Bio-Rad Components for Older Model Spot Cutter - Manual (Page 18)

3.2 Camera Calibration: Focus
The lens on the camera should be locked in place once it is focused. To accomplish this,
the lens has a silver lock collar that is tightened after focusing is completed. Focus using the
following steps.
• Loosen the 2mm hex screw in the silver lock collar of the lens with the red handled
2 mm hex driver.
• Loosen the black aperture thumbscrew
• Set the aperture to the open setting of f-stop 1.4
• On the back portion of the spot cutter instrument, behind the cutting platform, is a black
toggle switch. This toggle switches the power to the white lights on or off. It is not the
mains power switch. Switch the toggle to the lights off position. Check that the lights are
off by pushing the red "Lights on" button on the lower front right side of the spot cutter.
If the platform lights come on, switch the toggle switch to the other position.
• Take the cutting mat, and any other materials, off the cutting platform.
• Click the "Focus Cutter Camera" icon from the Basic Excision Tool window.
• Click the "Auto-expose" button. The software will reset the exposure time of the images.
Click "OK" when "Auto-expose completed". Do not click “Stop”.
• Put the cutting mat and the Bio-Rad Focusing Target or the Calibration Template on the
cutting mat for focusing.
• You will see a zoomed in portion of the center of the platform in continuous acquire mode
in the window.
• Center the Bio-Rad Focusing Target so that you can see the fine lines that are close
together. Focusing the lens will resolve these lines from one another and sharply focus
on the lines.
• To focus, physically turn the lens and watch both the image in the window and the "Focus
levels" box. The image should resolve the lines and bring the image into sharp focus.
The "Focus levels" box is a gauge of the gray scale across the image. When the focus is
at the best focus, the "Focus levels" number should reach a bottom plateau. This is meant
as a guide rather than a definite number point.
• When the lens is focused, hold the lens in place with one hand and tighten the 2 mm hex
screw in the silver lock collar. This will hold the lens in the focus position.
• Click "Stop" on the "Focus cutter camera" window.
• If you are proceeding to Camera Alignment, you can keep the light setting at the same
"lights off" position for the camera alignment steps.
3.3 Camera Alignment—Rotation & Centering
(Tools needed: one 6 mm and one 3/16 inch mm hex driver to loosen screw in camera mount)
3.3.1 Rotation
• Place the Calibration Template on the cutting mat in the cutting platform. If the Focus
Cutter Camera window is already acquiring images, you do not need to close and reopen.
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