Re: Cheap&cheerful setup for an occasional optical microscope photograph?

In article <cemgg1hdrjd84k1uubdq5977u8fugdim7n@xxxxxxx>, Charlie+ <charlie@xxxxxxx> writes 
On Sat, 20 Aug 2005 10:38:03 +0100, David Littlewood
<david@xxxxxxxxxxxxxxxxxx> wrote as underneath my scribble :

Hi David - dead right - all my trial pics were pink!  Thats only
because I hadnt tried hard eough, and actually the low temp lighting
gave better contrast!  Microscope also has Iris diaphrams,
apart from the condensers,  filter trays both in path and source etc.
and the camera also has (electronic) colour filters and fully settable
white balance as well as AWB - so full correction should be very
possible with all that lot and a bit of effort!
I could easily knock up an adaptor though this super compact camera
has no helpful threads like your Nikon and the lens is not in the
centre of the extending nose concertina -  would have to get the 4 jaw
chuck out!!  - Thanks for the post.
Charlie+

Don't be tempted to use the diaphragm to control the illumination, either; restricting this will seriously reduce resolution. The correct method is to close it until it just impinges on the field*. It is acceptable to close it a little further as this often gives more contrast at the expense of a little resolution.

*This is when the image just starts darkening. Otherwise, remove the eyepiece and look down the tube; then stop closing down when you can just see the diaphragm on the outside of the FoV.

Don't know your microscope. If it's a sophisticated one (with Kohler illumination) it will have two diaphragms, a field diaphragm next to the light, and an aperture diaphragm next to the condenser. The latter is the one described above, the former controls the amount of the FoV which is illuminated; if closed too much, it actually impinges as a sharp edge on the image as seen through the eyepiece, but does not change the brightness of the part inside (or the resolution).

I have seen adapters for cameras with no lens front thread; they fix to the camera base and hold the camera in the correct position. Can't give you details as I have never needed to research them.

David
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David Littlewood
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