable, but most scanners
will scan at least 600 dpi and with the camera you will be contending
a lot more with ambient light issues, getting the gel you want to
digitize at the right length from the camera so you take full
advantage of each "pixel" on the camera ccd. I think this could
affect how well you can calibrate your analyses. For densiometric
analysis, I'm pretty sure you want a transmissive image (scanner with
transparency adapter) and not a reflective one (camera).
If anyone can refute my lay assumptions, please do! I'm pretty sure
there are commercial gel documentation systems using camreas and I
may be incorrect that more information is necessarily better. perhaps
I'm confusing documentation and quantitation.
here are some links that discuss scanning/camera in general and
scientific applications in particular:
http://www.scantips.com/
http://www.macfixit.com/ultimate/Forum9/HTML/000616.html
http://www.hs.washington.edu/locke/gel2.html
http://tuts.cit.nih.gov/gel_density_evans/gel_density_evans1/table.html
-James
>Hello All,
>
>I tried to use a Nikon Coolpix 800 digital camera in many ways to capture gel
>images (coomassie and silver stain) with very poor results. I bought an Epson
>Expression 1600 with transparency unit and am VERY pleased with its
>performance. I evaluated several commercial gel imaging units and found the
>Epson scanner to do as well or better at a much lower price. The scanner is
>also easy to use. The downside is that it is not set up for doing
>fluorescence
>but I am working on that. We store our data as color tiffs. Most 2D gel
>software requires greyscale images which we create by converting the color
>images using Photoshop or PaintshopPro. PDQuest software had problems working
>with our greyscale files. Phoretix software, which we purchased, works fine.
>
>Regards,
>
>Steve...
>
>"Bleibaum, Janice {Mass~Palo Alto}" wrote:
>
>> > Dear List,
>> >
>> > We would like to know if anyone has tried using a digital camera for
>> > capturing gel images. We have been using a flatbed scanner equipped to
>> > handle transparent images (transmissive light rather than merely
>> > reflective light) but not all the images captured with the scanner have
>> > been of the quality we would like. Specifically, we see spots in our gels
>> > that the scanner does not always record. If you are using a digital
>> > camera, we would like answers to the following questions:
>> >
>> > Which model?
>> > If you switched from a scanner, why did you switch? How much improvement
>> > in image quality do you see?
>> > What stain are you using? (We've been using colloidal Coomassie blue.)
>> > What format are using for the captured image? (We've been recording
>> > images as .tif files from the scanner.)
>> > Do you import the captured image into a gel analysis program such as
>> > Melanie or Imagemaster? Any problems with file formats?
>> >
>> > Any other comments which come to mind on this issue are welcome.
>> >
>> > Sincerely,
>> >
>> > Janice Bleibaum
>> >
>> > Janice Bleibaum
>> > Roche Bioscience
>> > Protein Sequencing and Proteomics
>> > 3401 Hillview Ave.
>> > M/S S3-1
>> > Palo Alto CA 94304
>> > (650)852-1639
>> > janice.bleibaum@roche.com
>> >
>
>--
>Steven H. Seeholzer, Ph.D.
>ICR Staff Scientist
>Fox Chase Cancer Center
>7701 Burholme Avenue
>Philadelphia PA 19111
>
>voice: (215) 728-1111
>fax: (215) 728-3574
>email: sh_seeholzer@fccc.edu
>
>trapper
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James VanEe Phone: (607) 254-4862
BioResource Center
Computing Facilty
170/171 Biotech Bldg Fax: (607) 254-4847
Cornell University
Ithaca, NY 14853 www: http://brcweb.bio.cornell.edu
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