Bio-Rad Components for Older Model Spot Cutter - Manual (Page 17)

Note: Calibration creates several parameter and image files in the Install.prm directory in
the Discovery Series directory on your hard drive. These files should not be moved, deleted
or altered, or calibration will be affected.
When calibration is complete, you can proceed with normal use of the spot cutter. Once the
cutter is calibrated, you do not have to repeat the procedure during normal day-to-day use. You
may have to recalibrate if the instrument is moved or if the camera is moved.
Other Spot Cutter Controls
Click on the appropriate button to move the cutting tip to the front left corner of the spot cut-
ter or the back right corner.
You can simulate the action of the cutter and its camera by clicking on the Simulate Cutter and
Simulate Camera checkboxes. These checkboxes will cut off communication with the cutter
and camera if selected. In simulation mode, you will be prompted to open a file image of a gel
in place of the camera cutter image.
Section 3
Calibration
3.1 Camera Calibration: Lens Aperture Setting
The aperture setting on the lens is a black ring on the lens with a small black thumbscrew
attached. There are aperture settings marked on two sides of the lens. The white mark on the
ring indicates the aperture setting. F-stop setting 1.4 is maximum open for the lens; f-stop
11-16 is the maximum closed for the lens (16 is not marked but is past 11). See Figure 7 for
open and closed aperture settings. To adjust the aperture setting, loosen the thumbscrew,
move the ring to the desired setting and gently tighten the thumbscrew. Tightening the
thumbscrew is optional; the aperture setting does not drift but can be accidentally changed
if it is touched.
Fig. 7. Aperture at f-stop 1.4 for UV light mode. Fig. 7a. Aperture at f-stop 16 for white light mode.
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f-stop 1.4
f-stop 16