digital camera for gel electrophoresis

Michael L. Sullivan mlsulliv at facstaff.wisc.edu
Thu Aug 15 14:06:35 EST 2002


>
>
>However, we got very poor photographs until we experimented with 
>filters for the camera lens. We found it necessary to use a UV 
>filter (Kodak Wratten No. 2B) plus a yellow/orange filter (Schneider 
>Kreuznach No. 67E or equivalent in other brands), otherwise the 
>background light drowned out the ethidium bromide-stained bands too 
>much. The filters we use are not attached to the camera lens, simply 
>taped over the hole in the box where we insert the camera lens to 
>photograph.
>
>We find this cheap alternative works quite well!
>
>Bev.
>

Interestingly, we've not had to use any types of filters to get good 
quality images with our Olympus (I was actually sort of surprised). 
Might it be that using the auto setting for exposure overexposes 
unless you are using a filter?  Frankly, I never even tried using 
auto setting-- I figured it wouldn't work well since a gel looks so 
unlike what most people take pictures of with digital cameras. 
Instead I just empirically tried some settings and adjustments in 
Photoshop.  What I ultimately found works for me is an exposure of 
1/30 sec, F2.8 (and this seems to work well for "dim" gels as well as 
bright ones).  Once I have the image in photoshop, I convert it to 
grayscale, optimize the brightness and contrast with "autolevels", 
and resize it to a reasonable dimension and dpi.  This has worked 
quite well for us, and as you point out is a rather inexpensive 
alternative to other imaging systems.

Mike
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