Dear Jürgen,
Unless you have to spend your money on a microscope immedeately, it is best
to evaluate demo instruments from different vendors on site at the same
time. All vendors will give you a demo instrument for a few hours to
several days.
The new Olympus LED instruments are excellent on paper, brighter than the
halogen lamps, and produce virtually no heat detectable by hand. However,
the new LED-containing base produces a diffuse light on the sample, compared
to the focused beam of the old halogen lamp bases. In my opinion, the
performance of the LED-containing base is the same or better of a halogen
lamp-containing base in the highly oblique and dark field modes. In the
bright field mode, the diffuse illumination of the LED base results in
"flattening" of the object.
Perhaps, our Olympus demo instrument (with a LED base) had flaws, but it
performed worse than an older generation Nikon instrument (halogen lamp)
with an objective of a smaller aperture.
Petr
-------------------------------------
Petr Leiman
École Polytechnique Fédérale de Lausanne (EPFL)
Cubotron/BSP-415
CH-1015 Lausanne
Switzerland
----- Original Message -----
From: "Jürgen Bosch" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, January 21, 2009 11:50 PM
Subject: [ccp4bb] temperature after 30 minutes using microscopes ?
Hi there,
*warning, reading beyond this line might expose you to non CCP4
related topics*
anybody out there who could do the following experiment:
Turn on your microscope and measure the temperature after 30 minutes
where you would place your precious crystal tray.
In particular I'm interested in LED versus Halogen driven models.
Is there anybody out there who would like to comment on LED driven
microscopes for our purposes ?
Thanks,
Jürgen
-
Jürgen Bosch
Johns Hopkins Bloomberg School of Public Health
Biochemistry and Molecular Biology, W8708
615 North Wolfe Street
Baltimore, MD 21205
Phone: +1-410-614-4742
Fax: +1-410-955-3655
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